Lamb's Quarters

A single lamb's quarters plant can produce tens of thousands of long-lived seeds. Harvesting the tops regularly keeps plants from ever maturing, which makes the crop and the control the same job.

Ripe seed heads or stalks shedding onto the ground, and a flush of volunteer seedlings coming up well beyond where the parent plant stood - most obvious in the first weeks of the plant's growing season.

Hoe or hand-pull volunteers while they are small and before they set seed - the existing seed bank will keep germinating for several seasons either way, so this is an ongoing job rather than a single fix. Where the volunteers are themselves edible, harvesting them is the easiest control, but only ever eat or grow on a seedling you can positively identify.

Cut, deadhead or harvest the seed heads before they ripen and shatter, which is far easier than dealing with what they drop. Where the plant is grown deliberately, keep it in defined rows or a contained bed so that volunteers are obvious, and site it only where naturalizing is welcome.

Not a pest but a management issue. This plant sets and sheds seed prolifically, so anything left to ripen builds a persistent seed bank in the soil and returns as a heavy flush of volunteers the following season. Much of that seed stays viable for years, which is why one season of letting it go can take several seasons to undo.

Lamb's quarters itself has no deadly look-alike, but it grows shoulder to shoulder with plants that do, so the positive ID checks matter more here than negative ones.

Positive checks before you pick: diamond or goosefoot-shaped leaves; a WHITE mealy, flour-dusted coating on the undersides and growing tips; no smell at all when a leaf is crushed; no flowers with petals and no berries; and green or pink-striped stems, never smooth red-purple ones. Anything strongly scented, berried, or growing on a thick smooth magenta stem is a different plant.

If you are unsure after picking, throw the whole gathering out rather than sorting it at the sink. If someone has eaten an unidentified green, call poison control or a doctor straight away rather than waiting for symptoms.

Learn the white mealy coating first - it is the one feature none of the look-alikes share - and pick tips one plant at a time rather than grabbing a mixed handful from a weed patch. Watch a patch come up so you know what is in it, and never eat a wild green you cannot name with certainty.

Lamb's quarters volunteers in the same warm, rich, disturbed ground as several plants you must not eat. Black nightshade (Solanum nigrum / S. ptychanthum) is the one to know - it comes up in the same beds at the same time, and its foliage and unripe green berries are toxic, especially to children and pets. Young pokeweed shoots (Phytolacca americana) push up nearby and are strongly emetic and purgative, with dangerous roots. Aromatic goosefoot relatives such as epazote (Dysphania ambrosioides) are a milder issue - toxic in quantity from ascaridole - and are used as a seasoning, never as a pot-herb.