So pretty, but this weed should come with its own scary music intro.
So pretty, but this weed should come with its own scary music intro.

First, let me preface that “weeds” is a bit of a rude word. What differentiates a common weed from a native plant? Only the eye of the beholder. In my garden, I let the asclepias (aka the humble milkweed) grow, because it is the only food source of the Monarch butterfly larva, and I love butterflies. I reserve the moniker of weed for invasive species that don’t play well with others, or are hard to eradicate. But feel free to let the weeds grow if you love them. Apart from the asclepias, I have a soft spot for the common mallow’s pink flowers and the wild violets. All this to say, this is a completely unscientific approach. This weed business is all about how subjectively pretty, how invasive, and how difficult they are to remove.

From best to worst:
– Milkweed, wild campion, clover, wild violets: As I mentioned in my preface, milkweed is the sole food source of the Monarch butterfly larva, so if you want a great butterfly garden, to your butterfly bush, coneflowers or brown-eyed Susans, you must add a few asclepias. Wild campions are a great reminder you need to mow your lawn, and clover is very good at fixing nitrogen into the soil, while lawns are great at consuming it. Sometimes, it’s better to let partnerships happen, rather than fight nature tooth and nail. Wild violets spread if left unchecked, so it’s not a bad idea to remove most of them past blooming season, unless you want a full carpet the following year.
– Dandelions, dock, smartweed: Although not terribly hard to remove at the start of spring, these spread fast and get more difficult to control once they have bloomed, so they should be removed as soon as you see them come out. Docks and dandelions have pretty deep tap roots, so it’s easier to remove them when the soil is wet, and don’t be afraid to dig them out.
– Plantain, pigweed, mugwort, fleabane: You will rue the day you let those bloom and go to seed. They can cover a backyard in one season, developing a thick carpet of weeds without much of a payoff in terms of flowers or interest.
– Bindweed, English ivy: These vines grow fast, are extremely difficult to eradicate, and will smother other plant life in their path. I have come to recognize bindweed from the first lanceolate true leaves, and remove them immediately.  They are incredibly difficult to remove once they’ve wound and twisted themselves into other plants.  Ivy is best removed in two steps: first, cut the trunks just above the roots, and wait for the vines to die (about a week or two), and then remove them dry. Otherwise, each bit of leaf or stalk will seed a new ivy plant in the ground, so you have to be very careful not to leave any live plant material behind.

And now for the absolute worst. I’m not quite sure if I should lead with the toxic, deadly ones, or Japanese knotweed. Oh, who am I kidding? Japanese knotweed wins. Did you know that in the U.K., you need a special permit to discard dirt that may have Japanese knotweed material?

– Pokeweed, wild tobacco, nightshade: All three are quite common in Brooklyn, and all are toxic. Nightshade is the most dangerous because the berries when ripe are a glossy dark purple, and the taste isn’t unpleasant. The Borgias used nightshade to dispatch their enemies, and a few berries can kill a child. They belong to the same family as the potato, tomato, eggplant plants, and the flowers are quite similar.
– Japanese knotweed: A very attractive plant, with glossy pink leaves that turn green as the plant grows, and grows, and grows. Knotweed can reach 7 or 8 feet; their canes are empty, and the outer fibrous skin dries in place if you cut the canes short, making them perfect to build bear traps. They create thick networks of roots underground, and can regrow from any part of the plant. Removing the stalks only solves the problem for a week or so. There is no real magic: To remove them, you need to dig out the whole mess and remove all the roots. Chances are, they are coming over from neighboring yards, so you will need to create barriers underground to prevent them from coming back. I usually prefer to use elbow grease to chemicals, but Japanese knotweed is a perfect candidate for a clever application of RoundUp. The best time to apply is in the fall, as the plants are about to go dormant. Just spray once on each leaf, and let the glyphosate do its work. Don’t spray the stalks, or drown the leaves, or worse, pour it in the earth; it doesn’t work that way. Glyphosate is a systemic herbicide, and needs to be carried by the plants from the leaves to the roots to do its work properly.

There is a quite wonderful guide to local weeds, with pretty pictures in full bloom,”Weeds of New York City” on the blog New York City Garden. While it’s not complete, the pictures are very lovely. May these weeds never grace your garden!

The Dirt is a monthly column that explores gardening in Brooklyn by Brownstoner commenter and Brooklyn garden designer Marie-Helene Attwood of Edible Petals. Each month, she will answer any questions about Brooklyn gardening over the following weekend.

 

 


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