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Weeds and Your Garden

One-year Weeds? Or Two? What to do.

The life cycles of weeds differ, and you should tailor your weed-management strategies to fit.

creeping wood sorrel yellow nutsedge
Annual. Creeping woodsorrel or oxalis has shamrock-like foliage. Produces small capsules that can eject seeds a long distance when it matures. Perennial. Yellow nutsedge has triangular stems and leaves. Reproduces by underground tubers that can remain viable for years.

Annuals complete their life cycles in a year and reproduce by seed. Summer annuals, such as redroot pigweed and ragweed, complete their life cycles during the growing season. Winter annuals, such as shepherd’s purse, can overwinter as seedlings and flower the following spring. To decrease these weeds: pull them (it’s okay if some roots stay in the soil); apply a 4-inch mulch; deadhead (cut off flowers before they set seed); and consider using a flame thrower.

Biennials, such as burdock, set seed in their second year of growth, then die. They can be tough to remove. Try deep digging, regular mowing, and heavy mulching.

Perennials, such as Canada goldenrod and ground ivy, live for more than two years. Many reproduce from roots or rhizomes (underground stems), as well as by seed. They can be difficult to control. Repeatedly mow perennials or carefully remove pieces of rhizomes and roots (which can sprout new plants). A "once-over" tillage is not recommended, but repeated tillage, followed by deep mulching, may reduce infestations in your garden.