All posts by peterboroughmastergardeners

Outcompeting Invasive Plants, Part 1

By Laura Gardner, Master Gardener in Training

When it comes to dealing with invasive plants in our gardens, some can be quite challenging to control, let alone eradicate. In a system of Integrated Pest Management (IPM), gardeners may need to choose a number of different control methods and the methods considered need to make the least environmental impact. These methods involve cultural, mechanical, biological, and chemical options. In most invasive plant situations, choices will be cultural and mechanical. Chemicals may not be an option for home gardeners due to licensing, legislation, and product label requirements. However, some chemicals may be necessary in situations where there is a health and safety concern—e.g. Heracleum mantegazzianum (Giant Hogweed). Some of the usual methods that are used may include pulling, digging, cutting, removing flowerheads, sifting the soil for root fragments, smothering, or solarizing with tarps. Many invasive plants are difficult to remove in their entirety due to their extensive rhizomatous roots or their ability to produce many seeds that can last for years in the soil. Two unwanted plants that have popped-up in my garden in recent years are Campanula rapunculoides (Creeping Bellflower) and Allilaria petiolata (Garlic Mustard). My property is fenced but it is not closed off and so is open to seeds coming from other areas (including adjacent neighbouring properties). Because of this, my approach is about control of existing plants but also in preventing new ones from becoming established.

In addition to some of the methods mentioned above, two others you can add to your arsenal is to use mulch and to plant more densely.

Add Mulch

While the above-mentioned weed seeds do travel by wind, the majority of them will fall near the parent plant on the other side of the fence. All along the open fence lines I have added a thick layer of arborist wood chips. Adding a 4” layer will inhibit the germination of weed seeds as light is prevented from reaching them. Any seedlings that do germinate can be easily pulled as the roots cannot take a firm hold within the mulch. The mulch will break down over time and will need to be replenished.

Add Dense Plantings

e.g. Solidago Flexicaulis (Zig-Zag Goldenrod)

There is a wooded area near my house that is densely covered by a native plant called Solidago flexicaulis (Zig-Zag Goldenrod). Recently I noticed that there were only two or three Garlic Mustard plants amongst it. The Goldenrod was beating it! The Ontario Invasive Plant Council advises planting certain native plants at a density of 9 or 11 plants/m2 in order to compete with Garlic Mustard.[i] In addition to Zig-Zag Goldenrod these other plants are recommended as Garlic Mustard competitors:

  • Anemonastrum canadense (Canada Anemone)
  • Hydrophyllum virginianum (Virginia Waterleaf)
  • Hydrophyllum canadense (Canada Waterleaf)
  • Geum canadense (White Aven)
  • Matteucia struthiopteris (Ostrich Fern)
  • Viola sororia (Woolly Blue Violet)
  • Carex blanda (Woodland Sedge)
  • Mianthemum stellatum (Starry False-Solomon’s-Seal)
  • Athyrium filix-femina (Lady Fern)
  • Ribes americanum (American Currant)
  • Diervilla lonicera (Bush Honeysuckle)
Solidago flexicaulis (Zig Zag Goldenrod) and Parthenocissus vitacea (Woodbine), and Allilaria petiolata (Garlic Mustard) together in a wooded area in Peterborough

[i] Garlic Mustard (Allilaria petiolata): Best Management Practices in Ontario. Ontario Invasive Plant Council. p. 22. Online:

It’s Iris Time in the Garden!

By Chris Freeburn, Master Gardener

June brings a great show of Bearded Iris into the garden. Iris germanica flower in spring and although the bloom time seems short, the big colourful blooms are breath taking. Iris come in different heights, have big showy flowers in lots of fabulous colours and their elongated fan-like leaves give a different shape in the mixed border. There are 3 parts of the flower – “standards” which are the 3 upright petals, “falls” which are the lower petals usually hanging down and the “beard” which is the fuzzy hairs and is often yellow in colour. There are many varieties available, with colours ranging from shades of blue, purple, pink, peach, orange and combinations of colours where standards are one colour and falls another. Stunning!

