Category Archives: Invasive

Advice, Invasive, Native Plants, Websites

The Fall of a Fall Favourite

October 24, 2022 peterboroughmastergardeners 4 Comments

By Lois Scott, Master Gardener

Sometimes it feels like my garden will never reach the ‘mature’ stage even though I have been gardening in the same spot for 36 years. There are a variety of reasons for that, but one major one was my need to remove plants that are now considered invasive. “Invasive species are considered one of Canada’s greatest threats to the survival of our wild animal and plant life. Invasive species kill, crowd out and devastate native species and their ecosystems”. https://www.invasivespeciescentre.ca/learn.

So, who were the super villains in my garden? I’m looking at you, Burning Bush (Euonymus alatus) and also you, Barberry (Berberis). I was initially truly disappointed when I realized they needed to go but then my short attention span came into play and I was on to the next thing. What new plants could I get to replace said villains?!!! And they are environmental villains:

Burning Bush
Japanese Barberry

Burning bushes are certainly very visible at this time of year due to their intense red foliage, but Chokeberry (Aronia melanocarpa) makes a wonderful substitute for both Burning Bushes and Barberry. They are native to Ontario, will grow up to 2.5 metres tall, have white flowers in spring and their fall colour is dramatic. They will grow in moist or dry areas and they attract pollinators and songbirds. There are actually many native shrubs that are very ‘ornamental’ and worthy garden additions. https://www.inournature.ca/best-native-shrubs

At the risk of blathering on about native plants, one small benefit for me is that if I choose a native plant that is not aggressive (rampant spreader etc) and is suited to the conditions of the site (right plant, right place) I won’t find myself having to hack out this year’s fan favourite that turns into next year’s invasive disaster. Always a good thing for me and the wildlife and pollinators in my garden!

Information, Invasive, Websites

Jumping Worms & Invasive Species Awareness

September 19, 2022 peterboroughmastergardeners Leave a comment

By Christine Freeburn, Master Gardener

Master Gardeners have been talking about the importance of controlling invasive species for years. Purple Loosestrife, Giant Hogweed, Buckthorn, Garlic Mustard and Dog-strangling Vine are on a long list of Invasive Plant Species.

You can check the list out at www.invasivespeciescentre.ca or www.invadingspecies .com

But there are more than just invasive plants. There are also invasive insects like Spongy Moths and Emerald Ash Borer. There are invasive fish and invertebrates like Zebra Mussels and Asian Carp. We have invasive pathogens like Dutch Elm disease (Dutch Ed: “Identified by the Dutch, not CAUSED by the Dutch”). And just recently, we have begun to hear about Wild Pigs and Jumping Worms.

I took part in a webinar presented by the Royal Botanical Gardens on Jumping Worms (JWs) earlier this month. Two speakers, Brook Schryer from the OFAH who works with the Invading Species Awareness Program and Dr. Michael McTavish with the Smith Forest Health, University of Toronto, spoke about the need to be aware of jumping worm sightings in Ontario. They gave information about Eddmaps.org where interested citizens can share their own findings. You can find a recording of this event at https://www.youtube.com/user/royalbotanicalgarden

Now is a good time to find JWs as they are adults at this time of year and can be better identified.

Jumping Worms are an invasive species of Asian worm that are slowly moving their way from the United States. They are voracious eaters and can consume much of the compost, topsoil and debris that lays on forest floors. They leave behind worms castings that are loose and crumbly similar in appearance to coffee grounds. They are often found in wet and shady spots and castings are spread evenly rather than in clumping piles. The castings can be a thin layer or can be 10 cm deep. It will appear as though the ground has been previously dug as the soil will be loose. Jumping worms are distinguished by their thrashing behaviour when moved or picked up. They have also been known to amputate their tails as a method of evasion from predators. There are usually many worms found together close to the soil surface. The worm body is smoother than our earthworm and tends to be more gray than red. The milking band or clitellum goes all the way around their body. Although the worm dies in the cold winter months, their cocoons survive, becoming juvenile worms in May and June and adults in July.

Left on their own, these worms can spread up to 10 meters per year. However, without human help, the spread could happen much quicker.

Research in Canada is happening, but we should all be aware of the dangers of this invasive species, and take precautions. We just need to think of the days before Phragmites showed up in every wetland and ditch in our area. Awareness and education are important.

