Category Archives: Perennials

Advice, Climate Change, Compost, Drought, Native Plants, Perennials, Water

Searching for Rain – Rethinking the Future of our Gardens

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By Emma Murphy, Master Gardener

Heat. Humidity. Thunderstorms but no real rain. Dry soil.

cracked soil and dry leaves

What I wouldn’t give for a week of solid, consistent rain in our gardens. After the March ice storm, followed by a cool, wet spring and high water conditions until May, Mother Nature turned the water faucet off and we haven’t had solid rain for what feels like months.

I rarely have to water our established perennial gardens, which are a mix of native and non-native plants, but this month has been the exception.

So it’s time to think about the future. What can we do so our gardens survive (and thrive) during future dry or drought conditions?

Maintain Healthy Soils

Good soil is the foundation for good plant growth. Anything you can add to your soil like compost or other organic matter will make it easier for roots to penetrate deeper, creating more expansive root systems that can seek out water and nutrients. Check out Master Gardener Sharleen Pratt’s previous blog.

The result? Healthier, more drought-resistant plants. Good soils are better able to absorb surface water runoff, minimize erosion, and access nutrients and sediments.

hands holding soil with small plant seedling

Think About Future Plant Selection

Evaluate your plants for their resistance to dry conditions or drought; look for new plants (hey, who doesn’t want more plants?) that are identified as drought-tolerant or drought-resistant. Group plants according to how much water they need. Ask your local garden centre or nursery staff which plants they recommend.

Consider incorporating more native plants, which generally adapt better, have lower water demands, and fewer pest problems, plus of course the many benefits they provide to our pollinators and wildlife. In Our Nature has some great ideas.

bumble bee on native purple asters
Bumblebee on native asters

Use Mulch

Mulch reduces evaporation, moderates soil temperature, and inhibits weed growth. It is estimated that three quarters of the rain falling on bare soil is lost to plants through evaporation and runoff.

Use compost, wood chips, bark nuggets, shredded bark mulch, shredded leaves, or any other organic material to cover the surface of the soil at least 5 cm in thickness. More info and a deeper dive here.

shredded bark mulch
Shredded wood mulch

Water Well

Long, deep watering encourages roots to go deep down in the soil to where it is moist and a lot cooler. Water less frequently but for longer periods, so water reaches deep into soil. Good thorough watering promotes healthier plants.

Water only when necessary. Most plants will normally wilt in hot sun and then recover when watered. Also, a dry surface is not always a sign of water need. The surface generally dries out first and is not a true indicator of what is going on down deep near the plant root. Make use of a hand trowel or your fingers to check for moisture.

Weed Management

Weeds will compete with your plants for moisture and nutrients. Keep your gardens and areas beneath trees and shrubs weed free. Once the weeds are eradicated, apply mulch.

Consider Alternate Water Collection and Distribution Methods

Water harvesting is a great way to use water from your home’s roof and direct it onto the landscape, where the soil becomes your “holding tank.” The best example is using a rain barrel – we have various rain barrels and tanks in our garden and they are a great investment.

You can also practice ‘passive’ water harvesting by creating depressions that fill with water from the roof runoff or formal rain gardens, both of which help with stormwater runoff issues. Peterborough Greenup Rain Program

Investigate use of soaker hoses or other irrigation techniques using timers, which keep water on the soil and reduce losses by evaporation. Adjust watering frequency and amounts based on season, temperature, and amount of rainfall. Overhead watering uses more water and encourages fungal diseases.

rainwater barrel beside house
Rainwater barrel and water diverters – check out Rainbarrel.ca for location of sales

Practice Water Conservation Everywhere

Not just in your gardens. Water is our most valuable resource. Learn how to reduce water use throughout your house and gardens. The Simple Guide to Water Conservation and Make Every Raindrop Count.

water droplets on leaf
Drought, Garden rejuvenation, Perennials, Planting, Sedums

An Overlooked Group of Plants

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By Marilyn Homewood, Master Gardener

Now that the hot, humid days of summer are upon us, it is time to appreciate some of the unsung heroes of the garden such as the low growing sedums (aka stonecrops) and hens and chicks (Sempervivum). 

These are a large and diverse grouping of plants known for their thick, fleshy engorged parts that retain water making them incredibly drought resistant.  They are found on every continent but Antarctica and likely in all of our gardens.  Give them sunshine with good drainage and they will reward you for years to come.

Often, these plants are used as groundcovers playing second fiddle to our larger, showier specimens or artfully placed in rock gardens.  Why not consider bringing them out to centerstage? Their varied texture and colours can create a unique look. The drought resistant nature of the plants is on trend with our warming climate. 

sedum garden

Some years ago, I redid a south facing bed entirely in sedums and hens and chicks. The previous occupants were failing to meet the challenges of the climate. It has proven to be a bit of trial and error with some varieties working well, some being too aggressive necessitating their removal and some succumbing to winter kill.  The bed is still a work in progress.

Initially, I did lose plants to rot as the existing soil was rich and covered with cedar bark mulch.  After amending with a poorer quality of soil scavenged from the shoulder of my road as well as implementing the use of HPB (high performance bedding) as mulch, the plants took off. HPB is a type of washed, crushed, angular limestone chip that does not contain fines or dust, typically around 1/4 inch in size.  It is commonly used as a base material for patios, walkways, and other landscaping projects. It’s known for its excellent drainage properties and makes a lovely stone mulch.  As the plants grew, they expanded happily into the HPB.

rocks

Other applications for these plants include their use in containers.  I am fond of planting up an old boot for placement on the porch stairs.  The succulents do well and take little care.  At the end of the season, plants are tucked back into garden to overwinter.