Orange Harvest

Iris want a sunny location facing south or west, in well drained soil. They do not want to sit in water and will rot if they are too wet. Iris have rhizomes which produce roots to hold the plant in place and draw up water and nutrients. Rhizomes want their tops to be near the surface of the soil or slightly exposed, especially in heavy soil. A heavily mulched bed will not work for iris unless you leave a large area bare. Fertilize in early spring.

Raspberry Parfait

Dead-head flowers by cutting spent blossom stems right down, which encourages more bloom on rebloomers. Leaf fans should be cut back to 3” to 6” in the fall with sharp scissors.

Plants need to be divided every 3 to 4 years to reduce crowding and encourage blooming. Dividing should be done when plants are dormant in August or September. When dividing, check rhizomes for signs of disease and cut out any soft, wrinkled or marred parts. Let rhizomes dry overnight before replanting to allow cut areas to seal over to protect

Watch for Iris borer which will eat through the rhizomes. If you do get borers, dig up and cut off the damaged rhizomes.

Siberian Iris

Iris are often sold bare root from seed companies and there are several online iris companies in southern Ontario. They tend to ship for fall planting when plants are dormant. You can purchase plants in containers in garden centres in spring or summer.

Royal Botanical Gardens in Burlington have a wonderful display garden if you are up for a trip. Check out their website

Iris siberica is another showy plant in the early summer garden. Siberian Iris grow 15” to 36” tall with lots of smaller flowers having standards and falls. Their leaves are narrower and almost grass-like. Siberian Iris can be planted into the soil rather than on top although they still have rhizomes. They can take full sun or part sun and do like a moist area. Dividing needs only to be done every 10 years or if the centre dies out.

Siberian Iris: Such amazing detail!

One of the earliest iris is Iris reticulata which is actually a bulb that you would plant in the fall. They are short and usually purple.

In Ontario we have native iris that are classed as wildflowers and known as Flags. They include Iris versicolor which you will find in shades of blue and Iris lacustris which is a smaller wildflower and very rare. These are often used in pond settings as they prefer to be wet. Iris pseudacorus is the non native yellow flag iris which is listed  on the Ontario Invasive list.

Iris are poisonous for cats, dogs and humans if eaten.

For more information check out these websites:

Planting Trees

By Sharleen Pratt, Master Gardener

Image Courtesy of

Peter Wohlleben in his well-know book, The Hidden Life of Trees, describes how trees are like families, continually communicating and supporting one another. Trees improve soil and water conservation, moderate climate, increase the wildlife habitat, reduce stress and improve health.

It is imperative we continue to increase the tree canopy in our ever-growing cities.  This became more important after the recent storm that whipped through Southern Ontario and took out so many beautiful trees.

There are many factors to consider when planting a tree and it is easy to make mistakes.  I learned this the hard way this past month when I was able to literally pull a 9-year-old tree out of the ground.  Believe me, I am no incredible hulk!  I made many mistakes when planting that tree; the picture shows it was planted too deep, the roots girdled around the original root ball and by amending the dug hole with compost the tree likely resisted growing roots into the surrounding clay soil.

Image Courtesy of Author

Do your research and purchase a tree that is suitable for your yard conditions: 

  • How much sun and shade you receive each day?
  • What type of soil do you have?  
  • Would you prefer a large tree or one that is smaller and more suitable to an urban setting? 
  • What growing zone do you live in? (Check out this Zone Map if you are unsure)
  • Are you looking for a tree that will attract pollinators?   

I would suggest you consider planting a native tree. Trees that occur naturally in our surrounding area are better adapted to local climate and soil conditions and more resistant to disease. Oak trees are a powerhouse for feeding birds and attracting pollinators and insects, however, they are quite large.  A smaller tree to consider would be an Eastern Redbud or a Fall Witch Hazel.

Here is an article from Landscape Ontario with suggested native trees to consider.


In well-drained soils, the planting hole width should be two to three times the diameter of the root ball and only as deep as the root ball.  Widening the planting hole produces a hole with a greater volume of loose cultivated soil that allows rapid root growth.  This way roots gain access to a greater volume of loosened soil.  Do not plant the tree’s root flare below the ground.  The root flare should be within the top 5 cm of the soil surface.  Use a brush to find the top of the root flare which is where the structural roots begin.


