The Joy of Landscaping

A Gardening Blog

Invasive Plants: Avoid These Very Bad Boys!


The joy of helping the environment.

My last blog discussed the rose rosette disease that was primarily introduced into the U.S. with introduction of an invasive plant, the multiflora rose. It got me riled up enough to help get the word out about invasives in general.

The first issue is defining "invasive". We typically describe plants as invasive when they start taking over our gardens through excessive growth and spread. While this can be a characteristic of an invasive plant, especially when it is planted next to a natural landscape, the primary definition of a plant that's on, for example, a state DNR's list of invasive plants, is: a non-native plant that takes over natural habitats or is destructive to the ecosystem. Often this occurs by birds transferring their seeds, or the seeds dispersed by wind.

The scientific community is acutely aware of the severe destruction caused by the plants listed below to natural habitats, and many long time gardeners have experienced their evil ways in their own gardens. But to further emphasize just how bad these plants are, DO NOT EVEN THINK ABOUT PLANTING THESE PREDATORS:

Really, really bad plants

  • Bindweed/Perennial Morning Glory (Convolvulus arvensis) - and some species of Ipomoea
  • Canada Thistle (Cirsium arvense, C. setosum, C. incanum, Serratula arvensis)
  • Cogon Grass, (Imperata cylindrica, Imperata arundinacea, Lagurus cylindricus)
  • Knotweed (Reynoutria japonica, R. sachalinensis, Reynoutria x bohemica, Fallopia japonica, F. sachalinensis, Fallopia x bohemica, Polygonum cuspidatum, P. sachalinenesis, Polygonum x bohemica)
  • Kudzu (Pueraria montana, P. lobata)
  • Oriental Bittersweet (Celastrus orbiculatus)
  • Mile-a-minute (Persicaria perfoliata. Polygonum perfoliatum)
  • Mulitflora Rose (Rosa multiflora)
  • Porcelain Berry (Ampelopsis brevipedunculata)
  • Purple Loosestrife (Lithium salicaria)
  • Scotch Broom (Cytisus scoparius)
  • Yellow Iris (Iris pseudacorus)

Notice that most of these are vines? If there’s one category of plants that should be researched before buying, it’s the vine!

Invasives you might not know about

Fortunately, most of the plants above have been banned for sale, even though their effects are still being seen across the landscape. However, some other very invasive plants are still being sold, with many people not even aware of their detrimental aspects. Some, like Barberry, Winter Creeper and Silver Grass, have been very popular in home gardens for years. I admit to having planted some of these myself, before “knowing better”. Fortunately, more and more states are adopting regulations banning or regulating many of these, e.g. New York state in 2015, but it’s still up to us to take the time to know more about what we are planting in our yards. Do not assume just because something for sale is in your local gardening center or in a nationwide plant catalog that it’s all good.

So, if you want to protect the environment (and in some cases, keep your sanity in your own yard), add these to your list of plants to avoid:

TREES

  • Chinese Tallow Tree/Popcorn Tree (Triadica sebifera)
  • Norway Maple Tree (Acer platanoides)
  • Princess Tree (Paulownia tomentosa)
  • Sycamore Maple (Acer pseudoplatanus)

SHRUBS

  • Border Privet (Ligustrum obtusifolium)
  • Chinese Privet (Ligustrum sinense - including the variegated variety)
  • Barberry (Berberis thunbergii)
  • Burning Bush (Euonymus alatus)
  • Common Buckthorn (Rhamnus cathartica)
  • Autumn Olive (Elaeagnus umbellata)
  • Winter Creeper (Euonymus fortunei)

BarberryMiscanthus


Berberis thunbergii and Miscanthus sinensis

PERENNIALS

  • Cypress Spurge (Euphorbia cyparissias)
  • Garden Loosestrife (Lysimachia vulgaris)
  • Leafy Spurge (Euphorbia esula)
  • Lesser Celandine (Ficaria verna/Ranunculus ficaria)

VINES

  • English Ivy (Hedera helix)
  • Japanese and Chinese Wisteria (Wisteria floribunda, Wisteria sinensis)
  • Japanese Honeysuckle (Lonicera japonica), Amur Honeysuckle (Lonicera maackii), Tatarian Honeysuckle (Lonicera tatarica), Morrow’s Honeysuckle (Lonicera morrowii), Fly Honeysuckle (Lonicera x bella) - when in doubt, avoid plants named “Lonicera”!
  • Sweet Autumn Clematis/Japanese Virgin’s Bower (Clematis terniflora)

GRASSES

  • Bamboo (especially running varieties)
  • Chinese Silver Grass (Miscanthus sinensis)

I'll discuss substitutes for some of these in my next post so help is on the way!