More recently, specialized companies have been producing “sedum mats” for use on green roofs and on landscape applications.  Sedum mats are a mixture of hardy sedum species grown in 1.5 inch thick soil-less media on a biodegradable coconut fibre base.  These mats are cut and rolled up like sod and are laid out in a similar fashion to provide a continuous green covering.  They can tolerate light foot traffic and are often used in areas where conventional garden beds would prove difficult (rocky areas with little soil depth, accents around hardscaping, boulevards). 

Sedums and sempervivum are the ultimate in low maintenance, drought tolerant plants that are visually striking and unique. There are far too many varieties to list here but some that I have found attractive, hardy and would recommend growing are Sunsparkler Firecracker, Sunsparkler Lime Zinger, Angelina, Dragons Blood, Voodoo and John Creech.  Some nurseries specialize in these species and have a large selection to choose from. No need to worry about planting these in the heat or having to baby them along.  I have some empty spots to fill so I think I will be heading out to my favorite nursery near Bobcaygeon to acquire a few new varieties.

And thanks to Master Gardener MJ Pilgrim for the awesome photo of her hens and chicks in the vintage iron.

Bees & Pollinators, Insects, Native Plants, Perennials, Seeds

Myrmecochory – How Ants Help Expand Our Gardens

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by Emma Murphy, Master Gardener

Ants are everywhere, but only occasionally noticed. They run much of the terrestrial world as the premier soil turners, channelers of energy, dominatrices of the insect fauna ~ Bert Holldobler

This spring I noticed that my patches of native bloodroot (Sanguinaria canadensis) and large-flowered bellwort (Uvularia grandiflora) appear to have spread to places where I didn’t plant it. So that got me wondering “how did that happen?”

Large-flowered Bellwort (Uvularia grandiflora) with Wild Ginger (Asarum canadense)

Apparently the answer is myrmecochory, which is defined as the dispersal of seeds by ants. Many plants have evolved to depend on a specific group of insects to disperse their seeds—in this case ants!

Plants that use ants to disperse their seeds have a fat-filled structure on the seed exterior called an elaiosome, which is a super snack for an ant. These structures or “food bodies” are rich in lipids, amino acids or other nutrients.

Elaiosome (e-lay-o-zome)
(Greek: elaion=oil + soma=body) literally meaning ‘oil body’

Ant with Bloodroot seed (photo credit: Donna Bos)

Plants that use this technique include many of the spring ephemerals such as trout lily (Erythronium americanum), violets (Viola spp), trilliums (Trillium spp), bloodroot, wild ginger (Asarum canadense), dicentra (Dutchman’s breeches, squirrel corn, bleeding hearts), hepatica, spring beauty (Claytonia virginica), large-flowered bellwort, and sedges in the Carex genus.

How it Works

  • Elaiosome Production
    Myrmecochorous plants produce seeds with an elaiosome
  • Ant Attraction
    The elaiosome attracts ants, who are drawn to the food source.
  • Seed Transport
    Ants carry the seed back to their nest, where they consume the elaiosome.
    • Seed Dispersal
      The seed is then discarded, often near the ant nest, providing a good environment for germination and seedling establishment.

The seeds are dispersed away from the parent plant, which reduces competition with the parent plant and improves chances of successful germination in the new spot. The ants may also discard the seeds in nutrient-rich areas within the colony, further enhancing germination success.

Thanks to the ants, the seeds are buried in nourishing soil, protected from predators (e.g., slugs and mice) who would eat the entire seed, not just the elaiosome.

Myrmecochory occurs worldwide, with over 11,000 plant species depending on this partnership. In eastern North America, ants in the genus Aphaenogaster do the majority of the work. These ants nest in leaf litter and woody debris on the ground, so it’s important to minimize plowing and soil disturbance.  

Aphaenogaster worker ants can often be spotted carrying seeds back to their nest (Photo credit: Katja Schulz – Flickr)

Ants are Important

Ants are a vital part of our ecosystem and worth protecting. They are keystone species – their diversity and behaviour affect their habitats and the surrounding plant and animal communities. So by conserving ants, we protect many other organisms that rely on them for the lifecycles.

The intricate tunnels and galleries ants create loosen the soil and allow moisture, nutrients, and air to move downwards. They carry leaf litter, prey, and other food items deep into the soil, which then are broken down by other invertebrates and microbes into the nutrients that all plants need to grow.

So next time you see your favourite spring plant has popped up in another location, thank the ants!

Want More Information?

Don’t crush that ant—it could plant a wildflower

Ants As Seed Dispersers a.k.a. The Myrmecochory Episode!

Ants Aren’t Your Enemy

Advice, Bees & Pollinators, Garden Design, Perennials

Using Broken Branches as Plant Supports

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By Marjorie Vendrig, Master Gardener in Training

Gardeners and municipal services in Peterborough and areas hit by the ice-storm are busy picking up the broken branches and limbs and using them for city compost and recycling programs.

Another use for some of this wood might be found in our own gardens, repurposing them for use as stakes and supports. The timing for the ice storm was perfect; the broken branches are young and supple and without leaves so they can be bent easily and shaped to suit needs. Small branches can be bent or twisted to create low supports for perennials or annuals that become leggy as the season progresses or to prop up flowers as the plants bloom. Heavier and longer branches can be used as poles for teepees in vegetable gardens for beans and peas or for climbers such as sweet peas and clematis.