Remove any grass roots, weeds, rocks or other debris from the planting hole. It used to be believed that you should fill the hole with an organic amendment such as compost, however, recent research has found that this doesn’t improve root development or tree growth and can sometimes be detrimental to tree performance and survival.  It is best to backfill in layers and lightly tamp and water to eliminate air pockets.  Additions of mulch and compost can be surface applied in future years to supplied much needed nutrients.


It is wise to build a 10 cm high berm of soil extending 15 to 20 cm around the periphery of the root ball.  It should be firmed and is intended to keep water from flowing away.


Apply mulch such as leaf litter or untreated wood chips evenly at the base of the tree.  It will help to reduce evaporation and suppress weeds.  Be sure to pull the mulch about 15 cm away from the base of the trunk.  The depth should be between 5 to 10 cm. I often see trees planted with mulch piled like a volcano.  This does not allow the water to penetrate to the roots and can also cause damage and disease to the trunk of the tree.


Only stake the tree if the roots will not support its height or if it is exposed to high winds. If a tree must be staked, place stakes no higher than 1/3 the height of the tree. Stake the tree loosely so it can move naturally in the wind. This movement will help to increase the tree’s stability.  The staking material should not constrict or rub against the bark of your plant. Remove stakes after roots have established, no longer than one growing season.


Remove all plant identification tags and any trunk protection or packaging material.

Supplemental watering is recommended the first 2-years after planting your tree. A sprinkle with the hose for a couple of minutes does more damage than good as this does not provide enough water to penetrate deep into the soil.  Newly planted trees must be watered regularly until frost.  Also, if water is pooling around the tree, cut back on the watering.

Do not be tempted to add additional fertilizer at this point.  Mineral imbalances can occur and cause more vegetative growth than root growth.

Do not prune the tree beyond removing any dead, diseased or damaged branches.

For further information, check out this Tree Planting Guide from Landscape Ontario.

In praise of the Trillium, our provincial flower

By Mary-Jane Pilgrim, Master Gardener

Most people know of the White Trillium (Trillium grandiflorum) as Ontario’s provincial flower. This is the flower featured on many of our provincial documents, from health cards to driver’s licenses. It was on March 25, 1937 that the Province of Ontario gave the trillium this honour.

Trilliums have three broad leaves, three small green sepals, three petals, and a three-sectioned seedpod. The “tri” in the Latin word trillium refers to these collections of three.

Trilliums are very slow-growing plants; their seeds take at least two years to fully germinate. The plant itself takes seven to 10 years to reach flowering size. After first flowering, it will bloom annually in early spring, with the blooms lasting for around three weeks. Trilliums can live for up to 25 years.

Did you know that the plants are phototropic? This means that the blooms will bend toward the sun and follow it across the sky.

You may not know that ants are involved in the dispersion efforts of the trillium. Ants are attracted to the protein-rich seed sac on the seeds which they eat after carrying the entire seed back to their nests. The actual seeds are not harmed during this process, and are later discarded to grow a new plant in a new location.

As a spring ephemeral, trilliums have a few short weeks in the spring to collect as much sunlight and nutrients as possible to be able to survive for the rest of the year. If trilliums are picked in the height of their flowering glory, they may not be able to collect enough resources to survive.

There’s a pervasive myth that it’s against the law in Ontario to pick or relocate these native plants. In 2009, former Peterborough-Kawartha MPP Jeff Leal introduced a private members’ bill called the Ontario Trillium Protection Act. Although the bill passed first reading, it never became law. If you do relocate these spring beauties or buy them from a garden centre, mulch with leaf litter for best results. Filtered light is best as they cannot tolerate much direct sun. The soil needs to be rich in organic matter, well-drained, and moist.

There are several varieties of trilliums in Ontario, with the most common being the White Trillium. The next common variety in our region is the Red Trillium which is also called “Stinking Benjamin” (Trillium erecta). Why? Go out this spring and find one and take a sniff. You may discover it smells a bit like rotting meat. Yikes! The aroma’s purpose is to attract pollinators, and in this case, the pollinators are green flesh-flies who are out in search of rotting meat on which to lay their eggs. Instead of finding the perfect nursery, however, they end up assisting the plant in its procreative efforts.

