Invasive plants are taking hold of our natural areas, choking out other plants and related animal life. Our job as gardeners is to keep invasive plants out of our yards to avoid any possible spread and grow beneficial plants instead.
For help researching plants, I have listed some online plant databases here.
How Gardeners Can Help Fight Invasive Plants
GROW NO HARM
Prevention is key.
As gardeners and caretakers of the earth, this is our first responsibility: grow no harm.
Years ago the topic of invasive plants rarely came up in garden how-tos but as things are today, invasiveness should be our first concern when selecting plants.
Our entire eco-system depends on natural checks and balances between plants and animals.
This is the circle of life: biodiversity and sustainability.
When invasive plants take over, our natural habitats are altered or gradually destroyed.
I didn’t think twice about this stuff when I started gardening many years ago, and now it’s the center of my garden choices.
Invasive plants gradually choke out adapted, non-aggressive plants and the animals they have co-evolved with.
Without predators or natural containments, these thugs are gradually destroying our natural areas.
The bee gets the pollen or nectar, the flower is pollinated. It’s win win.
So What Does This Have to Do With Home Gardening?
What we grow in our gardens is what we grow everywhere.
There are a lot of us gardeners! Together we have tremendous power to influence the gardening industry and decide how our gardens will or will not contribute to the well-being of the earth.
Many invasive species we struggle with today were introduced by humans—either intentionally or incidentally, or by wind or animals.
And, no matter how much we try to contain things or think we can control it in our own yards, plants can always spread.
This could be by pollination, natural propagation such as a bird pooping out a seed, roots spreading to neighboring yards, disposal of the plant or clippings in yard waste which ends up growing elsewhere, and countless other ways. Most often it is done innocently or unknowingly, but either way, it is a problem.
If we grow it in our gardens we have to assume it can and will be released into nature.
Get to Know Your Local Invasive Species
As a gardener, I encourage you to look up invasive species resources for your region and get familiar with the major players. In many cases, borders on a map are meaningless: some of these problems cover vast areas of our continent.
Have you got any invasive plants growing in your garden?
I do! And removing them is an ongoing project.
A big clue is often if the plant is both hardy and fast-growing or spreads rapidly. Anything fast or really easy to grow can spell trouble.
The most startling thing is that while environmental and conservation groups are battling these invasive species if/as funding allows (which fluctuates depending on the political parties in charge), a bunch of these plants are still sold at plant nurseries. As informed consumers we can help stop this.
Not all invasives in natural areas are caused by gardeners of course, but over the years we have certainly played a role.
Using ‘native plants‘ is part of the solution. But beware that it’s not that simple.
Just because it’s labelled native for your region does not mean it is suited to your specific garden climate and growing conditions. And some native species can be aggressive growers too. It’s always about the right plant in the right place.
On the flip side, not all introduced species, hybrids, cross-breeds, and cultivars are invasive—not by any measure. But they may be sterile or infertile and not provide any benefit to birds, bees, butterflies, and so on. So it’s worth researching plants before purchasing.
Ultimately what we need are non-invasive, non-aggressive plants that fit our climate and growing conditions and have a symbiotic relationship with other non-invasive living things. Grow to restore those natural checks and balances as much as we can.
It’s a lot to consider but the reward is a vibrant, thriving garden that does no harm. Or at least helps prevent further invasion.
Wait! Before You Plant…
Be sure any plants you choose:
- Are recommended for your plant hardiness zone.
- Are not invasive in your area.
- Are suitable for your growing conditions including sun, soil, water, and wind.
- Contribute to biodiversity by providing food, nectar, or habitat for wildlife.
- Will not be too big for the space at mature size.
You can read more ecological gardening tips here.
Southern Ontario Invasive Plants and Alternate Choices
Invasive plants can be terrestrial or aquatic including annuals, perennials, trees, shrubs, and vines.
These lists show common invasive plants for southern Ontario, Canada and surrounding regions and provides some alternative plant choices.
I have compiled these lists from the resources listed here. They are suggestions that you need to research before acting on.