This Photo by Unknown Author is licensed under CC BY-SA-NC

British and European gardeners have historically avoided plastic and metal as garden supports, instead ‘pea sticks’ are the norm. Pea sticks are usually coppiced hazel branches, but any young pliable wood will work.  Birch, lilac, red dogwood, along with oak and maple twigs and branches are at the top of the list, willow is popular as well but it tends to root and sprout – an advantage or disadvantage depending on where and how it is used. In some cases, a branch with lots of twigs and small growth is the best choice as the plant will grow under and over the branches.  In in other instances the small twigs might appear messy and a visual distraction.  When selecting your sticks, it’s important to take into account your garden aesthetic – are you going for the scrambling abundance of a country garden, or the formal structure of a classic retreat? Sarah Raven, a well-known British gardener has taken things a step further and made an effort to use only native wood when creating plant supports for her vegetable gardens.

In the ice-storm clean up, I collected a few branches for use as supports. My sweet pea seedlings are ready to plant outside, they’ll be perfect growing up and around the broken branch of a very special cornus Kousa, a sad loss from the storm. The long stem on the bottom is cut off at a sharp angle to be pushed into the soft spring soil as deep as possible.  The spread of the small twigs and branches will be close to the ground within easy reach of the seedlings planted around the base where they will quickly grow up and through the twigs and branches. Clematis would also do well on this structure and it’s likely strong enough to withstand several seasons. The popular annual mandevilla vine is another good choice as a climber. All add vertical interest to garden design.

My scrambling cotoneaster became too leggy and suffered a lot this winter. It’s now had a hard prune and I am using the cut offs to create small branch cages around some perennials. Yarrow, nepeta, tradescantia, and phlox are good candidates for this simple approach. Four or more long branches, each about 3’ long and with a similar diameter were chosen.  The new spring growth from the cutoffs will soon turn brown so I snipped off the new

growth and twigs, then pushed the thick end of each branch into the soil about 6” from its base, repeating this at the other three corners, to create four points of a box around the plant. The upright ends of the branches are then bent into hoops towards the opposite corner and wound around one another to create a hoop. More support is provided at the front where the plant flops towards the sun. I’ve made the hoop about 2/3 the final height of the plant and should be able to increase the height a bit by untwisting the ends a bit, if necessary.  At the end of the season, I’ll leave the hoops in place if they are sturdy enough for another season or add them to the compost pile.

My technique is very much that of a beginner; I expect I’ll refine things with more practice. Even still, the natural wood hoops are more appealing than  a plastic pole with string around it. In formal gardens in the UK, I have seen cages of plant supports that are works of art in themselves. It all takes time and patience.

References

Sarah Raven, Using Native Wood Structures (Retrieved May 7, 2025)

Types of Woodland Management, (Retrieved May 7, 2025)

Longfield Gardens, DIY Plant Supports, (Retrieved May 9, 2025)

Gardens Illustrated, How to Make your Own Plant Supports and Protection That Are Easy, Cheap and Full of Charm, (Retrieved May 8, 2025)

Bees & Pollinators, Native Plants, Perennials, Websites

Invite These Super-Pollinators & Pest Managers to Your Garden

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By Silvia Strobl, Master Gardener

You may know that native bees are the most important of our native pollinators, but which insects are the second most important pollinators of food crops and native wildflowers?

Perhaps you’ve never heard of flower flies? Visiting flowers more often and moving more pollen than pollinators such as butterflies, flower flies range in size from less than 1/4 inch long to more than 3/4 inch long, but pollinate at least 72% of global food crops and about 70% of wildflowers (Pollinator Partnership, 2024).

Maybe you have mistaken their strongly contrasting black and yellow bands on the abdomen for a bee or a wasp? Their colouring mimics that of these stinging insects—an evolutionary development known as Batesian mimicry. The English naturalist, Henry Walter Bates, came up with this term for harmless species that take on the physical traits of dangerous or bad-tasting species. So although hover flies lack a stinger, their colouring imitates the warning colours of bees and wasps that do have stingers, thereby offering protection by deceiving predators.

The larvae of flower flies are stellar pest managers, consuming aphids, leafhoppers, mealy bugs and thrips. In fact, one larva can eat up to 400 aphids over its two to three week development!

Females lay hundreds of eggs, depositing each tiny white egg singly on leaves or shoots near colonies of aphids. The larvae hatch in two to three days and resemble small legless maggots,  ranging in colour from creamy-white to green or brown (Mahr 2025).

Four common flower flies that I have observed and photographed in my garden, and whose identity has been verified by experts on iNaturalist, are shown and described in the following. Lists of flowers visited are from Skevington et al 2019).

