Scrambling Fumitory (Fumaria muralis)
Scrambling fumitory is a soft, trailing annual weed that commonly appears in gardens, lawns, and disturbed soil across New Zealand. It germinates mainly in spring and autumn but can grow throughout the year in mild conditions.
It’s not especially competitive with established turf but can quickly spread across bare or patchy lawns. In flower gardens and crops, its climbing, sprawling growth can smother surrounding plants or make harvest difficult by tangling through desirable vegetation.
This weed belongs to the poppy family (Papaveraceae) and was formerly classified under Fumariaceae.
Identification
Scrambling fumitory has delicate, bluish-green foliage made up of many finely divided leaflets. The stems are weak and creeping, often forming a tangled mass over soil, plants, or garden edges.
Seedlings begin with long, narrow cotyledons and the first few leaves usually have three narrow leaflets. Mature plants produce clusters of small tubular flowers, usually pale to deep pink with a purple tip, appearing through most of the growing season.
The plant can look similar to common fumitory (Fumaria officinalis), but that species produces larger flower clusters (typically 20–40 florets per stem, compared with under 15 in scrambling fumitory).
Why It’s a Problem
Scrambling fumitory spreads rapidly through open or disturbed areas, using its long stems to climb over nearby plants. In lawns, it can spread through thin grass, particularly in damp or compacted soil.
In gardens or newly sown turf, it can form dense mats that suppress young grass seedlings. Although it doesn’t root at the nodes, its spreading growth habit and abundant seed production make it a nuisance wherever ground cover is thin.
Management and Prevention
Healthy, dense turf is the best defence against fumitory. It relies on light and space to establish, so maintaining lawn density and soil health will prevent re-infestation.
Cultural control methods:
- Improve turf density: Overseed and fertilise regularly to prevent bare patches.
- Hand removal: Pull or hoe young plants before flowering to stop seed production. The shallow root system makes removal easy when soil is moist.
- Mowing: Frequent mowing in lawns will weaken fumitory and prevent flowering.
- Avoid soil disturbance: It germinates readily in disturbed soil, so minimise cultivation in established lawns.
Chemical Control:
Scrambling fumitory is moderately easy to kill with herbicides when young but becomes harder to control once mature.
Effective options include:
- Mecoprop/ioxynil/bromoxynil mixtures (Image): Effective for selective control in turf when applied early in the growth stage.
- Triclopyr/picloram mixtures (NZLA Gold): Provide strong control of older plants.
- Glyphosate: Suitable for spot-spraying in garden beds or hard surfaces, though it will damage grass.
Avoid relying solely on 2,4-D, MCPA, or dicamba, as fumitory becomes increasingly tolerant to these herbicides as it matures.