Again, be sure whatever you choose is non-invasive and (preferably) non-aggressive, is well-adapted for your area and growing conditions, and has a symbiotic relationship with local wildlife.
Groundcovers, Wildflowers, and Grasses
Pale Purple Coneflower
|Starry Solomon’s Seal
Trees, Shrubs, and Vines
|Ruby Lace Honeylocust
Gleditsia triacanthos var. inermis
L. x bella
|Native Bush Honeysuckles
|Honeysuckle – Japanese Vine
Hydrangea anomala spp. petiolaris
Lonicera x heckrotti
Viburnum lentago, V. lantanoides and others
Wild Black Current
Rosa carolina, R. virginiana
|Sugar, Silver, and Freeman Maples
Acer saccharum, A. saccharinum, A. xfreemanii
Clematis x jackmanii
Morella (syn. Myrica) pensylvanica
|Downy, Smooth, and Canada Serviceberry
Amelanchier arborea, A. laevis, A. canadensis
|Yellow Floating Heart
|Fragrant Water Lily
Cardinal Flower (not aquatic)
Northern Blueflag Iris
|Common Mare’s Tail
Additional Non-Invasive Alternatives
|Canada Waterweed Elodea canadensis
|Common Arrowhead Sagittaria latifolia
|Dense Blazing Star Liatris spicata
|Dwarf Hairgrass Eleocharis acicularis
|Golden Alexanders Zizia aurea
|Great Blue Lobelia Lobelia siphilitica
|Lady Fern Athyrium filix-femina
|Maidenhair Fern Adiantum aethiopicum
|Prairie Smoke Geum triflorum
|Red Oak Quercus rubra
|Shrubby Cinquefoil Dasiphora fruiticosa
Want to grow your own oak tree?
Includes tips on how to choose viable acorns from a species suited to your growing zone.
Can Be Invasive in Natural Areas
|American Wisteria Wisteria frutescens
|Bohemian Knotweed Reynoutria × bohemica
|Brazilian Elodea Egeria densa
|Callery Pear Pyrus calleryana
|Chocolate Vine Akebia quinata
|Common and Chinese Privet Ligustrum vulgare, L. sinense
|Dog-strangling Vine (black and pale swallowwort) C. louiseae and C. rossicum
|Giant Knotweed Reynoutria sachalinensis
|Guelder Rose/ European Cranberry Viburnum opulus
|Hydrilla Hydrilla verticillata
|Japanese Hedge Parsley Torilis japonica
|Japanese Knotweed Reynoutria japonica
|Japanese Lilac Syringa reticulata
|Jetbead Rhodotypos scandens
|Kudzu Pueraria montana
|Lamium spp. Dead nettles
|Pachysandra Pachysandra terminalis
|Parrot Feather Myriophyllum aquaticum
|Saltcedar/Tamarisk Tamarix ramoisissima
|Phragmites Phragmites australis subs. australis
|Reed Canarygrass Phalaris arundinacea var. picta
|Siberian Peashrub Caragana arborescens
|Spreading Hedge Parsley Torilis arvenis
|Sycamore Maple Acer pseudoplatanus
|Tree-of-Heaven Ailanthus altissima
|Water Chestnut Trapa natans
|Water Hyacinth Eichhornia crassipes
|Water Soldier Stratiotes aloides
|White Mulberry Morus alba
|Winter Aconite Eranthis hyemalis
Ontario Invasive Plant Council | Ontario non-profit tackling invasive plant issues
Grow Me Instead: Beautiful Non-Invasive Plants for Your Garden
A Guide for Southern Ontario (PDF format)
Grow Me Instead: Beautiful Non-Invasive Plants for Your Garden
A Guide for Northern Ontario (PDF format)
In the Zone | Southwestern Ontario | Grow a healthy woodland, wetland or wildflower garden designed to help Carolinian wildlife thrive.
- Learn what’s invasive in your region.
- Remove these invasives from your garden and dispose of them without risk of regrowing.
This guide shares how to remove specific species.
- Watch for invasive plants in nurseries and report them.
- Support local conservation efforts.
~Melissa the Empress of Dirt ♛