Caption: This Orange-legged Drone Fly (Eristalis flavipes) is found in a many habitats. It visits a wide range of flowers, including this Zinnia in my garden, but also Spreading Dogbane (Apocynum androsaemifolium), Button Bush (Cephalanthus occidentalis), Thistles (Cirsium spp.) Joe-Pye Weeds (Eupatorium spp), Apple (Malus spp.), Ninebark (Physocarpus opulifolius), Primroses (Primula spp.), Sedum (Sedum spp.), Goldenrods (Solidago spp.), Meadowsweet (Spirea spp.), Asters (Symphyotrichum spp.), and Viburnum (Viburnum spp.).
Caption: This adult Eastern Calligrapher‘s (Toxomerus geminatus) beautiful black and white pattern is well disguised on the disc flower of the native Lance-leaved Coreopsis (Coreopsis lanceolata). The adults consume both pollen and nectar, and have been recorded visiting: Joe Pye Weeds, Ninebark, Goldenrods, brambles (Rubus spp.), feverfew and tansy (Tanacetum spp.) and blueberries (Vaccinium spp.). The larvae pierce aphids and mites with their hooked mouthparts before feeding on them.
Caption: The Narrow-headed Marsh Fly (Helophilus fasciatus) is one of the earliest and latest flower flies, shown here pollinating late blooming Smooth Aster (Symphyotrichum laeve) in my garden. Some flowers visited include Button Bush, Joe-Pye Weeds, Grass leaved Goldenrod (Euthamia graminifolia), Ninebark and Golden Alexanders (Zizia spp.). The adults lay eggs on vegetation overhanging ponds and when the larvae hatch they fall into the water where they complete their development.
Caption: Transverse Banded Flower Fly (Eristalis transversa) on flower of the native Tall Coreopsis (Coreopsis tripteris).The adults consume pollen and nectar from:
Native shrubs such as Buttonbush, Ninebark, and Viburnums
Native coneflowers (Rudebekia spp.), Goldenrods, and Asters
Non-native winter cress or yellow rocket (Barbarea spp.), sedums, feverfew and tansy

There are 416 known flower fly species in eastern North America (Skevington et al. 2019). So I hope to observe and photograph at least a few more species on flowers in my garden this season! Nearly all flower flies can readily be identified by their:

  • Large heads with large forward-facing eyes that often fuse together. Bees have kidney-shaped eyes on the side of their heads.
  • Stubby, short antennae as opposed to the long antennae that bees have
  • Only 2 wings compared to 4 wings for bees and wasps (Erikson 2020)
  • A “false” vein in their wing venation i.e., a vein that is not joined to any others

From: https://ipm.ucanr.edu/PMG/S/I-DP-SYRP-KC.003.html#gsc.tab=0

How do you attract these super pollinators and pest managers to your garden?

  1. Flower flies prefer white and yellow flowers that are open and have easily accessible pollen and nectar, for example the disc flowers in the daisy (or Asteraceae family), but they also use orange, pink, purple, and blue daisy-like flowers. According to a recently published book about the flower flies of northeastern North America, native plants are essential to supporting a diversity of flower flies (Skevington et al. 2019). Non-native plants that attract flower flies include: Queen Anne’s lace, wild mustard, sweet alyssum, coriander, dill, broccoli, kale, lettuce, mustards, dandelion, plums and cherries (Mahr, 2025, Pollinator Partnership 2024).
  2. Don’t use pesticides since they can kill both the larvae and the adult flower flies.
  3. To give the larvae something to eat, tolerate some level of aphids and other pests in your garden.

Don’t be surprised if by doing these things you suddenly start seeing flower flies in your garden. Also known as hover flies, you may even observe their darting back and forth flying behaviour i.e., when males hover in the open hoping to attract a female, or when males of some species defend a territory.

Flower flies are some of the most beneficial insects you can have in the garden so invite them in by planting the annual non-native and native flowers they prefer.

Literature Cited

Erikson, B. 2020. Flower flies: insects with a “PR problem”. Wild Pollinator Partners.

Mahr, S. 2025. Hover, Flower or Syrphid Flies (Syrphidae). Wisconsin Horticulture, Division of Extension.

Pollinator Partnership. 2024. Flower flies—masters of disguise. 2-pages.

Skevington J.H., M.M. Locke, A.D. Young, K. Moran, W.J. Crins and S.A. Marshall. 2019. Flower Guide to the Flower Flies of Northeastern North America. Princeton University Press. 512 pp. (Note: all 6 authors are Canadians from Ontario).

Annuals, Light, Perennials, Planting, Seeds, Soil, Vegetable Gardening

March Madness

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by Cheryl Harrison, Master Gardener

March is the start of gardening season!  Let the seed starting begin.  My husband is the “seed starter” at our house.  I am the “seed buyer”, the occasional “assistant transplanter” and a very helpful critic.

Husband has the seed packets organized by type of plant (e.g. perennials, vegetables – tomatoes, Brussel sprouts etc., and annuals – zinnias, marigolds etc.) and by the date that the seeds need to be started. The dates are calculated by looking at the back of the seed packets to find the length of time from seed planting to when the plant may be moved outdoors (i,e. the last expected date for frost), which is early to mid-May in the Peterborough area.  For us, this means that the perennials are started first then the vegetables and the annuals.

Some supplies.

 In fact, the back of the seed packet will also tell you:

  • How deep to plant the seed and how far apart to space the seeds when planting in a tray or for direct sowing in the garden.  Planting in individual pots may be the way to go for some plants (e.g. tomatoes). 
  • The number of days from planting to when the seed sprouts (germination) and to when you may expect to harvest.
    • The growing conditions required for the plant.  This includes light, moisture and temperature.  Seeds are often started in a special seed starting mixture which is sterile.

Husband and I check the seeds every day to ensure that moisture levels are adequate.  The surface may be dry or barely moist but there should always be moisture below the surface.  There is a fan set up to circulate air back and forth over the seeded areas.  This helps prevent damping off.  Damping off is a serious disease of seedlings that are grown in cool and wet conditions. 

