Shepherd's Purse Identification Guide
How to identify shepherd's purse (Capsella bursa-pastoris) by its distinctive heart-shaped (triangular) seed pods, lobed basal rosette, and tiny four-petaled white flowers.
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Key Identifying Features
Shepherd's purse (Capsella bursa-pastoris) is a common mustard-family annual named for its purse-shaped seed pods. Identify it by:
- Triangular to heart-shaped flat seed pods along the stem (the key feature)
- A basal rosette of deeply lobed, dandelion-like leaves
- Tiny four-petaled white flowers clustered at the stem tip
- A slender, often single, upright flowering stalk
Flowering plants reach 3-18 inches tall.
Leaves & Stems
The plant first forms a basal rosette of leaves that are deeply lobed and toothed, somewhat resembling dandelion or arugula leaves, though variable. Stem leaves are smaller, arrow-shaped, and clasp the stem at their bases. The flowering stem is slender, erect, and sparsely branched, with fine hairs near the base. It has a thin taproot and behaves as a fast-cycling annual that can complete several generations in a year.
Flowers & Fruit
Flowers are very small, white, with four petals in the classic cross-shaped mustard arrangement, clustered at the top of the stalk. As the stem elongates, it leaves behind a trail of the unmistakable flat, triangular to heart-shaped seed pods (silicles), each notched at the top and resembling a tiny purse or shepherd's pouch. These pods are the single most reliable identification feature and persist up and down the stem.
How to Tell It Apart from Look-Alikes
- Field pennycress (Thlaspi arvense): Also a mustard with flat pods, but pennycress pods are round and disc-shaped, not triangular/heart-shaped.
- Wild mustards and rockets: Have elongated narrow seed pods (siliques), not the flat triangular silicle.
- Dandelion / sow thistle rosettes: Lobed leaves look similar, but these produce yellow composite flowers and milky sap, never the white four-petaled flowers or purse pods.
- Bittercress: Has slender straight pods that explode, not flat triangular purses.
The flat, triangular, heart-shaped seed pods instantly separate shepherd's purse from nearly every look-alike.
Where You'll Find It
Shepherd's purse is a cosmopolitan weed of gardens, lawns, sidewalk cracks, fields, roadsides, and disturbed ground worldwide. It tolerates a wide range of soils and cool weather, often flowering very early in spring and again in fall. It is one of the most widespread flowering plants on Earth.
Quick ID Checklist
- Triangular to heart-shaped flat seed pods along the stem
- Basal rosette of deeply lobed leaves
- Arrow-shaped clasping stem leaves
- Tiny four-petaled white flowers at the tip
- Slender upright annual, no milky sap
If you see a slender weed strung with little flat, heart-shaped (purse-like) pods and tiny white flowers, it is shepherd's purse.
Frequently asked questions
What makes shepherd's purse easy to identify?
Its seed pods. The flat, triangular to heart-shaped pods that look like little purses or pouches run up and down the flowering stem and are unlike almost any other common weed, making identification straightforward.
How do I tell shepherd's purse from field pennycress?
Both are mustards with flat pods, but shepherd's purse pods are triangular to heart-shaped, while field pennycress pods are round and disc-shaped with a wide flat margin. The pod shape is the quickest distinguisher.
How many times does shepherd's purse reproduce in a year?
It is a fast-cycling annual that can complete multiple generations in a single growing season, germinating, flowering, and setting seed quickly, which is why it appears almost year-round in mild climates.