Check out the EDDmaps.org site where you can see where actually sightings of invasives have been recorded. The two presenters encouraged us to go out and search for signs of the Jumping Worm and report it to the EDDmaps, whether a positive sighting or a negative one. You can also call the Invading Species Hotline at 1-800-563-7711 if you have a concern.

Advice, Invasive, Native Plants, Websites

Outcompeting Invasive Plants, Part II

August 8, 2022 peterboroughmastergardeners Leave a comment

By Laura Gardner, Master Gardener in Training

This article was published in err a couple of weeks ago, and is being republished today as a corrective measure. Apologies. -Ed.

Back in a June post[i], I referenced the Ontario Native Plant Council’s best management practices for Alliaria petiolata (Garlic Mustard).[ii] In it they referred to certain native plants that can be used to outcompete it. I would like to mention one other that I am fond of having in my garden. Packera aurea (Golden Groundsel) has a diminutive orange inflorescence and is native to the Peterborough area. It can be aggressive as it reproduces through rhizomes and adventitious shoots on the stems. It is better situated in moist soils and so it may be more subdued in a drier location. In her blog, The Humane Gardener[iii], Nancy Lawson discovered that when she inserted clumps of Golden Groundsel into patches of Garlic Mustard, the latter quickly became surrounded. Garlic Mustard is known to be allelopathic and inhibits the growth of some plants. However, Golden Groundsel does not appear to be inhibited by it.

Anemonastrum canadense (Canada Anemone) is a beautiful vigorous native ground cover that performs well in sun to shaded environments; although it can develop brown leaves in more arid conditions. I am using it to limit the advance of Campanula rapunculoides (Creeping Bellflower). The intent is to envelope it so that it is unable to photosynthesize, grow more foliage, and store energy in its roots. One might argue that this is simply a matter of replacing one problem with another. While it is true that Canada Anemone can be overwhelming, it may be limited by deadheading the flowers, removing rhizomes, adding mulches, and by installing edging below the soil surface. As a native plant, it supports pollinators such as miner bees, sweat bees, and hover flies. The Xerces Society notes that it supports “conservation biological control.”[iv] This is a plant that attracts beneficial insects to your garden which in turn will help control other insects that damage your other plants.

So far, the Creeping Bellflower’s development has been slowed but there are still some basal leaves within the patch and at the perimeter. Right now, it is still a team effort: Canada Anemone and me.

[i] Outcompeting Invasive Plants: Part I. https://peterboroughmastergardeners.com/2022/06/13/outcompeting-invasive-plants-part-1/

[ii] Garlic Mustard (Alliaria petiolata): Best Management Practices in Ontario. Ontario Invasive Plant Council. https://www.ontarioinvasiveplants.ca/wp-content/uploads/2016/07/OIPC_BMP_GarlicMustard.pdf

[iii] How to Fight Plants with Plants. The Human Gardener. Online: https://www.humanegardener.com/how-to-fight-plants-with-plants/

[iv] Habitat Planning for Beneficial Insects: Guidelines for Conservation Biological Control. Xerces Society. http://www.xerces.org/publications/guidelines/habitat-planning-for-beneficial-insects

Advice, Invasive, Native Plants, Websites

Am I a Problem?

February 28, 2022 peterboroughmastergardeners Leave a comment

By Cheryl Harrison, Master Gardener

Well, yes … I am, but I have a plan. February 28-March 4/22 is National Invasive Species Awareness Week. This is an international event whose purpose is to raise the awareness of invasive species. “Invasive terrestrial plants in a forest ecosystem can be trees, shrubs, or herbaceous plants that have been moved from their native habitat to an introduced area where they are able to reproduce quickly and crowd out native species. These plants are introduced and spread by infested packaging material, seed dispersal by both environmental and human sources, or by escaping from gardens.” Also look at Ontario’s Invading Species Awareness Program for more information.

Biodiversity is essential to the continued healthy life of an ecosystem. Invasive plants can quickly destroy it and humans require the natural resources found in a healthy ecosystem. We need food and we need water to survive. We are a part of the ecosystem too. Doug Tallamy says it best in his book, “Bringing Nature Home” where he writes “…ecosystems with more species function with more efficiency, are better able to withstand disturbances, are more productive, and can repel alien invasions better than ecosystems with fewer species.”