Repotting tomato seedlings.

A heated home is usually warm enough to start seeds – i.e. 21-27 degrees C (70-80 degrees F).  Seedlings need 14-16 hours of light a day.  Sadly, we do not have that many hours of sunlight in a day until near the end of April.  We use indoor grow lights which do work very well. Plants that do not have enough light will stretch and become weak and spindly as they stretch towards the available light.  This makes them more susceptible to disease and they may not do well when they are moved outside.

The seedlings are transplanted from their tiny starter pots, or tray, into larger pots after they have 2-6 new leaves.  These new leaves are in addition to the 2 small leaves (cotyledons) that are the first to emerge from the seed starter after germination.  The soil in the larger pots is potting soil not seed starter. 

Seedling with only cotyledons.

We are grateful to have a homemade greenhouse where the plants, in their larger pots, are moved to continue growing until they are ready to be planted in a garden.  Prior to the greenhouse, plants were kept inside under the indoor grow lights until the weather co-operated enough to plant them outside.

Tips

  • If you are new to starting seeds, I suggest starting small.  Seed starting, while fun, can be labour intensive with planting.  There is also the cost of startup supplies.
  • Remember to label your seeds with plant type and variety (e.g. tomato – Beefsteak).  Nothing is more frustrating than when you plant seeds but do not know if you planted a tomato or a Brussel sprout.
  • Ensure that you are not using old seeds.  Old seeds may not germinate.  Purchased seed packets will be printed with an expiry date. 
  • Moisten soil and seed starter before use.
  • Seed starting is great for children.  They get to plant seeds, then care for and watch their plants grow. 

For more information:

Information, Insects, Perennials, Vegetable Gardening

Why You Should Plant Flowers in Your Vegetable Garden

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By Silvia Strobl, Master Gardener

Flowers planted in a vegetable garden aren’t just beautiful, nor just an edible addition to your salads, and not even just a pollinator attractant for your zucchini crop. Did you know that specific flowers that attract beneficial insects by providing pollen and nectar resources, known as insectary plants, are one part of the botanical triad preventative pest management approach used by organic farmers that you can apply in your own garden? The other two parts of the triad are the desired crop (vegetable or fruit) and a trap crop that is more attractive to insect pests than the desired crop, hence luring pest populations away. The trap crop once infested with pests is sacrificed.

Field trials have demonstrated that planting both insectary plants and trap crops is more effective at reducing pest populations than using either method alone (i). Researchers are developing guidelines for the most effective triad plant combinations for a localities’ pest and beneficial insects. Additionally, they are testing optimal planting arrangements, for example, planting insectary plants along field edges and inter-planting trap crops with the desired crop.

In Quebec, researchers evaluated 10 different flowering plants for how well they attracted both (i) beneficial natural insects and (ii) typical insect pests. Weekly surveys found that beneficial ladybeetle (Coccinellidae family) captures were twice as high in Marigold (Targetes patula), Nasturium (Tropaeolum majus), Cosmos (Cosmos bipinnatus) and Common Yarrow (Achillea millefollium) as compared to the other six plants in the study. Meanwhile, captures of Tarnished Plant Bugs (Lygus lineolaris) pests were highest in Bee (or Lady) Phacelia (Phacelia tanacetifolia) while flea beetle pests (Chrysomelidae: Alticinae) were highest in Sweet Alyssum, White Charlock (Sinapis alba), and Marigold (ii).

Trap crops can be in the same family as the desired crop, but have to be more attractive to the pest. For example, in one study 10% percent of the Broccoli crop area was interplanted with the Brassica, Pac Choi to effectively lure away flea beetles (iii). Similarly, Blue Hubbard Squash, susceptible to Squash Vine Borer (Melittia cucurbitae), Squash Bug (Anasa tristis), and spotted and striped cucumber beetles (Diabrotica undecimpunctata, Acalymma vittatum), is used by commercial farmers as a trap crop when growing other squash, cucumbers and melons (iv).

Home gardeners can apply the botanical triad by interplanting trap crops and insectary plants in their vegetable gardens.

The Pac Choi trap crop is more attractive to flea beetles than Broccoli. Once flea beetles feed on Pac Choi they can easily be controlled by other means, for example, tilling the infected Pac Choi into the ground (Photo used with permission from Dr. Joyce E. Parker, The University of Sydney).


Trap Crops


Planting a diversity of trap crops is more effective than planting only one trap crop species. The trap crop should cover at least 10% of the desired crop’s planting area to be effective, and must be destroyed to kill the pest before it moves to the desired crop (iii). A few trap crops that have been found to reduce insect pests on common vegetable crops follow.

A few studies have found that basil and marigolds effectively reduced thrip and tomato hornworm populations in tomatoes (v). The author planted a few basil (in all 4 corners of the raised bed) and marigold plants into this tomato bed.

Insectary Plants


Flowering annuals like Marigold, Nasturtium, Cosmos, Bee Phacelia and Sweet Alyssum can be started indoors before transplanting the seedlings into vegetable gardens after the frost-free date. These will flower within a month and be able to feed beneficial insects, when pest populations peak and right into late fall. Planting a succession of native flowering plants near the vegetable garden can also provide habitat for beneficial insects as well as support pollinators.

