This is a link to Prohibited Invasive Species in Ontario, illegal and presumed not commercially available, but added to the list below in the interest of making it comprehensive.

This is a link to Plant Me Instead, published by the Ontario Invasive Plant Council, which offers alternatives.

The list below of invasive, non-native plants includes ones that are sold by garden centres despite their negative impact on the environment. Those ones are in bold. Do NOT BUY! The ones marked with an asterisk are the most aggressive, but some, like Phragmites, are banned and unlikely to be found in garden centres.

Acer platanoides* Norway Maple

Acer ginnala Amur Maple

Aegopodium podagraria* Bishop's Goutweed

Aesculus hippocastanum Horse-chestnut

Ajuga reptans* Creeping Bugleweed

Berberis thunbergii Japanese Barberry

Betula pendula* European Birch

Butomus umbellatus Flowering Rush

Cabomba caroliniana Fanwort

Campanula rapunculoides Creeping Bellflower

Celastrus orbiculatus* Oriental Bittersweet

Convallaria majalis* Lily-of-the-Valley

Coronilla varia* Crown Vetch

Cynanchum louiseae* Black Dog-strangling Vine or Black Swallowwort (restricted in Ontario)

Cynanchum rossicum* Dog-strangling vine or Pale Swallowwort (restricted in Ontario)

Eichhornia crassipes Water Hyacinth

Egeria densa* Brazilian waterweed (banned in Ontario)

Elaeagnus umbellata* Autumn Olive

Elaeagnus angustifolia Russian Olive

Euonymus alata Winged Euonymus

Euonymus europaeus Spindle-tree

Euonymus fortunei Wintercreeper

Euphorbia cyparissias Cypress Spurge

Frangula alnus* Glossy Buckthorn

Impatiens glandulifera* Himalayan Balsam

Iris pseudacorus Yellow Iris

Galium mollugo White Bedstraw

Hedera helix* English Ivy

Hemorocallis fulva Orange Daylily

Hippophae rhamnoides Common Sea Buckthorn

Hydrilla verticillata Hydrilla (banned in Ontario)

Hydrocharis morsus-ranae European Frog-bit

Lamiastrum galeobdolon Yellow Archangel

Lonicera × bella Bell's Honeysuckle

Lonicera japonica* Japanese Honeysuckle

Lonicera maackii Amur Honeysuckle

Lonicera morrowii Morrow's Honeysuckle

Lonicera tatarica* Tartarian Honeysuckle

Lycopus europaeus* European Bugleweed

Lysimachia nummularia Creeping Jenny, Moneywort

Myriophyllum aquaticum* Parrot feather (banned in Ontario)

Miscanthus sinensis Chinese Silver Grass, Zebra Grass

Miscanthus sacchariflorus Amur Silvergrass

Morus alba* White Mulberry

Nymphoides peltata Yellow Floating Heart

Pachysandra terminalis Japanese spurge

Phragmites australis subsp. Australis* European Common Reed (restricted in Ontario)

Pinus sylvestris Scots Pine

Pistia stratiotes Water Lettuce

Populus alba White Poplar

Reynoutria japonica var. japonica* Japanese Knotweed (restricted in Ontario)

Rhamnus cathartica Common Buckthorn

Robinia pseudo-acacia Black Locust

Rosa multiflora* Multiflora rose

Scilla siberica Scilla

Sedum acre Mossy Stonecrop

Salix alba White Willow

Salix x rubens Hybrid Willow

Stratiotes aloides* Water Soldier (banned in Ontario)

Syringa vulgaris* Common Lilac

Trapa natans* European water chestnut (banned in Ontario)

Viburnum opulus Guilder Rose, European Cranberry

Vinca minor* Common Periwinkle

Viola odorata Sweet violet