Want to add a plant to our list? Just email us with the name of the plant and your experience or reason for placing it in the aggressive or invasive category.

Balfour's touch-me-not

  Impatiens balfourii
This is a 2-foot-tall annual that self-seeds like mad. I couldn't resist its purple, pink, and white snapdragon-like flowers.   But this superabundant shade plant soon took over the spaces and sprouted up in every nook and cranie… I was soon yanking out the little seedlings by the bucketful.

I learned to cut it back just before it went to seed and had it somewhat under control by the third year.

Bishop's Weed, also known as Ground-elder

  Aegopodium podagraria   Zones 4-9   Variegatum being the most showy and desireable foliage for shade gardens… but beware… it is a beautiful bully that will carry on their battle for dominance.
Just look at this root structure and you'll know what a problem this plant can be if not controlled and contained. They will create a sprawling tapestry and choke out other plants, weeds included!

I used it in a narrow bed on the side of the house that didn't get much sun or rain, and where nothing else would grow. It looks quite lovely and required a good edging twice a year to keep it out of the lawn.

Hidcote comfrey

  Symphytum
'Hidcote Blue'   Zones 4-7 is a free-flowering, wildly prolific ornamental herb. My daughter only planted 3 small plants(3-pak size) and by the third summer… it was galloping thru her herb bed, like a sea of blue on the shaded side of her herb garden.   We're pretty sure it's galloped down that tree line by now and is probably filling in the shaded area between those trees and the house!

Pachysandra

  Pachysandra terminalis
´Green Carpet´ is deservedly one of the most widely used ground covers. It is handsome and foolproof, thriving even in the dense shade of evergreens! Try it along shady walks, in enclosed courtyards, and on steep terraces in either partial sun or shade. It is aggressive, a good spreader and a desireable ground cover in the right place where you don't want to grow other perennials.

Purple Loosestrife

Lythrum salicaria Loosestrife family (Lythraceae)
Invasive and on ´weed watch lists´ in most parts of North America.   Purple loosestrife adapts readily to natural and disturbed wetlands.   As it establishes and expands, it takes over, pushes out and replaces native grasses, sedges, and other flowering plants that provide a higher quality source of nutrition for wildlife.   The highly invasive nature of purple loosestrife allows it to form dense, homogeneous stands that restrict native wetland plant species, including some federally endangered orchids, and reduce habitat for waterfowl.

Each flower spike can produce up to 300,000 seeds; it also reproduces new shoots from its roots.   Efforts are underway to reduce loosestrife populations by releasing special beetles that feed on the plant's roots and leaves.   This native of Eurasia is considered a noxious weed, and I implore you not to purchase and plant it unless it is guaranteed to be sterile!

Sweet Woodruff

  Galium odoratum     Aggressive in shade.
From ´Over the Fence´ in Cedar, Michigan… a gardener warns that Sweet Woodruff can run rampant in cultivated beds but also has completely taken over the forest floor in the Whaleback Nature Area, which is on the Leelanau Peninsula of Northwest Lower Michigan, and crowded out all of the native wildflowers, such as trillium, jack in the pulpit, dutchman's breeches, and lady slippers. Apparently, the sweet woodruff moved in from a nearby home garden. It looks lovely and smells good, but what a sad loss of the truly native plants. Gardeners who live in or near woods need to be particularly careful that this "vigorous spreader" does not get out of control.

Tovara "Painter's Palette'

  Persicaria virginiana
A 2 foot tall neat and mounding perennial. Its mottled green, white, and red leaves make it a standout in the shade, and in October, it further adorns itself with sprays of red flowers.

Best if contained in a flower bed under a large tree, but keep it in check!

Yellow Archangel

  Lamiastrum galeobdolon
Zone 4-9   "Evergreen except in the coldest climates. Yellow Archangel sports handsome silver-marked foliage that grows 12-18 inches high. Tolerates adverse conditions. Yellow flowers from late spring into early summer."   What this nursery description fails to mention is that it spreads like a wildfire, not only on the ground, but look out Pine Trees! I planted some as a ground cover in a fairly large garden bed to give some privacy to our backyard, with 5 blue spruce pines.

By the third year it was climbing the pines and I started ripping it out… using a hand claw to divest the roots, only to have it become more energized (new growths started from the roots I didn't get)! I eventually had to resort to chemical warfare to bring it under control.