These annuals can be purchased in garden centres, but are often only available as varieties with double flowers that either produce less nectar (because energy is put into petal production) or block pollinator access to nectar and pollen (vii). Choose single or heirloom varieties to maximize pollen and nectar for beneficial insects. It is also more economical to start your own plants, because you can be certain they haven’t been treated with synthetic pesticides. After all you want to attract beneficial insects that will in turn prey on or parasitize insect pests on your vegetables!

As you plan your 2025 vegetable garden, consider whether the botanical triad could help prevent or minimize any pest problems you may have experienced in the past.

Some flowers like Marigolds both attract beneficial insects and trap pests, here helping to protect the Armenian Cucumber in the author’s garden. The Sweet Alyssum in the bottom left corner (and elsewhere in the garden) has also been found to be both an insectary plant and a trap crop (ii).


References

i. Shesthra, B., D.L. Finke, and J.C. Piñero. 2019. The ‘Botanical Triad’: The Presence of Insectary Plants Enhances Natural Enemy Abundance on Trap Crop Plants in an Organic Cabbage Agro-Ecosystem. Insects: June10(6):181 https://www.mdpi.com/2075-4450/10/6/181

ii. Boisclair, J. E. LeFrancois, M. LeBlanc, M. Grenier, M. Lefebvre, & G. Richard. 2014. Beneficial and pest insects associated with ten flowering plant species grown in Québec, Canada https://orgprints.org/id/eprint/24006/1/24006-OWC2014-Boisclair-Canada-Flowering%20strips_MM.pdf

iii. Parker, J. & W. Snyder. 2014. Diversity by Design: Using Trap Crops to Control the Crucifer Flea Beetle. https://eorganic.info/sites/eorganic.info/files/u461/trap%20cropping%20flea%20beetle%20webinar_Final.pdf

iv. University of Missouri. 2017. Trap cropping: A simple, effective, and affordable Integrated Pest Management strategy to control squash bugs and squash vine borers. https://ipm.missouri.edu/MEG/2017/3/Trap_cropping/

v. Parker, J.E., W.E. Snyder, G. C. Hamilton and C. Rodriguez‐Saona. 2013. Companion Planting and Insect Pest Control. Chapter 1 in Weed and Pest Control – Conventional and New Challenges, Pages 1-30. http://dx.doi.org/10.5772/55044

vi. Hoidal, N. 2021. Companion planting in home gardens. University of Minnesota Extension. https://extension.umn.edu/planting-and-growing-guides/companion-planting-home-gardens

vii. Silva, E. 2021. Less showy flower petals mean more pollinators. Oregon State University Extension Service. https://extension.oregonstate.edu/gardening/pollinators/less-showy-flower-petals-mean-more-pollinators

Somewhat related:

HOW CHEMISTRY PLAYS A ROLE IN PLANT-INSECT RELATIONS IN OUR GARDENS

Grass, Light, Native Plants, Perennials, winter

Light in the Garden

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By Marjorie Vendrig, Master Gardener in Training

It’s the darkest time of the year, daylight is at its lowest, and most gardening has ended for the season. That doesn’t mean, however, that there is nothing in the garden to be enjoyed. Garden design and planting choices should take into account the many months when the garden is still and inactive. It’s during this time when, despite the lack of light and active growth, the garden is revealed. It is stripped bare of colour and the exuberance of growth is set aside. With the leaves gone and many small plants succumbing to frost, the garden reveals itself openly and honestly.  It’s odd, but in the dark days of winter there is more light in the garden. Unencumbered by layers of leaves, loud colours, or scrambling growth, the garden becomes airy and lets us see its bones and form. There is a lot to consider and enjoy when the garden, no matter how big or how small, is revealed.

The low slanting light of late autumn and winter is an important piece of the beauty of the garden. Glancing out my bedroom window first thing every morning, I’m drawn to the morning light shining behind the swollen, grey buds of the magnolia tree next to the driveway. The buds are soft and fluffy, vulnerable yet so full of promise. In a nearby garden, there are a few large clumps of Karl Foerster grass (Calamagrostis x acutiflora) that sway and drift with the slightest breeze. Their slender stalks are a soft gentle brown, somehow able to withstand strong winds and pelting rain. Fall blooming grasses are a particular treat in fall and early winter, the slanting light is illuminated through the fluffy plumes making a beautiful statement. Hameln (Pennisetum Alopecuroides ‘Hameln’) is a favourite but there are many to choose from including some special native ones such as Side -oats Grama (Bouteloua curtipendula)  and Prairie Dropseed (Sporobolus heterolepis).

Another subtle feature of winter light is the shadow effect. The gentle lengthened shadows created by tree structure, moving grasses, seed heads, or conifer form merit consideration when choosing plants and placement. They are certainly worth more than a glance on a spectacular bright winter day.

The dried flower heads of ever popular hydrangeas are a common winter garden treat especially when topped with a light dusting of early snow. Summersweet (Clethra alnifolia), a small summer flowering shrub, also retains dried flower heads through fall and winter. Other shrubs offer interest because of bark colour and texture (red twig dogwood, cornus sericea) or growth habit. Staghorn Sumac doesn’t take centre stage in the summer, but offers spectacular colour in fall.  In winter, its red fruits, antler-like branches, and graceful form make it a show-stopper.  Another shrub favourite in my fall and winter garden is Seven-Son Flower (Heptacodium miconiodes). It is an all-around wonderful, unique shrub with added appeal for its beautiful peeling bark in winter.  Other shrubs that hold particular appeal in the winter are Witch Hazel (Hamamelis virginiana)  and Corkscrew Willow (Salix babylonida).