I became aware of invasive species about 15 years ago when on my walk to work, I noticed some English ivy (Hedera helix) growing in a small wooded area. Then, I realized that English ivy had totally carpeted that area. There were no other plants! A couple of years later, I saw the same thing but this time, it was a larger forested area and the culprit was goutweed (Aegopodium podagraria). Since then I have read more about invasive plants and, sadly, now often see problem areas.

So, back to my plan. I was aware of some of the invasive herbaceous perennials so had steered away from them. See terrestrial plants and aquatic plants for more information. However, my husband and I are tree lovers and have a rural property so we frequently indulge in purchasing new trees to add to our collection. Unfortunately, we ended up with two Norway maple (Acer platanoides) trees, two burning bush (Euonymus alatus) and a barberry (Berberis thunbergii) shrub. This year, I plan to convince my husband that they must go. I would like to replace the trees with two red maple (Acer rubrum) or perhaps a couple of sugar maple ((Acer saccharum). The burning bush will be replaced by a couple of native viburnum maybe nannyberry (Viburnum lentago) and the barberry, well, it will be replaced by a native bush honeysuckle (Diervilla lonicera). See Southern Ontario Grow me Instead Beautiful Non-invasive Plants for Your Garden. This is a great resource. It includes some native and some non-native plants to include in your garden plans.

I am inspired to be a better gardener every time I write a blog for the Peterborough & Area Master Gardeners. I hope that you will have a look at some of the links above and below and be inspired too. Please only use non-invasives in your gardening plans this year.

I also recommend reading, or re-reading, a blog by Laura Gardner, Master Gardener in Training posted on February 2/2022: Expanding Your Native Garden Palette. For more information on what to do if you have a problem, see Best Management Practices Data Base .

A new group on Facebook is the Canadian Coalition for Invasive Plant Regulations. The group is very concerned about the spread of invasive plants in Canada and would like to do something about it.

Advice, Bees & Pollinators, Garden Cleanup, Garden rejuvenation, Invasive, Native Plants, Perennials, Planting, Weed Control

Ditch Lilies – a Cautionary Tale

August 16, 2021 peterboroughmastergardeners 4 Comments

By Emma Murphy, Master Gardener

Once upon a time there was a gardener who wanted something that grew quickly to screen a neighbour’s unsightly yard and house addition. She noticed that the ‘ditch lilies’ that surrounded her front yard tree (already there when she moved in) seemed to be pretty vigorous, so she planted a row of them between the yards, along with some small bridal wreath spirea (Spirae aprunifolia).

What she didn’t realize was that she had unleashed a horrible monster into her garden, one that quickly engulfed any other plants, sucked all the moisture out of the soil, and eventually killed most of those spirea.

Yes that gardener was me, many years ago, before I knew better and before I became a master gardener. So this year I knew I had to finally tackle the monster, remove all these plants, and reclaim this garden area. I knew how much work it would be (it took me three weekends this spring), but I got it done. Here’s my story…

Even though you see it growing in ditches around the province, Hemerocallis fulva (aka ditch lily, tawny daylily, orange daylily, tiger lily) is native to China, Japan and Korea and was introduced to North America in the early 19th century. They spread via seed and a network of tuberous roots, and can reproduce and proliferate from a small fragment left behind during removal. In 2020 the Ontario Invasive Plant Council added this plant to their invasives list, and their Grow Me Instead Guides offer some native alternatives to consider.

Screen capture from the Grow Me Instead Guide on Hemerocallis fulva

So this was my garden bed in May this year – just waiting to burst out and take over, again. Every single one of these plants had to be dug and lifted, making critically sure to get every last bulb. These photos show how many bulblets can be on just one stem – it was quite overwhelming to think of the job ahead.

All the plants that were dug out were put in black plastic garbage bags and left out in the hot sun beside our barn for a month. At last count I used 45 garbage bags, and they were a slog to carry as they were heavy!! Eventually they went to our rural dump, where the hot composting they do should ensure their demise.

Bit by bit, over three weekends, I got them all out. It was beneficial to have a dry spring, as it made digging them out a little easier. But still a workout!

Chipping away at the ditch lilies. Not for the faint of heart

Once everything was cleared out, I weeded the soil for anything else. All that remained were my tulips and a few hardy perennials that had been gasping for air for more than a decade.

With a fresh load of soil on top and a final check for bulblets done (and knowing that I would have missed a few), I put in some new plants, aiming for 50 percent native plants (those marked with a *). The area has both sun and shade spots so I needed to be careful with my choices.