Plants are rarely boring, once you get to know them!

A Few of My Favourite Native Plants

by Emma Murphy, Master Gardener

I’ve been gardening for more than 25 years and, like many of you, thrill at the opportunity to discover new plants for my gardens. Over the past few years these have been mostly native plants, as I learn about all the benefits that they bring – here’s just a few examples of why native wildflowers, grasses, shrubs and trees do so much more than just add beauty to the landscape:

  • They support birds, pollinators and wildlife – native gardens attract birds and butterflies and provide habitat and food for native pollinators
  • They increase biodiversity – native plants increase garden health and resilience, and help contribute to a broader effect to nurture and sustain living landscapes
  • They’re tough and low maintenance – because they’re adapted to grow in their native range, locally native plants tend to thrive with little to no care and conserve one of our most precious resources – water
  • They help you save money AND create a healthier environment for people – native plants don’t require expensive fertilizers and chemicals, or toxic pesticides and herbicides
  • They help with climate change – no lawn mower costs or exhaust! and long lived native trees help store carbon dioxide
  • They make gardening easier – if you select the right native plants for your garden, you don’t have to modify or amend your soil

I’m just going to share three favourite native plants in my garden, with hopes that you may consider them for yours.

Culver’s Root (Veronicastrum Virginicum)

Culver’s Root offers a strong upright, architectural accent to any perennial garden that attracts attention from both people and pollinators!! It can reach heights of 5 feet if it’s happy (although mine hasn’t achieved that yet) and the spikes of white flowers open from the bottom up in mid-summer. It has finely toothed leaves that are lanceolate and occur in a whorl of 3 to 8 leaflets. The inflorescence has several wand-like flowering spikes that resemble an elegant candelabra.

Culver’s Root grows in zones 3-8, in full sun to part shade but it does like moist, well-drained soil. The seeds are so tiny that they should be directly sown on the soil surface in fall or in the spring – I’ve tried winter sowing some this year so we’ll see how that goes.

The plant really has no other synonyms; apparently the name was derived from a Dr. Coulvert, a late 17th to early 18th century pioneer physician who found laxative properties in the plant. More information here.

Cardinal Flower (Lobelia cardinalis)

Who doesn’t love bright red flowers in the garden? For those who say native plants can’t be showy I give you this amazing example to disprove that theory. Named for its scarlet red flowers, its tubular flowers are a magnet and important nectar source for hummingbirds and swallowtail butterflies.

Like Culver’s Root the flowering spikes open from the bottom to top and bloom for several weeks. They grow best in moist, rich soils in full sun to partial shade.

I’ve only had my plants for two seasons but I understand that the parent plants will not persist after a few years, so it’s important to either let it go to seed (so it reseeds naturally) or collect seed – this is another plant where I am trying out winter sowing (native plants are a great choice for this propagation method). While many sites will tell you it needs a really moist site mine have done fine, although I do keep the plants well watered in drier times. More information here.

Green Headed Coneflower (Rudbeckia laciniata)

Also commonly called Cut Leaved (or Cut Leaf) Coneflower, this is the straight species, not to be confused with the double cultivar many of us have in our rural gardens (often called the Outhouse Plant – or Rudbeckia laciniata “Golden Glow”).

Not a small plant (it grows 4 to 5 feet tall in my garden), it clumps and spread by rhizomes so only one to consider if you have the space! Its bright yellow, daisy-like drooping flowers with green centre disks (which can be about 3 inches across) bloom later in the summer season. It prefers moist soil, but grows well in average, medium, well-drained soil in full sun to part shade. In nature it is often found in woods, meadows, streambanks, and roadside ditches.

The Cherokee natives call this plant Sochan and the spring basal leaves are a traditional Cherokee food. Butterflies are attracted to nectar from the blooms and songbirds, especially American Goldfinches, eat the seed in the fall. It is moderately deer resistant. More information here.

