Welcome to the weed atlas!
The Weed Atlas compiled here is hardly complete and subject to review and update. I'm including those weeds that I find here in New York City -in yards, in the cracks of sidewalks, in parks, on piers. NYC enjoys most of the weeds common to eastern North America, so that if you find yourself here and the weed you are trying to identify is in, say Clearfield, PA or Springfield, MA, the atlas may still be of use to you.
Many of us get online now when we want to identify something, and that is no less true for the weeds in our yards. For years I depended on the book Northwest Weeds as my weed ID source because no proper book had been published for the Northeast. Today, that is no longer the case, so that some of what I publish here has been cross-referenced with the excellent Weeds of the Northeast by Uva, Neal, and DiTomaso.
Deciding what is a weed and what is not is a fool's errand. But for the sake of limits, I define weeds to be those plants that grow of their own accord in areas disturbed by the activities of humankind, and are, by my definition, regionally and often globally, ubiquitous. Some weeds can also be distinguished as invasive, although not always alien, to a region. Weeds go wherever we do.
The atlas follows in alphabetical order, with the botanical name first when I can accurately state it. All listings have at least one photo, which can often be clicked on for a larger image to help in identification. Some of the plants listed are noted as edible, but please don't eat anything unless you have positively identified and properly prepared it.
WEEDS OF NYC
Achillea millefolium, Common Yarrow, Milfoil, or Field Yarrow
Common Yarrow is a perennial plant often associated with old cultivated fields and sometimes lawns. If it is mowed, it can form mats of fine foliage close to the ground. Of course, field yarrow is related to the garden Yarrow, but its flowers are generally white, sometimes with a pinkish tinge, and its foliage is very finely cut. Garden Yarrow has been bred to have many colors and in some varieties, soft gray foliage. I grow both kinds in my garden, but beware, the field Yarrow spreads rampantly.
Ailanthus altissima, Tree of Heaven
Young tree, often found growing on fencelines and in pavement cracks.
Ailanthus will grow almost anywhere, roofs, windowsills, cracks in pavement. It has an extremely aggressive nature and is incredibly resistant to permanent removal. I once removed a concrete pad from a backyard in Brooklyn. Underneath this old concrete, hundreds of little ailanthus roots just waiting for the right opportunity. Can be taken out, but requires perseverance. Often confused with Sumac. Ailanthus will get much taller than sumac, in fact Ailanthus will be a tall tree in short time. The sumac has deep red, upright seed heads, the Ailanthus drooping pale yellow seed clusters.
Alliaria petiolata, Garlic Mustard
I spied thousands of Alliaria petiolata or 'Garlic Mustard' plants and hundreds of Hesperis matronalis or 'Dame's Rocket' from a Metro North train window. I saw several good looking clumps of Garlic Mustard in Cadman Plaza Park this spring, where I pulled some leaves and crumpled them in my hands to catch the faint, slow release of garlic scent they're named for. Garlic Mustard is an edible invasive of woods, hedgerows, and fields -but primarily woodland settings. Known for crowding out spring ephemerals, they are often on forest and park manager lists for eradication.
Dame's rocket -also a mustard.
Amaranthus spp., Pigweed
Amaranth comes in many forms, some weeds, some culitvated for their leaves, roots, seeds or for ornamental uses. There is a woman who comes by late spring into summer pulling the amaranth from the fence line along the sidewalk to eat, I presume. There are several varieties of this plant and are easy to misidentify within the species. All have the telltale inflorescence, although with variations in length, bushiness and color. It is an annual plant that tolerates dry conditions. Pull it up early and don't let it go to seed as the thousands of seeds per plant can last up to thirty years in the soil.
Amaranth gone to seed.
Ambrosia artemisiifolia, Common Ragweed
Ambrosia is a mystery to me, but artemisiifolia refers to the leaf structure which is similar to many Artemesia plants like mugwort found one entry below this one. To some the foliage looks similar to that of French marigold, a plant whose origin is really Mexico despite its name.
The stems of Ragweed are reddish and highly pubescent -meaning that there is hair present.
Artemisia vulgaris, Mugwort
Chrysanthemum. Please don't. The underside of Mugwort's leaves are fuzzy and light gray, and its foliage highly aromatic, where as the chrysanthemum not as much. The leaves become thinner and elongated as the plant matures and its flowers are inconspicuous. Mugwort is perennial and spreads via vigorous rhizomes -so pull, pull, pull or enjoy the greenery. I have noticed one sidewalk garden in Red Hook that seems to have struck a fine balance between their perennials and the mugwort, but this is not the norm.
At flowering, mugwort will take on this appearance -rangy with small lanceolate leaves and flowers.
Mugwort flowers up close.
Asclepias syriaca, Common Milkweed
The leaves have a light gray pubescence on the underside.
Dogbanes, which look very similar if you are not looking closely.
Celastrus orbiculatus, Oriental Bittersweet
In summer the vine is green with small cream-colored spots. In autumn, the vine hardens and darkens.
Late autumn berries, commonly used for wreaths.
Oriental Bittersweet, native to eastern Asia, loves fence rows. I first came across this vine on the stockade type fence around our backyard and you'll probably find it on chain links just like the one above. The berries hang on long and are a favorite of birds, so despite their good looks, if you want it gone, get it before it sets fruit. Just make sure it's not the native variety, American Bittersweet, Celastrus scandens. The decorative possibilities of the vine in late autumn are well known, but selling it live or cut is illegal in some states. No wonder it is 'bittersweet.'
Chenopodium album, Lamb's Quarters, also Pigweed
Mature plant, streetside.
