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I am always amazed when I see known invasives being sold at garden centers, online, and in catalogs. Here are 10 silent invaders you should never bring home to grow in your yard—plus, some substitute plants to grow instead.
Autumn Olive
Autumn olive (Elaeagnus umbellata) is often sold in wildlife packages or for erosion control. Birds do love its berries, which is one way they spread. Able to grow rapidly in sun and shade, their roots alter the soil chemistry around them to keep other plants from germinating nearby, and they outcompete and quickly displace native species.
Substitute plants: Native Physocarpus or Viburnum both offer colorful fall foliage and berries for birds and other wildlife.
Bishop’s weed (Aegopodium podagraria), also known as goutweed, is my arch-enemy. The variegated leaf type was growing on my property when we moved in 38 years ago, and even though we mow it and pull it up, it still comes back.
I am always appalled when I see it for sale. It is quite pretty, grows in sun or shade, and is totally bulletproof, so I can understand why people buy it. Don’t!
The extremely invasive green type keeps making its way from my neighbor’s house via seeds the birds drop. I spend a lot of time every spring and summer digging up its brittle roots, which tend to snap off. Leaving even a tiny piece behind causes it to resprout soon after. We have tried smothering large sections of it with black plastic, but it manages to return. They say the only way to be rid of it is to move!
Substitute plants: Native foamflower (Tiarella cordifolia) or wild geranium (Geranium maculatum) for shady areas.
Bradford Pear
Ugh! It may look pretty, but the awful Bradford pear (Pyrus calleriana)—also called Callery pear—has been sold widely as a cheap ornamental landscape tree. Even though it is self-sterile, it can cross-pollinate with other types of callery pears, and those offspring have proven to be invasive, escaping to forest areas, dominating the landscape, and shading out all other growth.
Substitute plants: They are such a problem in South Carolina that Clemson University offers up to 5 free native replacement trees—including oaks, maples, hornbeam, river birch, and magnolia—to homeowners who cut down their Bradford pears.
More substitute plants include native dogwood, redbud, and serviceberry. All provide spring bloom, fall color, and berries for wildlife.
Burning Bush
Burning bush (Euonymous alatus) is another invasive I often see for sale. People can’t resist its flaming red fall foliage even though it is on the invasive species list in many states. This is another plant that came with my house. The former owner made sure to tell me all about how beautiful it was and to never cut it down. Needless to say, when we learned of its invasive nature, we cut it immediately and continue to battle with it resprouting all around the property and into the neighboring woods. Easy to spot in the fall, we diligently patrol the woods around us and yank those suckers out.
Substitute plants: Native Fragrant Sumac (Rhus aromatic) or Nannyberry (Viburnum lenatgo). Both have colorful fall foliage and berries for the birds.
Buddleia (Butterfly Bush)
Butterfly bush (Buddleia) is a favorite of ours for the butterflies and pollinators it attracts. I was surprised to see it on the invasive list since it never reseeds in my area. We deadhead as the blossoms fade, so seeds don’t get a chance to develop, but it is easy to miss one or two, especially if the bush is large and full of flowers. Unfortunately, this non-native not only outcompetes native plants but also reduces the native’s reproductive success, eventually harming the native’s populations.
If you already own a Buddleia, you don’t have to remove it. But prune it severely when the flowers have faded so it can not spread its seeds. Some Butterfly Bush cultivars are marketed as being sterile or low-fertility. Unfortunately, many of these plants will revert to their original.
Substitute plants: Plant one of the many gorgeous native plants that attract and support butterflies. For sunny yards, try Sweet Pepperbush, also called Summersweet (Clethra alnifolia) which attracts butterflies as well as birds, including hummingbirds! Another choice is Buttonbush (Cephalanthus occidentalis), a flowering shrub that is deer-resistant and a good nectar source that attracts butterflies and pollinators to your yard.
If you’re into purple flowers, consider the Gayfeather (Liatris spicata), which attracts bees, hummingbirds, and butterflies. And if you wish to support Monarch butterflies, plant the native Milkweed (Asclepias tuberosa), which not only supports adult butterflies but also the American butterfly baby (that is, caterpillars).