So I hope you’ll take the opportunity to seek out native plants to add to your garden, finding ones that are native to your region and appropriate to your conditions. Happy Gardening!!


By Lois Scott, Master Gardener

It is early May and my husband has been watching the rhubarb emerging with great anticipation.  I like rhubarb, he loves rhubarb and it will soon be time to start harvesting the stalks (petioles)!

Rhubarb (Rheum rhabarbarum), native to central Asia,is an easy, hardy, and edible perennial.  Technically a vegetable but treated as a fruit, it is long-lived, easy to care for and bothered by few pests and diseases. 

Rhubarb is sold by ‘crowns’ or perhaps you can get a division of a plant from another gardener.  Spring and early fall are the best times to plant it.  Rhubarb likes a well-drained site with full sun (6-8 hours minimum).  Give your plant plenty of space to grow, about 3m2.  Rhubarb is a heavy feeder so mulch around your new or established plant with compost or well-rotted manure.  I generally give mine a spring dressing of compost as it starts to emerge in the spring.  Rhubarb should be watered deeply during times of drought.

A new rhubarb plant will need a couple of years to get established before you start harvesting it.  Don’t harvest any stalks the first year and then very little the second year.  The plant needs those large leaves to develop to provide energy for the roots and crown to grow.  Over the growing season, flower stalks will start appearing and these should be cut off at the base to reserve energy for the plant.

Rhubarb is ready to harvest when the stalks are 25 – 40 cm long.  Grab the stalk part way down and pull or twist to the side.  When I pull rhubarb, I come prepared with a paring knife and cut off the leaves after pulling the stalks and leave them as mulch.  Rhubarb leaves are toxic as they have high levels of oxalic acid, however they can be safely composted. 

Rhubarb is a cool weather plant so as the season warms up growth may slow down.  Let your plant rest so the crown can recover.  If you have an established plant that doesn’t seem to be as vigorous as it was, it may need division which should be done in early spring.  Dig up the whole plant if possible.  Rhubarb has a very deep tap root but if you capture enough, you can divide the plant making sure each division as at least one or two buds.  Plant your divisions with the buds 4 – 5cm deep, gently firming the soil.

The only other job to do is weed through all the tempting rhubarb recipes.  Enjoy!

Gardening Tools with Distinction

By Marilyn Homewood, Master Gardener

I appreciate a well made garden tool; the way it feels in your hand and the way it works.  Over the years, I have acquired many tools but not all are winners.  As time has passed and my needs have changed, some of my favorites have been displaced by newcomers.  With the coming season, I thought I would share some of my favourites.

The tool that is by my side constantly is my hori-hori knife, a one handed multipurpose tool, used for digging and cutting. It has a long steel blade that is smooth on one side and serrated on the other. The serrated edge is handy for cutting through roots and difficult weeds and the smooth side is more appropriate to delicate cutting tasks. The tool originates from Japan, where it has been used for centuries to remove vegetables and Sanasi plants from the mountains. The word ‘hori’ literally means ‘to dig’ in Japanese.

The point of the blade enables you to dig rows for seeds, seedlings, and holes for larger plants. There is a built-in ruler, which consists of notches on the blade. When not in use, the knife hangs in its scabbard on a hook in the mudroom where it is readily accessed before going outside.

Spring cleanup highlights the need for pruning shears or secateurs; a type of scissors for use on plants. I prefer bypass pruners as they make an accurate and clean cut.  I have used Felco pruners for many years and found them to be sturdy, they have replaceable parts (including the blade) and are available in many styles.  I use the Felco 12 and Felco 6 which are suitable for people with smaller hands. For woody plants that are too thick for pruners, I switch to loppers which are long handled two handed pruners. My flower shears are small needle-nosed pruners that can get into tight places while delivering a clean cut to the stem.

The spade that gets the most use is my rabbiting spade which was originally designed for digging out rabbit burrows. The blade is very long, curved and tapers towards the end. It is ideal when working in confined spaces or for transplanting plants and shrubs. It has a short handle and a classic YD handle.