For sun, Echinacea*, Gray-headed coneflower* (Ratibida pinnata), summer phlox (Phlox paniculata), American Witch Hazel* (Hamamelis virginiana), New England asters (Symphyotrichum novae-angliae), Sedums, Switch grass* (Panicum virgatum), Lesser catmint (Calamintha nepeta ssp. nepeta), Black-eyed Susans* (Rudbeckia hirta), lupins, Giant fleeceflower (Persicaria polymorpha), Cyclindrical Blazing Star* (Liatris cylindracea)[once I can convince the bunnies to stop eating it – see green covers], and Virginia Mountain Mint (Pycnanthemum virginianum).

For part shade/shade, Mourning Widow Geranium (Geranium phaeum), Purple Flowering Raspberry* (Rubus odoratus), hostas, Sensitive Fern* (Onoclea sensibilis), Virginia Waterleaf* (Hydrophyllum virginianum), Columbine (Aquilegia), Starry False Solomon’s Seal* (Maianthemum stellatum), Buttonbush* (Cephalanthus occidentalis), Zig-zag goldenrod* (Solidago flexicaulis) and Berry Bladder fern* (Cystopteris bulbifera). Also the infamous Outhouse Plant (Rudbeckia laciniata ‘Hortensia’), to be replaced with something else next year. Any suggestions for fast growing native shrubs that can handle part share welcome!

The garden bed needs time to fill in, so we’ll see what it looks like next year. In August I went back into the bed and sure enough, there were new ditch lilies growing in a few places. Remember it only takes one bulblet for them to grow. But half an hour later they were all gone as well.

I suspect I will on alert for the odd ditch lily plant showing up for the next few years, but I’m really proud to have removed this nasty invasive plant from my garden and rejuvenated it with native plants. And my two lovely sugar maple trees are glad for some more breathing room.

NOTE: The orange, single flower Hemerocallis fulva is the only daylily currently listed as invasive. It is a diploid daylily. Most cultivated daylilies are triploid and do not spread invasively like the ditch lily.

Advice, Compost, Drought, Information, Invasive, Perennials, Propagation, Vegetable Gardening

Year in review: part 1

November 16, 2020 peterboroughmastergardeners Leave a comment

By Suzanne Seryck, Master Gardener

It is a beautiful fall day as I’m writing this blog, blue sky and temperature around 20 degrees. I have just finished the last jobs before putting my garden to bed for the winter. The last of my 30 or so bags of leaves have been mulched and put onto the gardens, apple trees have all been wrapped to prevent rabbits and squirrels from eating the bark off of them, and I have emptied the rain barrels onto the trees, shrubs and fruit bushes.

Time for both a well earned rest and for me to put together my garden review list for this year. All season long I jot down notes of anything that is working, not working or something that I need to concentrate on or remember for next year and then I compile it into one list. This year I’m going to share my list in this blog, although the list is a little long for just 1 blog so I’ll split it in 2 parts.

I don’t plant many annuals in my garden–a couple of urns out front with 2 hanging baskets, and some large pots at the back. I love the colour that annuals provide all season, but they typically need more watering than I like to do, and I find them expensive. Last year I overwintered some cuttings I took from both my coleus and sweet potato vines as well as overwintering the purple fountain grass. All the cuttings worked great, and in the spring after hardening off I was able to plant them into my pots and urns; they grew really lush and full. The green potato vine was much stronger and more robust all season than either the purple or copper plants, however the purple fountain grass grew back very slowly never really getting the vibrant purple colour back. This year I’ve taken even more cuttings from my coleus along with the green and purple sweet potato vine. However, I decided that I would rather spend the money on new fountain plants each spring.

I have 2 large compost piles that I use all year, filling to the top with leaves and then burying food scraps the rest of the year. This year I religiously turned the one pile every couple of weeks starting as early as I could and was rewarded with compost all gardening season. In the second pile though, a couple of errant zucchini plants started growing producing lush growth and lots of flowers and I thought ‘why not leave them?’. I’m sure you can guess the rest, not a single zucchini and I was not able to use any of the compost all season. Note to myself if anything accidentally grows out of the compost next year, turn it back in.

