Virginia buttonweed

About

Virginia buttonweed is a native wetland plant that becomes a tough, mat-forming lawn weed in damp Southern yards. Its deep roots and rooting stem pieces make it one of the harder lawn weeds to get rid of.

Also called buttonweed, large buttonweed, poor Joe

How to identify it

Look for

Stems creep low and are often reddish and square. Shiny, dark green, lance-shaped leaves sit in opposite pairs with no leaf stalks. Summer flowers are small white stars with four petals, and by late summer leaves may look mottled yellow-green from a virus.

Where it grows

Poorly drained or overwatered lawns and other wet spots; in the wild, swamps, wet meadows and pond edges.

When

It is a problem from spring through late summer and flowers from about June to November.

How it spreads

By seed, by rhizomes, and by stem pieces that root easily in moist soil after mowing or string trimming.

Most common in

What to do, gentlest first

Start at the top. Weed killers are a last step; always read and follow the label.

1. Dry out wet spots and keep turf dense Prevent

   Water deeply but less often, core aerate, fix drainage, and mow at the right height for your grass. Bag clippings from patches so stem pieces don't spread.

2. Pulling rarely works By hand

   Clemson notes hand pulling is not effective because the deep roots and leftover pieces resprout. If you pull small plants in beds, dig deep and bag everything.

3. Treat in spring while plants are tender Conventional spray

   Clemson lists metsulfuron, or 2,4-D, dicamba and mecoprop (MCPP) products, applied in spring and repeated as the label allows; fall sprays work less well. For large patches with little grass left, glyphosate and then resodding.

   Read and follow the label. Many lawn weed killers also kill garden plants, so keep spray and drift off beds and vegetables. Don't use metsulfuron on tall fescue, on turf under a year old, or under the drip line of trees and shrubs.

Uses, wildlife and pets

For wildlife

Its flowers draw bees (NC State Extension).

Pets

Not listed by the ASPCA.