For working on woody plants with a diameter larger than 2 inches, I turn to my Japanese pruning saw. Light weight with an ergonomic handle that helps to prevent wrist fatigue, its tooth size and geometry are chosen for cutting green and wet wood, ie, live wood. These saws cut on the pull stroke, which keeps the blade straight which I find makes it easier to use. It makes fast work of any task leaving a very clean cut.  The saws are available in a number of sizes and types.  I prefer to buy brands where the blade can be replaced when needed.  I use mine for everything from foraging for evergreens at Christmas to dealing with invasive trees and shrubs on the farm.

One of my first purchases was my Haws 9 litre watering can.  First designed in 1884 and virtually unchanged to this day, it is made from painted galvanized steel that is meant to last lifetime. It has an extra long spout and comes with a removable oval brass rose. The Haws is well balanced, making it easy to carry and tip.  When I do need to water plants, I do it by hand using the Haws and water at the base of the plant directly from the spout. It is quite accurate due to its balance.

From the oldest to the newest, meet my new broadfork, a tool that allows you to aerate your soil while preserving soil structure and microbial populations. Broadforks have two pole handles connected to a row of steel tines along a crossbar, which permits you to use your body weight to drive the tines into the ground while holding the grips. The tines loosen the soil to a significant depth.  Pulling the handles allows you to crack to soil slightly creating passages that allow air, water, and nutrients to reach deep into the ground and create a better growing environment. All this with no bending!!

“Tools of many kinds and well chosen, are one of the joys of a garden” ~ Liberty Hyde Bailey

Year of the Garden 2022

By Cheryl Harrison, Master Gardener

Canadians love to garden!  2022 is the Canadian ornamental sector’s centennial and has been declared by the Canadian Garden Council as the Year of the Garden.  For more information, check Year of the Garden.

Our gardens became even more important to us over the last couple of years while we were sheltering at home due to the covid pandemic.   2022 is a year for us to share our gardening passion and knowledge.  It is the mission of the Peterborough and Area Master Gardeners to inform, educate and inspire the residents of Peterborough and area to create healthy and vibrant gardens, landscapes and communities through the use of safe, effective, proven and sustainable horticultural practices.  Peterborough has even declared itself as a garden-friendly city as part of the Year of the Garden festivities!

So, think how you can “live the garden life” … maybe consider gardening indoors with house plants, or in containers on your balcony or create a new garden in your yard.  You could join your local Horticultural Society to learn more about plants and then perhaps become more involved in the community.  Your next step might be to become a Master Gardener!

The Peterborough and Area Master Gardeners will celebrate the Year of the Garden by partnering with the Peterborough Public Library to renovate the gardens around their Aylmer Street building.  The gardens had originally been planted with invasive plants.  We will remove the invasives and replace them with native plants from Grow Wild, Native Plant Nursery.  The Peterborough Kawartha Association of Realtors (PKAR) are providing some much needed sponsorship funding for the project.  We are planning to involve the younger crowd in some of the planting along with our great group of adult volunteers.  We hope that, with some growing time, the gardens will become a haven with native plants and local pollinators and a beautiful spot for human visitors to rest. 

June 18/2022 has been designated as the Year of the Garden day in Peterborough.  The opening of the newly planted gardens at the Peterborough Public Library will be on that date from 10 until 2 pm.  There will also be a story walk for children, a Master Gardener advice table and more.   Another great event happening that day is the Peterborough Horticultural Society’s garden tour.  Tickets will be on sale soon for the tour.  Follow the Peterborough Master Gardeners and the Peterborough Horticultural Association on social media for more information.

Winter Browning of Conifers

By Laura Gardner, Master Gardener in Training

This spring as I walk around my neighbourhood, I have noticed quite a few evergreen conifers with brown needles. The species that are commonly affected are mainly the dwarf and ornamental varieties such as Picea glauca ‘Conica’ (Dwarf Alberta Spruce), Thuja occidentalis ‘Smargd’ (Emerald Cedar), and Taxus spp. (Yew). Some of the more robust and resistant conifers are the parent species such as Thuja occidentalis (Eastern White Cedar).

