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Weeds: Fringed spider flower
Fringed spider flower (Cleome rutidosperma)
Fringed spider flower is a major threat to tropical annual crops – especially peanuts, melons and vegetables. It invades areas where the soil has been disturbed or prepared for planting, smothering young crop seedlings and native plants. Several small infestations were discovered in Darwin in 2000. A major eradication program is underway to ensure that it doesn’t spread to other areas of northern Australia.
Keep a Top Watch
If you notice new or unfamiliar weeds on your land, contact your Quarantine officer immediately. Infestations of fringed spider flower can develop rapidly, so it is vital to identify them early. If you are unsure about the identity of a plant, Quarantine staff can assist.
Profile: Fringed spider flower scrambles over the ground, forming dense mats in sunny places and becoming more upright in shady sites. Dense infestations can stunt or smother young crops by shading and robbing moisture and nutrients from the soil.
Identification: The weed is a soft-stemmed annual species growing to 1m tall. Stems are angular and each leaf has three leaflets. The small mauve flowers have four upright petals. Numerous tiny kidney-shaped brown seeds develop in a narrow capsule. Seeds are ejected a short distance when the capsule splits. Ants also carry the seeds.
Photos below: The Fringed spider flower has small mauve flowers with four upright petals, and each leaf has three leaflets. The weed is a soft-stemmed annual with mauve flowers. It forms dense mats.
Distribution: The plant is native in tropical Africa but has spread widely and become a pest in Central America, Thailand, Malaysia, the Philippines, Indonesia and Christmas Island. It threatens areas of northern Australia with a similar climate.
Threat: The seeds can be transported long distances as contaminants of soil and machinery. If fringed spider flower takes hold in northern Australia, commercial crops, home vegetable gardens and the natural landscape would suffer.
Quarantine: AQIS officers are looking for Fringed spider flower and have assisted the eradication effort in Darwin. Strict quarantine border controls help to ensure that seeds and plant material don’t enter Australia.