Weeds with seeds like shepherd’s purse

Shepherd’s-purse ( Capsella bursa-pastoris )

Shepherd’s-purse is a winter annual broadleaf weed, but may grow all year in cool coastal areas of California. It is common throughout California to about 7600 feet (2300 m). It inhabits agricultural land and other disturbed areas. Its fruit has a peppery flavor and is sometimes added as a spice to salad greens. However, shepherd’s-purse seeds and leaves contain compounds called glucosinolates, which cause digestive irritation when consumed in quantity.

Habitat

Agronomic and vegetable crop fields, orchards, vineyards, nurseries, gardens, turf, landscaped areas, roadsides, and other disturbed places.

Seedling

Cotyledons (seed leaves) are narrowly football shaped with a rounded tip, pale green, about 1/12 to 1/5 of an inch (2–5 mm) long, with tiny granules on the surface. The first and next few leaves are narrowly football shaped to egg shaped, with rounded tips, and smooth to toothed edges. Later leaves are typically toothed to deeply lobed. True leaves are covered with star-shaped hairs that distinguish shepherd’s-purse from most other weed seedlings.

Young plant

Until the flower stem develops at maturity, plants exist as flat basal rosettes.

Mature plant

Plants grow to about 20 inches (50 cm) tall. Leaves vary in shape and are lightly covered with both simple and forked hairs. Rosette leaves are about 1-1/5 to 4 inches (3–10 cm) long and their edges range from nearly smooth to deeply lobed. Flower stems are single or branched. Stem leaves are sparse, reduced in size, and stalkless. Leaves have toothed or lobed edges, lobed bases clasping the stem, and are alternate to one another.

Flowers

Flowering takes place mostly in late winter or spring, but can take place year-round under favorable conditions. Flower stalks grow erect or slightly horizontal and are mostly 2/5 to 3/5 of an inch (10–15 mm) long. The four white flower petals are sometimes tinged pale pink, and narrow toward the base (clawed).

Fruits

Fruits consist of flat, heart or triangular-shaped pods making this species easy to recognize when mature and distinguishes it from other plants in the mustard family. Each pod has two chambers divided by a narrow ridge (septum). The pods attach to the stem on long stalks. They are peppery in taste, and eventually open to release many seeds from each chamber.

Seeds

Seeds are oblong, slightly flattened, a dull, reddish to yellowish brown, and tiny—about 1/25 of an inch (1 mm) long.

Shepherd’s Purse

Shepherd’s purse (Capsella bursa-pastoris) is a weedy mustard that is normally a winter or summer annual in New York, germinating in the fall and overwintering or germinating in the spring. It is a common weed of winter crops, disturbed soils, hay fields, and waste areas. This species is named for its distinctive, triangular seedpods. It is also the only weedy mustard in New York with star-shaped hairs, which makes it relatively easy to identify even before seeds develop.

Shepherd’s purse infestation

Photo by Robert Videki via Bigwood.org

Shepherd’s purse is one of 3000+ species in the mustard family . For help identifying weedy mustards either in the rosette or flowering phase, please visit our mustard identification page.

Identification

Seedlings: Cotyledons are egg-shaped to rounded with a light green to purple seedling stem (hypocotyl). The first two to four leaves are rounded with untoothed or slightly toothed margins. The first two leaves are opposite, with both unbranched and star-shaped hairs. Subsequent leaves are alternately arranged in a basal rosette. Rosette leaves range from entire to toothed to deeply lobed, mostly deeply lobed, with a line of hairs on the lower leaf along the main vein and upper leaves that are smooth to lightly haired with star-shaped hairs.

Shepherd’s purse seedling

Photo by Joseph M. DiTomasoof University of California-Davis, via Bugwood.org

Leaves: Mature leaves are alternate and may be smooth or hairy and toothed or lobed. Basal rosette leaves are oblong and taper to the base.

Mature shepherd’s purse leaves

Photo by Bruce Ackley of The Ohio State University, Bugwood.org

Shepherds purse star hairs.

Photo by Lynn Sosnoskie of Cornell University.

Mature plant: Stems of the mature plant are slender and green to purple, with gray star-shaped hairs near the base and smoother towards the top, and leaves only on the lower part of the stem. The flowering stem can grow up to .7m (~30″) tall, and sometimes branch towards the top. Stem leaves are alternate and lance-shaped without lobing or petioles (leaf-stems). Flowers emerge in the spring, and flowering is continuous until early summer; if a plant over-summers or emerges in the fall, there can be a round of flowers in the slate fall. The root system has a thin, branched taproot with fibrous secondary roots.

Multiple mature shepherd’s purse plants

Photo by Lynn Sosnoskie of University of Georgia, Bugwood.org

Full mature shepherd’s purse plant with flowers

Photo by Doug Doohan of Ohio State University/OARDC, Bugwood.org

Flowers/Fruit: Each shepherd’s purse flower is relatively small and produced in a cluster that elongates to a long spike, with seedpods forming towards the bottom while new flowers are produced at the top. The flower has 4 white petals (2-4 mm (1/10”-1/5”) long) and 4 green sepals. S hepherd’s purse fruit have a characteristic flattened, triangular to heart-shaped pod reminiscent of an ancient Greek shepherd’s bag, hence the plant name. The fruit is 4-8 mm (3/10”) long and about as wide.

Shepherd’s purse flowers

Photo by Mary Ellen Harte via Bugwood.org

Shepherd’s purse fruit

Photo by Chris Evans of University of Illinois via Bugwood.org

Management

Chemical control

New York specific guidance can be found in the Cornell Crop and Pest Management Guides, or click below for chemical control options for shepherd’s purse from Cornell’s turfgrass and weed weed identification app.

While no herbicide resistant shepherd’s-purse has found in New York, this species has developed Group 2 (AlS inhibitors like imazapyr) resistance in five countries including Canada, and Group 5 (photosystem II inhibitors like simazine and metribuzin) resistance in Europe and in Oregon.

Non-chemical control

Shepherd’s purse seedlings are very small, and control at that life stage is very effective. Tine-weeding and mechanical cultivation can work well in this stage. Rotating with warm season crops and planting competitive crops in high density can also help, as well as field cleanup after shoulder season short crops such as lettuce. Fall harrowing can work well on fall-germinating shepherd’s purse. Dense planting and organic mulches are also very effective, given how small the plant is in early life stages. A nimal grazing provides fair control of the weed.

References

Uva R H, Neal J C, DiTomaso J M. 1997. Weeds of the Northeast. Book published by Cornell University, Ithaca NY. The go-to for weed ID in the Northeast; look for a new edition sometime in 2019.

Cornell University’s Turfgrass and Landscape Weed ID app. Identification and control options for weeds common to turf, agriculture, and gardens in New York; uses a very simple decision tree to identify your weed.

Most organic management suggestions are from Dr. Charles Mohler of Cornell University. Look for an upcoming book from Dr. Mohler on ecological management of weeds, from Cornell University Press.

Treatment Options page from Weed Control in Natural Areas in the Western United States from University of California, Davis. Provides simplified descriptions of non-chemical and chemical weed management options.

The International Herbicide-Resistant Weed Database, found at weedscience.org, provides documentation of global herbicide resistance.