Some Causes[i]

  1. Inadequate moisture
  2. Inadequate protection from sun and wind
  3. Rapid freezing/thawing
  4. Salt spray damage
  5. Root damage at transplant
  6. Late season pruning and fertilization
  7. Late fall transplant
  8. Genetic maladaptation

Cultural Practices for Recovery and Future Maintenance

Depending on the extent of the damage, these shrubs may recover and produce new growth. This process can be encouraged by additional watering and the addition of mulch. Shrubs should be well-hydrated up until freezing in the fall to prepare them for moisture loss in the following winter. Mulching helps protect shallow roots from drying out, can help limit frost-heaving, and moderates the temperature of the soil.

Prior to winter, consider adding some protection such as a burlap screen with stakes for plantings on the south and/or west side where it is sunny or windy or near driveways and walkways that are salted. Burlap can be wrapped around shrubs but should be kept loose so that moisture is not trapped. The advantage to a screen is that the area remains open to air and light. Salt, sun, and wind can draw out moisture from the needles and because the ground is frozen, the roots are unable to draw in replacement moisture. Planting these types of shrubs on the north and east sides, in less open areas, and away from driveways can minimize damage.

Shrubs that have been dug from the nursery field and then have been repotted for sale may be subject to some root damage/loss. This can be more problematic when transplanting late in the fall as there is limited time for root re-development. In addition, the ability of the roots to draw in moisture before freeze-up can be compromised. Refrain from pruning and fertilizing late in the summer as this can encourage a flush of late new growth—tender growth that is more susceptible to winter damage.

Conifers that are exhibiting winter browning:

Is Supportive Care Enough?

Perhaps—it is required in the first few years after transplant and probably they will continue to require extra support. However, some dwarf and ornamental conifer cultivars are simply not genetically adapted to thrive in this region. This is because they have originated from areas of more moderate climate and hardiness zones. When considering trees and shrubs, while some species are more adaptable than others, it is preferable that stock be grown locally and be from local cuttings and seed. Forest Gene Conservation Association notes that “bringing material in from dissimilar areas often results in low survival from heat stress or winterkill, frost damage, reduced growth rates, and increased insect and disease problems.”[ii] While climate change is indeed allowing us to push the envelope a little and plant some species from the next hardiness zone, and there are assisted migration[iii] programs for species, there can be a risk in transplanting certain plants from further afield. Plants are genetically adapted to follow a particular timed growth cycle. For example, a study of Quercus rubra (Red Oak) found that a specimen grown in Algonquin Park that was transplanted in the Niagara region stopped growing before the end of the growing season. It was genetically adapted to a growing season of 185 days but the growing season in Niagara is around 230 days. Another specimen grown in Niagara that was transplanted in Algonquin Park was genetically adapted to continue growing past the end of the growing season there and as a result suffered frost damage and browning. It would be weakened and be more prone to damage from disease and insects.[iv]

Another study of Picea glauca (White Spruce) in Alberta found that cold hardiness was determined to be the trait with the strongest genetic variation. Seed from plants originating from Ontario had high growth but a poor survival rate. Because they were accustomed to longer growth periods, there were more vulnerable to early damaging frosts. The plants with the highest survival and growth rates were grown from local stock.[v]

Before purchasing, determine your garden’s site conditions: soil, moisture, drainage, sunlight, wind, climate, and whether the trees or shrubs you are considering can adapt readily to the conditions. Climate change also needs to be considered as we experience increased drought and higher temperatures. Determine their origin. Ask the vendor where they were grown. If they originated from an area with very different conditions, consider giving them a pass. Realize that “if a tree is not genetically adapted to your site conditions, no amount of care will help it grow as vigorously as one from the appropriate source.”[vi]

Keep in mind the gardening adage, “the right plant for the right space.”