For the first time this season I grew Sicilian zucchini, now I didn’t actually realize I had bought this variety until it started growing up the espaliered tree fence and growing 2-3 foot long zucchinis. I’m definitely going to grow them again next year, although in a different location. When the frost finally killed off the plants and we pulled them off the fence, the wires were no longer taut and needed some tightening. Another point to note is that the zucchinis were consistently eaten throughout August and September when they were barely an inch or two longer. I’m not sure why that only happened later in the summer, maybe the squirrel or rabbit population doubled when I wasn’t looking. I’m thinking of placing bags over the fruit as it is growing, hoping by the time it gets to a foot or more it won’t be quite so attractive to predators.

I tend to leave my perennials to self seed as I love growing plants from seed; it is probably one of my favourite things to do in the garden. I have set aside a nursery plot and any seedlings I find in the garden I move into the nursery. Unfortunately this year I noticed a definite increase in the number of swamp milkweed, verbascum and New England asters seedlings. Now I love these plants, but they are taking over both my garden and my garden paths. I grow Verbascum nigrum which is a beautiful stately plant with either yellow or white flowers. It tends to be a short lived perennial but as it grows profusely from seed, I always have a few plants in my garden. Swamp milkweed is a host for the monarch butterfly; in my garden I have both pink and white flowering plants. They prefer moist to wet soil and because my soil is dry, they are also short-lived. Not so the New England aster; this is a native aster which grows 4 to 5 foot with beautiful purple blue flowers, however it can get very large in just a couple of years. Next year I have to dead head these plants, leaving only a couple to go to seed, which I can then harvest and plant in a specific area of the nursery.

Verbascum in author’s garden; this one plant bloomed all summer.

On the positive side, I was surprised by an abundance of aquilegia (commonly known as columbine) in my front garden that I was not expecting. I had left the seedlings thinking from a distance they were meadow rue, only to be surprised by this showing:

Aquilegia are one of my favourite plants, but I tend not to grow them as I find in my garden they are eaten by slugs. One day I have a beautiful plant in full flower, and the next day just a few stems still standing. I’ve slowly been replacing them by meadow rue, which for me has a similar lacy look, which I like when paired with hostas and brunnera. Slugs don’t seem to like meadow rue, but for some unknown reason this year, they also left the aquilegia alone. Based on this I have since ordered some seeds from the native aquilegia, Aquilegia Canadensis, which has beautiful red and yellow flowers and also likes sun to part-shade.

And finally the dreaded creeping charlie in my lawn. I have a small lawn which I have been overseeding with clover in my attempt to make the lawn healthier and more low maintenance. Clover has a lot of great benefits in a law including growing in poor soils. Clover is a nitrogen fixing legume, so it will improve the health of the soil and the surrounding grass, needs less watering and mowing, attracts beneficial insects, and crowds out weeds. Unfortunately though it does not crowd out the creeping charlie and actually seems to co-exist with it harmoniously. The recommended solution in a lawn is to hand pull the creeping charlie and because it grows by rhizomes which then root into the soil, removing all parts of the plant can be very time consuming. I have heard that it is easier if you soak the ground first or weed after it has rained. Note to myself, recruit an army to help me after each rainfall in the spring, either that or learn to love it!

Advice, Invasive, Websites, Weed Control

Invasive Species

May 4, 2020 peterboroughmastergardeners Leave a comment

By Sharleen Pratt, Master Gardener

According to the Ontario Invasive Plant Council, an Invasive Species is an alien species whose introduction or spread negatively impact native biodiversity, the economy and/or society, including human health.

Therefore, an invasive plant species is often a plant that has been brought into Ontario from another country, possibly for medicinal reasons or as an addition to one’s garden. For various reasons, it becomes aggressive, spreads quickly and often displaces native plants.

Here is a detailed description of five invasive species that could show up in your garden. They are all Category 1 Invasive as designated by the Credit Valley Conservation described as species that exclude all other species and dominate sites indefinitely. Plants in this category are a threat to natural areas wherever they occur because they tend to disperse widely (for example, through transport by birds or water). They are the top priority for control but control may be difficult.

