Dear Miss Floribunda,
After reading your latest column, I got soaker hoses, plus we finally got some good rains in Hyattsville. My annuals planted before the drought could not revive, but a lot of weeds have popped up. In the past, I haven’t worried about identifying them but just pulled them out. However, you have written about certain weeds having been upgraded to wildflowers and how many are useful for attracting birds and pollinators to the garden.
I know you and your colleagues sometimes make house calls. I would be very grateful if you would come by and help me decide what to keep and what to pull out. I have a feeling I have to make a decision soon, or I might be stuck with something I don’t want.
Lost in the Weeds on Longfellow Street
Dear Lost in the Weeds,
Thank you for inviting me to your garden, which was a pleasure for me and a very good idea on your part.
I was very sorry to have to tell you that the “wild grape” you like so much, with its lovely mauve berries, is the dreaded porcelain berry (Ampelopsis glandulosa) — an invasive alien species from Asia that can take over your garden like a Purple Horde. It is a good food source for many birds and some insects, but the birds’ habit of eliminating its seeds in our gardens has made it a regional menace. The porcelain berry deprives other plants of sunlight, water and soil nutrients; and its extensive root system with long tap roots is devilishly difficult to dig out.
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If you want to make your garden bird-friendly, there are many noninvasive native shrubs with attractive and beneficial berries, such as American holly, chokeberry, serviceberry, winterberry, viburnums and many others.
I saw another vine in your yard that I did not recognize at all. Fortunately a friend in the Audubon Society, Ariel Birdwell, installed an app on my phone, called iNaturalist, that is easy to use and can identify organisms in seconds. It recognized your vine as Chinese yam (Dioscorea polystachya). This vine escaped cultivation in the 1980s and has become invasive in the southeastern U.S., competing with kudzu as a botanical calamity. More frost-resistant than other yams, it has been able to creep north wherever winter temperatures have warmed above hard freezes. I have not seen it before, but you have it in abundance. Apparently, the yams can be eaten and taste good, so harvesting it might be the best way to contend with it.
You seem to have acquired quite a bit of field bindweed (Convolvulus arvensis L.), which, though native, can be pesky. Its virtue is that its attractive little flowers — very like those of its cousin, the morning glory — produce nectar for bees, butterflies and other small pollinators. On the other hand, it strangles and takes nutrients away from other native plants and grasses, not to mention any other flowers and vegetables you might want to plant. Consider pulling it out.
You also have two native plants favored by many pollinators, but which are toxic to humans and animals: snakeroot (Ageratina altissima) and pokeweed (Phytolacca americana).
Snakeroot is very pretty, with flowers that look like white ageratum; it is a significant source of nectar to native bees, butterflies, flies, wasps and moths in late summer and fall; and its seeds are favored by birds. Snakeroot is a larval host to several important species of moths. However, in the 19th century, cows that grazed on it produced toxic milk that killed quite a few people, including, it is said, Abraham Lincoln’s mother.
Your pokeweed, even if its plump black berries weren’t toxic to almost all animals but birds, would eventually get enormous — up to 20 feet tall — and rob other plants of nutrients.
Most in abundance in your garden is field aster (Symphyotrichum pilosum), which is a pollinator magnet that provides not only food but shelter and breeding sites for many beneficial insects. However, its gangly and rather frowsy habit is a drawback. When in bloom, though, its myriad miniature daisy-like flowers make frothy petticoats around rose bushes and other plants with knobby knees.
The one volunteer plant you have that is not problematic is goldenrod (Solidago) — a keystone species that supports
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over a hundred species of butterflies and moths. Many native bees are goldenrod “specialists,” which are limited to only one or a very few plants as a nectar source. Interestingly, goldenrod’s beauty caused it to be imported to Europe and Asia, where it eventually became declared an invasive species. It had a bad reputation even in the U.S. for a long time because it was blamed for the hay fever caused by ragweed, which blooms at the same time. Now, it is the state flower of Nebraska and Kentucky; Kentucky even has an annual Goldenrod Gala. South Carolina has declared it the state wildflower, and it is the state herb of Delaware.
Native Americans used goldenrod for numerous medicinal purposes, and goldenrod honey and tea are used by herbalists today to promote kidney and urinary tract health, as well as to treat sinus infections and even certain allergies. Goldenrod has also proved to be extremely effective in phytoremediation to stabilize, contain and extract metallic contaminants in soil.
Although you have a lot of work ahead of you, it is a fine thing you’ve undertaken. I wish more people would make the effort to examine what is in their gardens so as to make informed decisions about what to spare and what to eradicate.
Please check the Hyattsville Horticultural Society website, hyattsvillehorticulture.org, for coming events.