The 'goosefoot' name refers to its leaf shape.
Chenopodium (the name: cheno-goose, podium-foot describes the leaf shape) is commonly known as Lamb's Quarters. Some call it Pigweed, confusing it with the Amaranthus species. The common name may hold water however, it seems taxonomists may be changing the Chenopodiaceae classification to Amaranthaceae. This weed grows everywhere in the city and is a common weed from my childhood yard. Drought, sandy soil, and compacted earth are favorite locations for this plant. It can stay compact and bushy, yet sometimes is open and willowy . Young leaves are eaten in salads or cooked and some make a meal out of the seeds -in this way it is similar to amaranth. I like it for its intense magenta leaves often found half way up the plant.
Mature lamb's quarters with magenta leaves at its base.
Fruit in later summer.
Magenta fruit in autumn.
Cynanchum nigrum, Swallowwort
This one's called Swallowwort, cause it'll swallow anything in its path.
The fascinating flower, not quite black, more dark plum colored.
Commelina communis, Asiatic Dayflower
Commelina species here is the non-native, asiatic variety. There are a few tell-tale traits to divine the two. In NYC, you probably have Commelina communis. It's called Dayflower because the flowers are with us only for a day. Its quite a beauty and I let it be in corners of the garden. It spreads but Dayflower is easy to pull.
Dayflower with a common garden companion, Smartweed.
Draba verna, Whitlow Grass
Erigeron philadelphicus, Common Fleabane
It has a pleasing form until flowering, at which time the leaves begin to yellow and the stems get wily.
Pretty, pinkish-white daisy-type flowers. Is it the bane of fleas? I hope I'll never know.
Fallopia japonica, Japanese Knotweed
Attractive plants make successful weeds.
The heart shaped leaves on young red stems give it away.
Hedera helix, English Ivy
English ivy scrambling up trees and across the ground in Prospect Park.
Hedera helix may not be a weed to many, and I don't always consider it a weed myself. But this plant does escape and does get out of control. I think we may have all seen at least one tree with this plant growing all over it. For the many who have shady spots in front of or behind their homes, this has been the answer to concrete. However, there are many different varieties - so choose one that is attractive and less invasive to woodlands. To remove, simply pull it up. It roots from cuttings of the vine, so remember to pick up the pieces.
Lamium purpureum, Purple Dead Nettle
Lamium amplexicaule, Henbit
Linaria vulgaris, Butter and Eggs
Malva neglecta, Common Mallow
Oxalis stricta, Yellow Wood Sorrel
Phytolacca americana, Pokeweed, Pokeberry or Poke
Phytolacca americana is native to the North American continent. As a kid, I used to let the pokeweed grow tall in our backyard and then harvest the stalk, drying it in the sun for a week. Afterwards, I made spears with the woody, straight stalks. Us kids also made "wine" and dye with the berries. We never drank that wine, fortunately intuiting that this was a bad idea. And of course, it is a bad idea because all of this plant is poisonous. However, it is common to boil the young greens in the American South. You may still be able to buy cans of it down there.
Pokeweed in a can.
Poke berries are loved by many birds. While this plant is perennial, it also propagates via seeds dropping from all those happy birds. Pull to remove from the garden, but leave some in the wild parts for the birds. I find pokeweed to be attractive, but that may be just nostalgia.
Pokeweed leaves, berries and rose-colored stems.
Plantago lanceolata, Ribwort Plantain, Narrowleaf Plantain
Mature flowering plant.
Plantago major, Common Plantain, Broadleaf Plantain
Single plantain with seed stalk.
A patch of plantain.
Plantago major is one of the most common weeds of roadsides, lawns, and pathways. This plant will grow in wet or dry compacted soil, areas little else can. There are native species of this plant in the area, but if it's in your garden it is likely to be this one. Best method for eradication is to pull it after a good soaking rain and keep your soil aerated. Otherwise, you'll just have to live with it.
Polygonum caespitosum, Long-bristled Smartweed, Oriental Lady's Thumb, Smartweed
A good sized patch of Smartweed.
It can be a nice garden plant -for a weed.
Rumex acetosella, Red Sorrel or Sheep Sorrel
Red Sorrel flowers can also be yellow.
Rumex crispus, Curly Dock
Aphids enjoying the succulent stems of Curly Dock.
Silene latifolia (alba), White Campion
Tragopogon dubius, Western Salsify
You might think Western Salsify is a giant dandelion. Common throughout the American West, it is making inroads into the drier parts of the eastern states. Hard to get much more east than Long Island, NY.
Dandelion-like seed head can be up to 6 inches across.
Trifolium repens, White Clover
Trifolium pratense, Red Clover
Trifolium repens is a part of the Pea family of plants, and one of many Trifolium (clover) species including Red Clover and Hop Clover. If you do a web search of the word clover you'll get equal parts how to kill it in your lawn and how to grow it in your lawn. Either way you have it, clover is an introduced species commonly used as forage for livestock and honey production. White Clover is a perennial, spreading over ground and rooting at its stem nodes. Pull it or leave it. It does form patches, though some like it more than grass. Doesn't bother me one bit in a lawn.
Trifolium pratense, Red Clover
Red Clover is much like the white clover, but more upright and typically larger. It is often found in old farm fields and roadsides.
Veronica persica, Persian Speedwell, Birdseye Speedwell.
I found this specimen of Persian Veronica in an athletic field in Red Hook, growing at a bland time of the year, maybe late March. I yanked it up and planted it in a barren spot underneath a rose. Now it cannot be stopped, but is easy to pull should it go too far.