As we all try to help pollinators and save our besieged planet, it pays to know what not to plant as well as what to plant. Sadly, not everything on offer at the local nursery is a safe choice. While they may look great in our gardens, some plants selfseed surreptitiously into nearby fields and woods as fast and as thoroughly as dandelions. Invasives greatly accelerate native species extinction, so it helps to avoid adding to the problem. Do you know which common flowers and shrubs are considered invasive?
Don’t feel guilty if you discover you have a few in your own yard — most of us do. Over time though, think about replacing them with safer choices. Check out these suggestions to see what you could swap in for a similar effect.
In each paired set of images below, a safer alternative is pictured next to the invasive for easy comparison. Use the little arrows to swipe up and down or left and right. Additional options are also provided. If you wish to jump around, here’s a list of the invasives covered in this article:
Plant Japanese maple or Fothergilla, Not Burning Bush
We all love the cranberry hues of burning bush (aka winged eunonymous) at Thanksgiving time, but its berries disperse far and wide, especially into woodlands where it out-competes everything else. Being toxic to mammals, eunonymous contributes to the starvation of deer herds by displacing the native shrubs they depend on to survive.
Why not choose Japanese maple instead? There are dozens of cultivars. Many are dwarf or medium-sized with spectacular red color. There are sure to be several that will fit your needs.
Another good choice is fothergilla, especially dwarf cultivars under 5 feet. Fothergillas have creamy “bottlebrush” flowers in spring and turn brilliant orange-red in fall.
An especially nice fothergilla is Blue Shadow. It has powder-blue summer foliage with excellent fall color. I love this one but it’s hard to find this year right now. I’m hoping it will be available again soon.
Other choices for red fall color include viburnums like Brandywine and cranberry viburnum; various sumacs; and purple smoke tree. They exhibit lush burgundy tones.
Go for Shasta Daisy, Not Oxeye
There’s no denying a field of oxeye daisies in bloom is breathtaking to behold. It looks so natural, yet that perception is far from the truth. Oxeyes are an introduced species with a prolific seeding habit, especially on lean soil in already-fragile ecosystems. They quickly form dense monocultures, choking out less aggressive plants.
In Pennsylvania, oxeyes are considered noxious weeds, often mingling with dandelion and chicory in roadsides, gravel drives and fallow fields, even sprouting from pavement cracks. This is one tough plant.
It’s far smarter to plant a more manageable variety. Shasta daisies fit the bill nicely, with their fresh faces and handsome foliage, as do any number of mum-like annuals, echinaceas and rudbeckias.
There are even doubles and soft yellow cultivars out now, like Banana Cream II. These are especially suitable for smaller suburban plots, and they can take richer, more humusy soil and a bit of shade.
Or try fleabane, a dainty native annual wildflower with thin frilly petals. Some years it self-seeds a fair amount, but most years it proliferates modestly at best. It is not aggressive and is easily weeded out if need be. It has a similar carefree habit and looks best in an informal setting.
White coneflowers are another possibility. Fragrant Angel, Pow Wow White and Snowcone are three good choices.
It’s worth mentioning that Shasta daisies are somewhat short-lived perennials, especially in clay soil with cold wet winters. Since they don’t spread, you will need to replace them every couple of years. Deadheading helps extend their bloom time considerably.
Populate with Phlox, Not Dame’s Rocket
Some people erroneously call Dame’s Rocket (Hesperis matronalis) “wild phlox” because that’s exactly what it looks like in spring, painting roadsides and meadows in its pink and white glory. (Not sure what you’ve got? Dame’s Rocket has four petals; phlox have five.)
This European escapee is less of a problem than some since it goes dormant early in the season. But it still displaces plenty of native vegetation where it establishes. So pick it– or pull it– for a bouquet!
If you crave the look and scent of Dame’s Rocket in spring, try woodland phlox, fragrant pinks, or the medium-tall early-flowering cultivar Minnie Pearl. For similar lavender-pink color and fragrance, Princess from the Fashionably Early phlox series is a great choice.
A big bonus is that both of these cultivars bloom early and go on for much longer than Dame’s Rocket without worry of self-seeding. And do consider regular tall garden phlox regardless. They are true workhorses for color and fragrance all summer long.
Red Chokeberry, not Japanese Barberry
If you already have an older variety of Japanese barberry (Berberis thunbergii) on your property you can try shearing it to reduce berry set. Some of the newer hybrids produce very few berries, like Red/ Orange Rocket. Several of the purple- and gold-leaved varieties are also close to sterile. But older varieties can be really prolific seeders.
Another similar Asian invasive to avoid is pyracantha, or firethorn.
Instead, either our native red chokeberry, or winterberry, a type of deciduous holly, are excellent alternatives. While their foliage is not as dense or colorful as barberry, their fruit production provides excellent winter interest and food for winter bluebirds, robins and waxwings.
If you plan to buy a barberry, be advised that after September 2023, most Japanese barberries will be illegal to sell in Pennsylvania. Exceptions will be four new sterile cultivars which are just now being introduced in the trade. Check your local nursery.
Japanese barberry is especially bad in the wild because its thickets are ideal breeding grounds for ticks, contributing to tick-borne diseases like Lyme. It’s toxic to deer also. On the other hand, our native barberry (berberis canadensis) is relatively scarce, well behaved in woodlands and not an issue. (It’s not available commercially.)