Rhamnus cathartica
Common Name: Common Buckthorn, European Buckthorn Common-Buckthorn

Height: Up to 10m tall
Type of Plant: Deciduous Shrub or small tree that is fast growing and short lived
Leaves: Smooth, dark green leaves with slightly serrated leaf margins, somewhat elliptical and arranged in opposite to sub-opposite pairs along the stem. A sharp thorn can be found on the end of most branches.
Flowers: Flowers occur in the spring. They are yellowish/green, with four petals in clusters of 2 to 6 near the base of the petioles. They are small and inconspicuous.
Fruit: Produces clusters of berry-like globose black fruit in late summer and fall; although it’s mildly poisonous, birds and other wildlife eat the fruit and disperse the seeds.
Culture: Can thrive in a wide range of soil and light conditions. It is shade tolerant.
Invasion Pathway: Introduced from Eurasia to North America in the 1880s for ornamental landscaping. It was widely planted for fencerows and windbreaks in agricultural fields. The large number of seeds are spread by birds and animals.
Impacts: Habitat destruction and because it leafs out early, it is a danger to native species. It also alters the nitrogen levels in the soil. The soybean aphid, an insect that damages Ontario soybean crops, can use buckthorn as a host plant to survive the winter.
Control Measures: Physical removal, herbicides, fire, girdling

Alliaria petiolata
Common Name: Garlic Mustard

Height: 30 – 100cm tall
Type of Plant: Biennial Herb in Mustard Family
Leaves: In First Year: Leaves are dark green, cordate shaped with crenate margin edges. In Second Year: Leaves are alternate on a larger stem with somewhat doubly serrated edges. The lower leaves on the stem are broad, cordate shaped and up to 10cm across. The upper leaves on the stem start to narrow.
Flowers: In Second Year: Four white petals appear, arranged in cross shape.
Fruit: In Second Year: The fruit is erect, slender, 4-sided pod, green, maturing pale grey-brown, two rows of small shiny black seeds. Hundreds of seeds can be produced from a single plant.
Culture: Alliaria can grow in a wide range of sunny and fully shaded habitats, including undisturbed forest, forest edges, riverbanks and roadsides.
Invasion Pathway: Introduction for perceived medicinal value as a disinfectant, a diuretic and sometimes being used to treat gangrene and ulcers. It was also planted as a form of erosion control. European settlers also used it as a garlic type flavouring. Seeds can remain in the soil for several years and still be able to germinate. Hundreds of seeds produced from one plant.
Impacts: Alliaria forms dense stands, replacing native plants and has been implicated as partial cause for endangered status of our native wood poppy (Stylophorum diphyllum), American ginseng (Panax quinquefolius) and our provincial Trillium (Trillium cernuum). It is toxic to larvae of certain butterfly species that lay eggs on the plant.
Control Measures: Removal by hand, mowing or burning in early spring before flowering. Should always be bagged and burned.

Cynanchum louiseae and C. rossicum
Common Name: Dog Strangling Vine

Height: 2m high
Type of Plant: Twining Vine
Leaves: Oval with a pointed tip and grow opposite
Flowers: Pink to dark purple star-shaped flowers have five petals
Fruit: Produces bean-shaped seed pods that open to release feathery white seeds in late summer
Culture: Prefers open sunny areas but can handle some shade. More dominant in meadows or woodland edges.
Invasion Pathway: Introduced in the U.S. in the mid 1800s for use in gardens. Produces 28,000 seeds per square metre. Seeds spread by wind and new plants also can grow from root fragments
Impacts: Forms dense stands that overwhelm and crowd out native plants and young trees, preventing forest regeneration. Invading ravines, hillsides, stream banks and utility corridors. Leaves and roots may be toxic to livestock.
Control Measures: Digging is most effective. Hand pulling is not recommended as the plant will send up multiple shoots.

Vinca minor
Common Name: Periwinkle

Height: Up to 15 cm tall
Type of Plant: Evergreen herb that exhibits a trailing mat with a medium growth rate.
Leaves: Lance shaped, shiny, evergreen with a subtle white mid vein. They are opposite along stem.
Flowers: Showy blue/purple with 5 fused pin-wheel like petals and a short tubular throat that bloom in late spring.
Culture: Various soil types. Found in forests and along streams, roads and wetlands. Typically associated with residential gardens.
Invasion Pathway: Introduced as a garden ornamental and medicinal herb. It spreads by means of arching stolons, which root at the tips. Grows most vigorously in moist soil with only partial sun, but it can grow in the deepest shade and even in poor soil.
Impacts: Still sold as a groundcover which is a major concern. It spreads quickly and is a threat to native biodiversity.
Control Measures: It can be pulled, raked, or dug up, though re-sprouting will likely occur. It can also be cut or mowed in spring during its rapid growth stage.

