Overview
False London-rocket is an upright annual or winter-annual in the mustard family, growing 1-4 feet (30-120 cm) tall and 6-18 inches (15-45 cm) wide on a branched, often bristly-haired stem. The lower leaves are deeply lobed, with a large arrow-shaped end lobe and several smaller side lobes, while the upper leaves are smaller and narrower. From late spring through summer the branch tips carry clusters of small, bright yellow four-petaled flowers about 0.3 inch (8 mm) across, opening a few at a time as the flowering stem lengthens. These are followed by slender, upright seed pods 0.6-1.6 inches (1.5-4 cm) long held close to the stem on short stalks. Sisymbrium loeselii grows fast from seed, completes its cycle in one season, and self-sows heavily, spreading along roadsides, fields, and waste ground. It is treated as a weed across much of its naturalized range and can crowd disturbed soil quickly. The plant gives a long run of yellow bloom but little structure, and it dies once seed has set.
Native Range
Native to eastern Europe and western and central Asia. Sisymbrium loeselii has naturalized widely in North America, especially the western and central United States and Canada, growing on roadsides, fields, rangeland, and disturbed ground.Suggested Uses
Rarely grown by choice, it appears mainly as a volunteer in disturbed and waste ground and is sometimes part of early-successional cover on bare soil. Its young leaves are edible and have been used as a pungent salad green. In managed settings it is treated as a weed rather than a planted ornamental.How to Identify
Appearance
Size & Dimensions
Height1' - 4'
Width/Spread6" - 1'6"
Bloom Information
Blooms from late spring through summer, often May to August, with new flowers opening at the tips as the stems lengthen. The small yellow flowers draw bees and other small insects. Seed pods form below the flowers and ripen and shed quickly, feeding heavy self-seeding.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established
Care & Maintenance
Care Guide
Grows in full sun in average to poor, well-drained soil with a pH from 6.0 to 8.0, and tolerates dry, disturbed ground. Seed germinates in autumn or spring and seedlings overwinter as a rosette before bolting. The plant tolerates heat and drought and needs no feeding or care, which is part of why it spreads as a weed. It self-sows in large numbers, so removing plants before the pods ripen limits the next year's stand. As an annual it dies after setting seed and does not persist as a clump. It is rarely planted on purpose and usually arrives on its own in open ground.Pruning
No pruning is needed for this short-lived annual. Plants are pulled or cut before the seed pods ripen to curb the heavy self-seeding. Spent stems are cleared once the season ends.✓ Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
direct sow
Direct Sow Timing
autumn or spring
Plant Spacing
12 inches