Choose Beautybush, not Porcelain Berry
Porcelain berry or Amur peppervine may be lesser known, but it’s a monster when left to its own devices. With unusual turquoise-blue fruits on an aggressively growing vine, it was introduced from Asia in the 1870’s for its ornamental potential. Today it is invasive throughout the entire Northeast US, including Pennsylvania. While it’s not quite as bad as mile-a-minute vine, it still swamps everything it encounters including full-size, mature trees. Yikes.
Fortunately there are better choices!
Callicarpa is one, or Beautyberry. All beautyberries sport pink, vivid purple, or white fruits in fall against bright yellow foliage. Our native form, C. americana, has puce-purple clusters of berries at intervals on the stems. Non-native Asian hybrids have more berries and come in more colors.
There is some debate as to whether the non-natives will eventually become invasive in the U.S., but for now they are not classified as such. If you are concerned about it, then it’s best to stick with our native C. americana species.
A popular hybrid called Pearl Glam has magenta berries; Purple beautyberry has, well, you guessed it. While both are vigorous growers they can take hard pruning to keep them reined in.
Viburnum Brandywine is another option, sporting white flowers in spring and clusters of pink berries in fall which turn denim blue. Brandywine’s lovely fall foliage runs the gamut from yellow to burgundy and is ever-changing.
Try Chaste Tree, not Butterfly Bush
You probably already know butterfly bush (Buddleia, originally from Asia) is invasive. But did you know how invasive? A single bush can produce over 100,000 seeds per season. Some estimates of mature shrubs surpass a million seeds! And here’s the kicker — no butterfly uses it as a host plant. The fact that butterflies just can’t leave it alone for its nectar has been relentlessly exploited as a marketing ploy to sell tens of thousands of bushes for years now. The result? Butterfly bush is out of control in over 20 states, with no sign of slowing.
Yes, it’s true, butterflies do adore it, but they love other plants equally well without the invasiveness factor. So give this some thought.
There are lots of alternatives to attract butterflies. If you like lavender, Chaste Tree (Vitex) is a great choice for a hot sunny spot. Chaste Tree does require very well-drained soil, especially in zones 5 and 6. So give it full sun and a gravelly lean matrix. A mature Chaste tree will give your garden a distinct Mediterranean vibe, too. They look amazing with fascinating branch structure in bloom and out!
One caveat– Chaste trees do self-seed, however the seedlings are unlikely to survive unless they land in very well draining soil.
If you don’t have these conditions ordinary perennials will do the job. Salvia May Night, Coneflower (Echinacea) Fragrant Angel, and Hummingbird Mint (Agastache) Blue Fortune are all excellent butterfly magnets without risk of uncontrollable spread. I can testify, these plants are continuously covered in butterflies when in bloom. According to Mt. Cuba Center’s 2020 echinacea trials, Fragrant Angel was the top performing cultivar for attracting pollinators.
If it’s the conical flower form that you crave, try a French lilac or conical lacecap hydrangea. These won’t necessarily attract that many butterflies, but the flower cones are very pretty in their own right.
By the way, this is one case where a so-called “sterile” butterfly bush cultivar won’t do. Despite the breeding of less prolific hybrids, a study found that most new cultivars are still about 2% fertile. Since a single flower cluster can produce up to 40,000 seeds, these introductions are still too fertile to safely plant. Maybe a sterile one will be bred eventually. Until then, if you decide to remove just one invasive from your property, butterfly bush is a good place to start.
Orange Vols hybrid daylily, not “Ditch lily”
If you’ve ever wanted to buy “wild” orange lilies and couldn’t find them for sale, this is why: they aren’t native at all; they’re Asian imports that escaped cultivation in colonial times and naturalized all over the country. Multitudes of the unflatteringly named “ditch lilies” lining every country road in summer are testament to its invasiveness, especially in the Mid-Atlantic Region where conditions favor it.
Yes they are certainly pretty, but they don’t belong in our wild places. Unfortunately they are so widespread now, we’re not going to stop their spread. But we can avoid making it worse.
If you love orange daylilies (as I do) pick a hybrid that doesn’t spread. A nice one is Orange Vols. Just know that deer love all daylilies, and will relentlessly seek out the buds to eat just as they prepare to open.
Better yet, plant butterflyweed (Asclepias tuberosa) an orange-flowered native that not only attracts butterflies but is a host plant for Monarchs. Deer won’t eat it either. Butterflyweed (not a weed despite the name) also comes in chrome yellow and is very easy to grow.
Two other orange options could be Tiger lily and Fire lily. (Just don’t plant tigers next to true lilies, as the former is a carrier for a disease that could wipe out your hybrids.)
In short, it’s best to avoid “ditch” lilies entirely and stick with the arguably prettier, less prolific hybrids.
So there you have it. If you happen to be growing one or more invasives, whether intentionally or inadvertently, I hope I’ve convinced you that all is not lost. There’s no need to pull them all out immediately!
Take your time, figure out what to get instead, and replace one or two a year. Thankfully there are nice alternatives, and remember– you’re helping to preserve our native treasures when you take out an invasive. That thought alone helps take the sting out of removing an old favorite.
Your list of invasive plants with suggested alternatives is excellent!
See you Tuesday at Dr. Tallamy’s talk!!!
Thanks, Becky!