Aegopodium podagraria
Common Name: Goutweed

Height: 2m tall
Type of Plant: Herb
Leaves: Compound leaf with serrated edges, can be non-variegated or variegated green and white, alternate
Flowers: Flat topped ‘umbrella like’ flower head with many small white flowers in late spring held above the foliage on leafy stems (which look similar to Queen Anne’s Lace).
Culture: Various habitat. Full sun to part shade. An escapee from residential gardens into forested areas.
Invasion Pathway: Goutweed seeds require recently disturbed soil and a sunny location to survive after germination. For this reason, Goutweed does not have much success reproducing by seed in forest ecosystems. However, even one established plant can create a large colony by spreading through its aggressive rhizomes.
Impacts: Forms dense patches that displace native plants.
Control Measures: Because it has limited reproductive success by seed, small patches of Goutweed can be easily controlled by digging up the plant (with careful attention given to removing the entire rhizome) or covering with a tarp or weed barrier for at least one growing season.

A reliable resource for invasive species is the Ontario Invasive Plant Council

Bulbs, Garden Design, Invasive, Perennials, Planting, Soil

Spring Flowering Bulbs

October 7, 2019 peterboroughmastergardeners 1 Comment

By Sharleen Pratt, Master Gardener

Charles Dickens said “Nature gives to every time and season some beauties of its own”. Who can deny that spring-flowering bulbs are a promise of warmer temperatures and hopeful thoughts? Knowing the bulbs will emerge from the near frozen ground helps us to get through the bitter winter. They should be planted now in order for you to be rewarded with wonderful colour in early spring. They can stay in the ground year after year. There are several varieties of bulbs to choose from. The following are some of the more recognizable ones.

Tulips are to Turkey and Central Asia. In the 1600s, they made their way to the Netherlands. Tulipmania took hold in the 1620s and tulip prices skyrocketed. A single bulb could be worth as much as an average family farm. The market collapsed in 1637, but tulips remain widely grown in the that country. Canadians liberated much of the Netherlands during the final months of the Second World War. More than 7,200 Canadians were lost in that conflict. The Dutch have gifted Canadians with 20,000 bulbs a year since that time and they are used in Ottawa’s now famous Canadian Tulip Festival every May. This year marks the 75th anniversary of liberation and the Dutch royal family will mark the celebration by thanking Canadians this year with a gift of 100,000 tulip bulbs. If you want to join the celebration, you can purchase your own Liberation75 tulips for $15.00 through the Royal Canadian Legion. By purchasing the bulbs, you will also be entitled to win a trip to the Netherlands. To place an order visit the Royal Canadian Legion.

There are hundreds of cultivars of tulips; early, mid and late blooming. They need a sunny location with soil that is well-drained and sheltered from the wind since they can be easily broken. Six weeks are needed for the foliage to die back in order to put energy back into the bulb. A rainy spring is bad for success with tulips. Some of the ‘old fashioned’ tulips are Darwin and Triumph. They are very reliable and come back year after year. Squirrels love tulips, so to deter rodents, mix tulips and daffodils together in order to get the scent of daffodils on the tulips. You can also try hen manure which comes in a pellet form. You could use barberry cuttings or crushed egg shells in and around the hole. Others have had success with plastic snakes. Also, squirrels won’t dig past their peripheral vision, so plant at least 6 – 8” deep. You could also try laying a flat board on top and remove it when the ground is frozen.

Daffodils and narcissus bloom earlier than most tulips. Spring sun is needed and they like soil that is well draining or they will rot. Oxalic acid on the bulb make them unpalatable to rodents. ‘Tete a tete’ is a mini daffodil that is very fragrant and also good for cut flowers. However, never include daffodils with other flowers in a vase as they have a sap that will cause the other flowers to wilt.

Alliums are ornamental onions. Most of the varieties bloom in June. They need free draining soil with 6 to 8 hours of sun. They make lovely dried flowers. It is best to plant alliums amongst other plants as the foliage is not desirable.

Muscari or grape hyacinths are amazing small bulbs known as minor bulbs. Snowdrops are also minor bulbs and are the first to emerge, often pushing up through the snow.

Snow crocus are an early blooming crocus and work well in a lawn as they bloom before you need to cut the grass. Dutch crocus are good for forcing and are bigger than snow crocus and tend to bloom a little later in the spring.

Beware of Scilla or Spanish blue bells! They are a small bulb and multiply prolifically, and although they are very pretty, they now sit on the invasive list. Scilla siberica is on the Highly Invasive category of this list put together by Credit Valley Conservation.

