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London Rocket

Sisymbrium irio (sis-SIM-bree-um IR-ee-oh)

Family: Brassicaceae Non-native

London rocket is an annual weed is in the Brassicaceae (mustard) family. It grows up to three feet in height with tall, open stems. Plants have both male and female organs and are pollinated by insects. Its early maturity each spring give it an advantage over desired wildflowers and native plants. In wild lands settings, they can replace native plants. It can reach heights of up to 3 feet tall, however, typically mature to around 20". The leaves can be eaten as a green, however, they are typically eaten when other foods are not available, its spicy-hot flavor being a deterrent. The flowers can be eaten raw, while the seeds are ground into a powder and mixed with other ingredients to make nutrient rich foods that include cereal, baked goods and tortillas. It can quickly recover after being subjected to fire. Its common name, London Rockets, allegedly refers to its rapid regrowth after the Great Fire of London in the 1600s. Small yellow flowers form in clusters at the end of the stems. Its basal leaves may be lobed. In its native habitat, it can be found in desert locations, open fields, roadsides, walls, and other disturbed areas flourishing in the springtime. The summer heat will cause the plant to die. In the US, it is typically found in the southwestern state, and occasionally in numerous other locations. Insects, Diseases, and Other Plant Problems: This weedy plant can harbor insects and diseases that can have a negative effect on other crops in the mustard family. Attempts to eradicate this weed can be very time-consuming. Cutting down or burning before its seeds become viable will exhaust the seed bank, thereby over time, eliminating the plant. It is considered invasive in some areas of the country.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 52 attributes.

How it fits the guild

Optimal soil pH Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Full plant profile

Growing Conditions
Plant type
Annual; Weed
Life cycle
Annual
USDA zones
8a, 8b, 9a, 9b, 10a
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand
Soil pH
Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
Soil drainage
Moist | Occasionally Dry
Available space
12 inches-3 feet
Growth rate
Rapid
Maintenance
High
Form & Appearance
Habit / form
Erect
Leaf color
Green
Leaf type
Compound (Pinnately , Bipinnately, Palmately); Simple
Leaf arrangement
Alternate
Leaf shape
Linear; Oblanceolate; Oblong
Leaf margin
Dentate; Entire; Lobed
Leaf value
Edible
Leaf size
> 6 inches long, 1-3 inches wide
Hairs present
No
Leaf detail
The oblanceolate to oblong basal leaves grow up to 6" long and may be lobed. They have a pronounced midvein. The 4" stem leaves are linear or oblong.
Flower color
Gold/Yellow
Flower value
Edible
Flower form
Raceme
Flower shape
Cup
Flower size
< 1 inch
Flower detail
Small bright to pale yellow flowers form in clusters at the tips of the branches.
Bloom time
Spring
Fruit color
Green
Fruit type
Siliqua
Fruit value
Edible
Fruit size
1-3 inches long, < 1 inch wide
Fruit detail
The fruit is a slender, rounded pod that grows in an ascending pattern on the upper stem. Its length can be 3 times the width. When ripe, it will split open to reveal small red seeds. It will remain green as it ripens.
Stem color
Green
Stem detail
The tall, open, slender stems may be sparsely hairy at its base. The erect stems are mostly branched near the base. The green stems can have a purple tinge.
Wildlife & Ecology
Native status
Non-native
Origin
Europe, Western and Central Asia and North Africa
Distribution
Southwest US and Great Lakes region
Food & Medicine
Edible parts
Fruit; Leaves; Flowers; Seeds
Fruit type
Siliqua

Edibility

The flowers, seed and leaves can be eaten.

Landscape Use
Garden tags
#annual weed #heat intolerant #annual #self-fertile #dry soils tolerant #broadleaf #herbaceous #herbaceous annual #high maintenance #fast growing #weedy
Problems & Resistance
Problems
Weedy
Propagation
Seed

Planted at Hunnicutt

Nobody’s planted this one yet.