Limelight hydrangea in the snow
Summersweet in the snow

Of course, conifers are the bones of any garden in winter. With different needle textures and lengths, and different shapes and forms, they provide obvious interest to every garden. When everything else is grey and brown, the rich textured green of a conifer stands out and when the snow comes along their interest increases. It’s important to have a variety of shapes and forms: cylindrical, mounding, conical, and weeping. In a small urban garden such as mine, I’ve found dwarf varieties and columnar species. One of my favourites is a weeping white pine (Pinus strobus ‘Pendula’), which is supported and pruned to fit a small spot.  It’s a lovely unique specimen tree with gentle movement, at certain times of the day its pleasure is doubled when the sun throws it shadow on the nearby shed. 

References

https://kawarthanow.com/2022/01/13/tips-from-peterborough-greenup-on-how-to-design-your-own-winter-garden/

Winter Gardens: Reinventing the Season by Cedric Pollet
This book features beautiful winter gardens across France and the UK

Bees & Pollinators, Birds, Native Plants, Perennials, Uncategorized

Native Grasses Provide Winter Interest and Feed the Birds

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By Silvia Strobl, Master Gardener

This week I’ve been enjoying watching a flock of American Tree Sparrows that have migrated south from their summer tundra breeding grounds to my garden north of Peterborough for the winter. While I have both sunflower and nyger feeders, they are feeding exclusively on the Big Bluestem and Savannah Grass seeds in my garden. Sadly, these native grasses seem to have a bad rap among gardeners which is too bad as they have many benefits for both you and local wildlife.

I have the following four commonly occurring warm season perennial native grasses in my full sun garden:

Big Bluestem (Andropogon gerardii) is a very tall (5 – 8 ft) grass with clumps that form a dense sod but does not creep by rhizomes. It competes aggressively with shallow-rooted flowers, so it is best planted with species that form deep tap roots or spring bloomers that go dormant in the summer. In my garden it is a fall season focal point at the back of a border behind Culver’s Root (Veronicastrum virginicum) which has a central taproot as well as underground rhizomes.

In early May, Big Bluestem still hasn’t emerged, but allium foliage and some blooming tulips fill the space (left). By late June, alliums appear to float above the Big Bluestem grass (highlighted in orange) that is now 2 ft. tall (middle) and hiding the bulb foliage. By late July, Big Bluestem grass provides a green backdrop for the white flower spikes of Culver’s Root (right).

Little Bluestem (Schizachyrium scoparium) is an excellent grass for gardens due to its shorter height (2 – 4 ft), clumping form, very showy silver-white seed heads, and bright red stems in fall.It prefers dry sandy soils.

Savannah Grass (Sorghastrum nutans)is another tall grass (5 -7 ft) for the back of the border. It tends to self-sow so the young seedlings require a little annual weeding.

Native grasses add movement and colour to the garden. Little Bluestem’s red stems are illuminated by early October morning sun (left) while the late afternoon August sun highlights the tiny golden flowers and flower stalks of Savannah Grass (right).

Sideoats Grama (Bouteloua curtipendula) is a hardy, short bunchgrass that spreads very slowly by means of short, stout rhizomes and doesn’t compete with other plants. Its deep fibrous roots make it useful on slopes to prevent erosion (or on the edges of slightly sloped garden beds as in my garden). Do not plant it in clay soils.

Sideoats Grama has delicate hanging flowers (left), and later seeds (right) that are held in spikes that fall gracefully to one side of the stem.

Benefits for you

As well as being stunning fall and winter focal points, the tall native grasses, Big Bluestem and Savannah Grass, make excellent privacy borders. Their very deep roots (5-6 feet or more) make them useful for erosion control on slopes. Each of these native grasses is drought tolerant. And, each creates excellent winter interest as they tend to maintain their upright form. Another bonus is that they all have low palatability to deer.

Big Bluestem (left) and Savannah Grass (right) stand tall in the author’s garden despite 12 inches of winter snow.

Benefits for wildlife

Many butterfly skipper and moth larvae feed on these native grasses and they provide critically important seeds and habitat for native birds in fall and winter.

An adult Delaware Skipper rests on a blade of Big Bluestem in the author’s garden (left). Big Bluestem is a host plant for this butterfly’s larvae. Both Little Bluestem and Sideoats Grama are host plants for Leonard’s Skipper caterpillars. The adult butterfly is seen here nectaring on marigold in the author’s garden (right)

American Tree Sparrows feeding on a buffet of Big Bluestem (left) and Savannah Grass (right) seeds in the author’s garden. It is fun to watch them “ride” the Savannah grass stems to the ground so they can more easily peck at the seeds some of which spill onto the fresh snow.

Native Grass Establishment and Maintenance

Most native plant nurseries stock these grasses and all of them are easily propagated from seed. Plant seedlings densely at 1 ft to 1.5 ft spacing to discourage weeds. Water during the first year while roots are getting established. Fertilization is not necessary. All can be easily divided, but Sideoats Grama should be teased apart, not cut with a spade.

Remnant pockets of native grasses like this one of Big Bluestem growing on the shoreline of Little Jack Lake (left) are good places to collect seeds to propagate your own plants (right). Never collect more than 10% of seeds.

Depending on how much seed the birds eat in winter, you might get a few volunteer seedlings. If you don’t want more plants, they are easily kept in check by weeding when they are small.