Bulbs can also be planted in pots and put in a cool area over the winter. This way, they can be brought in and forced to bloom early. Who wouldn’t be happy with a large pot of beautiful colour after a long hard winter. More information on forcing spring bulbs can be found in this article by Dugald Cameron in Garden Making Magazine.

Happy Planting!

Invasive, Links

Dog Strangling Vine

July 1, 2019 peterboroughmastergardeners Leave a comment

by Judy Bernard, Master Gardener

While taking a walk along one day along one of the lane ways along Crowe Lake, I spotted Dog Strangling Vine. It was because of the flowers that I recognized it. They are very small, 5 to 9 mm long, star shaped and pink to dark purple in colour. The vines grow 1 to 2 metres long and will twine around structures, other plants or each other. The leaves are oval with a pointed tip, 5 to 9 cm long and grow on opposite sides of the stem. The flowers develop into a bean shaped pod filled with feathery seeds that are dispersed in late summer (similar to the milkweed pod, but much narrower).

The problem with dog strangling vine is that it can form dense stands that can overcome and force out other plants. Its leaves and roots are toxic to animals. It threatens the Monarch Butterfly which will lay its eggs on the plant, but the larva cannot develop. (It’s related to milkweed, a plant necessary for the Monarch Butterfly.)

I contacted the municipality and they have no program for its control, so it’s up to the individual property owner to be aware of it and to control its spread.

The Ontario Invading Species Program has information of how to control its spread.

If you already have some on your property, check out Best Management Practices. This also is from the Ontario Government.

Garden Design, Invasive, Perennials, Planting

Beware the Vigorous Plant!

February 11, 2019 peterboroughmastergardeners 1 Comment

By Suzanne Seryck, Master Gardener

Being the fairly recent owner of a small city garden, I find I no longer have the space for plants that either do not behave, need too much deadheading or pruning, spread too quickly becoming invasive, need to be staked or I’ve simply grown tired of. At least 90% of my garden is full of either fruit trees, shrubs, fruit bushes, perennials or raised vegetable beds. The remaining 10 or so percent contains a patio and a very, very small lawn that my husband tells me has to stay! So needless to say if I buy any new plants I have to give an existing plant or two away (thank heavens for plant sales).

I have a few plants in mind that I am considering replacing this spring so I have spent the last week or so looking through bulb and plant catalogues to see what is new this year. Catalogues are a great place to see what is new and exciting and also to fill the gardening void that generally happens this time of the year. However, I have heard both good and bad stories regarding plants purchased from these catalogues, so it is very much a personal choice. What I did notice though were the many different terms given to what I would describe as an invasive or ‘buyer beware’ plant, especially if, like me, you do not have a large garden.

Allium were described as ‘carefree’. However, if you have ever tried removing hundreds of allium bulbs from a perennial bed that have self-seeded over many years ‘carefree’ is not a term I would immediately think of.

‘Vigorous’ is a term often used in these catalogues, which could mean either that the plant is strong, robust and grows well (which we would all like) or more likely that the plant grows very quickly and will take over your entire garden in a very short time. Examples of ‘vigorous’ plants include false sunflower (Heliopsis helianthoides), knotweeds (Persicaria) and orange trumpet vine (Campsis radicans).

Baby’s breath (Gypsophila) is listed with the description that it ‘readily fills gaps’, whereas bee balm (Monarda) is described as ‘multiplying quickly’.

Lily of the valley (Convallaria majalis), need I say more! I actually inherited this plant in my shade garden and I think I could be digging it out for a good few years. I really do love this plant, but it has to be in the right location and in a bed all by itself. Lily of the valley is described in one catalogue as ‘creating a carpet of flowers’ and in another catalogue as ‘growing fearlessly among tree roots’.

But I think the term most often used to describe a plant that might become invasive in these catalogues is ‘naturalizing’. When I think of naturalizing I think of beds or daffodils or bluebells, but then I am English so that might explain why. Plants included in this category are masterworts (Astrantia), mountain fleece (Persicaria amplexicaulis), false sunflower (Heliopsis helianthoides) and meadow rue (Thalictrum flavum).

Being an avid gardener, some may even say obsessive, there are not many plants that I do not like and all of the plants listed above I have at one time or another grown, and still do. But gardening with only a limited amount of space has changed the way I look at and select plants.