Shepherd's purse

About

Shepherd's purse is a small mustard-family weed from the Mediterranean that is now found all over the country. It is mostly a cool-season nuisance in beds and lawns, but its seeds last for decades.

Also called shepherd's-purse, shepherdspurse

How to identify it

Look for

A flat rosette of leaves that range from smooth-edged to deeply lobed like a dandelion's, often with star-shaped hairs. In spring a stem up to about 20 inches rises with tiny white four-petaled flowers, followed by flat, heart- or triangle-shaped seedpods like little purses.

Look-alikes

The rosette can pass for other mustards or even dandelion, but the flat, heart-shaped pods and the star-shaped leaf hairs set it apart.

Where it grows

Gardens, lawns, nurseries, orchards, roadsides and other disturbed spots, often in cool, moist weather.

When

Sprouts in fall and overwinters as a rosette, or sprouts in early spring; spring plants can flower in under four weeks. In mild coastal areas it grows year-round.

How it spreads

Seed only: about 3,000 seeds on an average plant and up to 60,000 on big ones, living up to 35 years in undisturbed soil.

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. Clean up in fall and early spring Prevent

   Remove rosettes in fall or early spring before they bolt; spring plants can flower in under a month.

2. Pull or hoe rosettes By hand

   Rosettes pull easily from moist soil. Seedlings come from the top half inch, so shallow hoeing works well.

3. Organic mulch Barrier

   Mulch over bare soil keeps the tiny surface seeds from sprouting.

4. Burn down seedlings with a contact spray Organic spray

   Horticultural vinegar (acetic acid), fatty-acid soap, pelargonic acid or clove-oil sprays burn what they touch within hours. They work best on young rosettes in warm, sunny weather, and you will need to repeat, because they don't move into roots and bigger plants regrow.

   They kill any plant they touch, so shield crops. Strong vinegar can burn skin and eyes; wear goggles and gloves and follow the label.

5. Fall pre-emergent or broadleaf spray Conventional spray

   In landscape beds, a pre-emergent applied in late summer to early fall stops winter annuals; in lawns, a broadleaf herbicide such as 2,4-D on young rosettes.

   Read and follow the label. Many lawn weed killers also kill or damage vegetables and flowers, so keep spray and drift off garden plants.

Uses, wildlife and pets

Pets

Not listed by the ASPCA. Its leaves and seeds contain glucosinolates that can irritate the gut if eaten in quantity (UC IPM).