If weedy cool season grasses have seeded into native warm season clumps, use a propane torch in early spring to burn emerged leaf blades while warm season native grasses are still dormant. Be sure to first cut off last year’s dry stalks and have a hose nearby. Don’t do this on a windy day!

Big Bluestem, Savannah and Little Bluestem are 3 of the 4 dominant grasses found in remnant tall grass prairies and oak savannahs, of which less than 1% of their pre-European settlement extent remains in Ontario. (The other is Switchgrass (Panicum virgatum) which can self sow quite a bit so might not be suitable for small gardens.) These grasses are also found on dunes, sandy shorelines, rock barrens, roadsides, and hydro corridors. Including these grasses in your garden can help support some of the wildlife that rely on this endangered ecosystem.

REFERENCES & ADDITIONAL RESOURCES

Diboll, N and H. Cox. 2023. The Gardener’s Guide to Prairie Plants. Pages 302-303, 306-307, 326-329.

Ehrlich, P. R. D.S. Dobkin and D. Wehte. 1988. The Birder’s Handbook A Field Guide to the Natural History of North American Birds, The Essential Companion to your Identification Guide. Page 584.

Johnson, L. and S. Colla. 2022. A Garden for the Rusty-Patched Bumblebee—Creating Habitat for Native Pollinators. Pages 149, 150, and 159.

Map of Native Plant Nurseries in Ontario maintained by Halton & Area Master  Gardeners

North American Native Plant Society. 2017. Seed collecting and saving.

RELATED

GARDENING FOR BIRDS THROUGH THE SEASONS

A FEW OF MY FAVOURITE NATIVE PLANTS

EXPANDING YOUR NATIVE PLANT PALETTE

WINTER FAVOURITES

Advice, Invasive, Perennials

When Ground Cover Plants Take Over

1 Comment

By Carol Anderson, Master Gardener

When I recently purchased a new home, I was too preoccupied with the beautiful lake view to truly notice some of the gardening challenges that lay ahead for me. Once I began the process of itemizing what garden treasures I had, I became acutely aware of the gardening style of my predecessor … a style that included utilizing ground cover plants to “fill in” raised beds … and apparently the faster they spread, the better!!! The challenge I have ahead of me is the removal or containment of numerous ground covers that have invaded every inch of the property. In this segment I will briefly touch on the management and/or extraction of 4 different commonly used ground covers that range from just “annoying” to outright invasive.

Chameleon Plant,  Bugleweed, Yellow Archangel, Periwinkle

Bugleweed (Ajuga reptans):

Although not considered invasive, Bugleweed can become problematic if left on its own without management, as it has a tendency to spread into adjacent lawn areas. I personally like the dark burgundy-red foliage, however, on my property it has spread across an entire garden and into the lawn. Bugleweed spreads through “shallow” underground runners with new baby plants popping up at the end of the runners. As a result, it is not impossible to remove nor contain. In the spring, I will be digging up the new plants all around the edge of the garden border and installing edging below the garden surface to stop the spread into the lawn. Periodic thinning (by digging up and removing some of the parent plants in the clump) will help to keep it manageable as well.

Yellow Archangel or Golder Deadnettle (Lamium galeobdolon):

Although Lamium is a common ground cover used in many garden applications, it is invasive in Ontario. It has infested natural areas and will out-compete native groundcovers in the wild. Lamium  spreads by plant fragments, rooting along the surface on the stems (see photo below). However, it also can spread by seed which can then be carried into natural environments by birds.  For this reason, I will be completely removing it from several of the large shade gardens on the property and replacing with native species. Luckily it spreads along the surface and can be removed by mechanical means. This will be another spring project in the garden and once fully extracted, I will begin investigating other options such as anemone, wild ginger, bunchberry dogwood and ostrich fern for the heavily shaded areas of the garden.

Periwinkle (Vinca minor):

Periwinkle is a very common shade groundcover used by gardeners. It is considered to be invasive as it spreads quickly given the right climatic conditions. It poses a threat to natural biodiversity as it can out-compete other forest understory plants. However, because it spreads by rooting along the stems on the surface of the ground (stolons), it can be contained through proper management of the plant. I plan to dig up the roots and plants and cut back the excessive amount of Periwinkle in the garden, interspersing it with other shade loving plants. This will require ongoing observation and management on my part. 

Chameleon Plant (Houttuynia cordata):

Avoid, avoid, avoid. Although an attractive groundcover, chameleon plant will invade your garden and lawn very quickly and became completely unmanageable. It is a non-native that spreads by a highly dense deep underground network of roots (rhizomes)(see pics below). Even a small segment of root left behind will live and spread for years to come making eradication very difficult. This fall, I began digging around the perimeter of the patch well outside of where the plant is visible on the surface. I dug down 12 inches and was still running into dense mats of roots!!!  I then sifted through the soil to remove all plant segments and put the soil back. At this point I have just begun the process of eradication (Step 1) and will keep you posted on my progress in my blog next spring. If I need to resort to solarization (using the sun’s heat to kill the plants under plastic), then this might be the next step for me. Stay tuned!!!

If you are a fan of using plants as groundcover in your gardens and raised beds, proceed with caution. If it spreads quickly, filling in bare areas, then it is likely invasive at worst and hard to manage at best. Proceed with caution and be prepared to observe and manage the groundcover to avoid the situation where the plant literally takes over the garden, eliminating all other species. In addition, there are many native Ontario alternatives to the traditional groundcovers…try them out and enjoy (https://www.inournature.ca/native-groundcovers).