[i] Winter Burn. University of Wisconsin Garden Fact Sheets. Online:

[ii] Seed Source Matters. Forest Gene Conservation Association. Online:

[iii] Assisted Migration. Forest Gene Conservation Association. Online:

[iv] How Far Should the Seed Fall from the Tree? It’s a Question of Respecting Diversity: Genetic and Environmental. Online:

[v] Sebastian-Azcona, Jaime, et al. Adaptations of White Spruce to Climate: Strong Intraspecific Differences in Cold Hardiness Linked to Survival. Ecology and Evolution, vol. 8, no. 3, 2018. Online:

[vi] When Planting Trees. Forest Gene Conservation Association. Online:

Glorious Lilies

by Christine Freeburn, Master Gardener

One of the most spectacular blooming flowers in the garden are from the genus Lilium. The large 6-petalled trumpet flowers stand on upright herbaceous stems. The fragrance emitted from some can perfume the entire neighbourhood. Lilies form from bulbs that have scaly layers and depending on the variety can bloom in your garden for a short period from June or into the summer months.

There are hundreds of species and varieties, and more being hybridized each year. There are basically 9 different types described by the North American Lily Society. They include hybrids like Asiatic, Oriental, Longiflorum, Trumpet, Martagon, Candidum, American and Interdivisional as well as Species. Most are perennial in our zone, some are fragrant.

Lilies prefer full sun and need well drained soil to grow well. Lilies are toxic to cats. Many lilies from the Asiatic, Oriental, Trumpet and Martagon families are susceptible to attack from Asian Lily Beetle.

For more information about lilies you might want to add to your garden Ontario Regional Lily Society and North American Lily Society

Check out a previous article written by PMG Mary Jane Parker on Falling In Love With Lilies

Easter Lily

Easter Lily (Lilium longiflorum)

• Forced in greenhouses for bloom at Easter
• 2 to 3 feet tall with a slight fragrance
• Will take full sun or part shade in your garden
• If planted in your garden, should overwinter and bloom the next summer, but be patient as it has had stress put on it from being forced

Asiatic Lily

Asiatic Lilies (Lilium auratum)

• Look like small artichokes as they emerge in spring
• Long slender glossy leaves
• Varieties may grow from 1 to 6 feet tall
• Many colours available, no fragrance
• Easy to grow, bulbs multiply quickly, very popular

Oriental Lily – Stargazer

Oriental Lilies (Lilium orientalis)

• Pointy tips emerge from ground in spring
• Leaves are broader, slightly heart shaped and farther apart on stem
• Usually bloom in June with very fragrant flowers
• Slower to multiply than Asiatic
• Most popular of all lilies
• Popular varieties include “Stargazer” and “Casablanca”

Trumpet Lilies (Lilium aurelian)

• Tend to bloom earlier than Oriental and after Asiatic
• Fragrant multiple blooms on each stem
• Some varieties can grow up to 8′ tall
• Popular varieties include “African Queen”

Martagon Lilies (Lilium martagon)

• Known as Turk’s Cap
• Has blooms which tend to face downward
• Likes moist, well drained soil in sun to part shade

American Hybrid

• Native to North America and blooming mid to late summer
• Downward facing yellow flowers
• Sun to part shade and moist soil
L. canadense and L. michiganense are two varieties grown in Ontario

Interdivisional Hybrids

• Also know as “Orienpet”
• Cross between Oriental and Trumpet
• Lots of hybridized types available
• Easier to grow varieties

Madonna Lilies (Candidum)

• Similar to Easter lily, but susceptible to viral disease
• Bulb is planted near surface, not like other lily bulbs
• Difficult to find to purchase

There are many plants with “lily” in the common name that are not related to those mentioned above. Always look at the Latin name to determine what family plants belong to.

Daylilies (Hemerocallis) are a beautiful low maintenance perennial which grow in clumps.
Lily of the Valley (Convallaria majalis) is an invasive perennial! Do not plant, grow or share!
Toad Lily (Tricyrtis hirta) is perennial , 2′-3′ tall, likes partial to full shade and moist loamy soil.
Trout Lily (Eryyhronium americanum) is a yellow wildflower with mottled purple lance shaped leaves found in forests
Canna Lilies (Canna) are a tender perennial with rhizomes that need to be lifted in fall and stored over winter
And there are the houseplants Calla Lily (Zantedeshia) which likes moist soil and grows from rhizomes and the Peace Lily (Spathiphyllum) which is related to but not the same as calla lily.