Chameleon Plant
Many plants we’re attracted to buying are beautiful. The chameleon plant (Houttuynia cordata) is no exception. Native to Southeast Asia, this ground cover has very attractive, multi-colored leaves and, like many ground covers, spreads by underground rhizomes—fast! If you try to weed it out those brittle rhizomes break and any scrap left behind will just resprout, similar to bishop’s weed. It grows in sun or shade and likes moist soil.
Substitute plants: Native heuchera, tiarella, or a showy hybrid of the two called heucherella.
Dame’s Rocket
Resembling phlox when it blooms in late spring, Dame’s rocket (Hesperis matronalis) seeds can be found in wildflower meadow mixes, even though it’s not a native plant. The blooms are fragrant and pastel-colored.
A biennial, Dame’s Rocket spreads by seed to take over roadsides and sunny woodland edges. If you see it for sale, don’t bring it home to plant in your cottage garden, or it will soon be the only thing growing in your cottage garden.
Substitute plants: Natives such as anise hyssop, phlox, or monarda.
English Ivy
Often sold as a ground cover or climber, English ivy (Hedera helix) quickly scampers up trees or buildings or crawls across the ground, smothering anything in its path. It roots easily wherever the stems touch the ground. It can reach 90 feet high into the forest canopy, blocking sunlight from reaching tree leaves, and eventually killing the trees. It is best grown as a trailing plant in a windowbox or hanging basket.
Substitute plants: Consider climbing hydrangea for vining growth and wild ginger as a ground cover.
Lily-of-the-Valley
These flowers may look dainty and smell sweet, but Lily-of-the-valley (Convallaria majalis) has an extremely aggressive nature and soon forms large colonies, crowding out all its neighbors if planted in a mixed flower bed. It is also toxic to people and pets.
Substitute plants: Native bunchberry, wintergreen, or tiarella as shady groundcovers. For early blossoms, try snowdrops.
Yellow Flag Iris
Yellow flag iris (Iris pseudocorus) is sold as an ornamental for wet locations around ponds and streams. However, it forms dense colonies, choking out native shoreline plants. All parts of the plant are poisonous and can cause skin irritation.
Substitute plants: Blue flag iris, yellow pond lily, or pickerelweed.
When plant shopping, be sure to do your homework so you don’t add a plant to your landscape that you will later regret. If a well-meaning friend wants to give you any of these troublemakers, say no!
I don't know anything about Autumn Olive. You say they poison the ground and nothing will grow around them. The same is true of Black Walnut trees. Do you propose cutting them down?
I have always had burning bushes with no problems. They are carefree and beautiful and the birds do love the berries. They are one of the best reminders of fall. I will keep them.
Don't be so quick to ax the butterfly bush. There are sterile varieties available, as well as, apparently, some native North American ones. And the pollinators love them. The one I have in a pot on my patio hasn't given rise to any seeds or spread and is now in its third year.
I'm battling Weeping Cherry. We bought our house about 17 years ago. It looked pretty under the kitchen window next to the deck. Now it is *everywhere* in our yard! Cutting the pieces we see isn't helping. The main trunk is super hard. Help is appreciated!
Gout weed is impossible to get rid of, was here when I bought the house. Japanese knotweed is aggressively invasive, but somehow years ago a neighbor thought it cute and actually planted some, and steadily the underground root system made its way onto my property and spread no matter how we chop, dig, etc. I'm fond of the several Rose of Sharon that I planted, but didn't realize that little sprouts appear all around the bushes and must be pulled out regularly or it takes over the area.
Thank you for this important article. When we moved to our house 10 years ago, we had 5/10 of these plants on our property (plus Trumpet Vine and an untrained Wisteria). We have only been able to eliminate the Burning Bush. If we move again and I see Goutweed on the property, that will be a deal breaker - It is the bane of my existence!!! I wish I had known what a problem it would pose as I unknowingly spread it to other parts of the yard by moving and dividing other plants.
You mention Wintergreen as a substitute plant, but I think it is considered invasive in many states. I believe it makes the invasive plant list in Missouri.
When confronted, years ago, with thistle plants in our mowed area I found that pouring undiluted vinegar on the center of the plants killed not only the above round portion, but the roots as well. Best when used on dry soil as it becomes the go-to-moisture for the root system. This idea may well be effective with other root systems. You will have a brown spot, but the native grasses eventually filled in the space. Hope this helps.