Family: Asteraceae
The sterile form of Capeweed, Arctotheca calendula ‘Sterile’, is a low-growing, mat-forming perennial groundcover in the Asteraceae family. It produces grey-green rosettes of leaves and yellow daisy-like flowers, and spreads vigorously by above-ground stolons rather than by seed. Because it doesn’t reliably set viable seed in cultivation (hence the “sterile” designation), this cultivar is used in landscape settings for quick vegetative cover and attractive spurts of bright blooms without the same seed-dispersal concerns.
However, while marketed as sterile, this plant still has the capacity to escape into adjacent open or disturbed areas via its creeping runners, and in some regions may behave invasively. Although seed-production is limited by design, the vegetative spread and capacity to form dense mats can suppress native ground-cover and colonize bare soil if not carefully managed. Thus, when used in Hawaiʻi landscapes (or similar settings), care should be taken to contain its spread and monitor for unintended expansion into adjacent natural vegetation.
High Risk Traits:
- Spreads aggressively by stolons and root tubers.
- Forms dense mats that smother other plants.
- Tolerates a wide range of soils and disturbance.
- Documented weed in agriculture and natural areas.
- Resistant to some herbicides.
- Lacks natural predators in new environments.
Low Risk Traits:
- Sterile; produces no viable seeds.
- Not a climbing plant.
- Non-toxic to humans.
- Does not form a persistent seed bank.
