Turnera ulmifolia (yellow alder) is an invasive shrub that was widely introduced as an ornamental plant. In its broad native range of Florida, The West Indies, and Tropical America, yellow alder grows abundantly.
A habitat generalist, yellow alder adapts to a wide range of environmental conditions and soil types. It is invasive throughout the tropical and subtropical world—all the main Hawaiian Islands report naturalization.
Reproductive capabilities are immense due to self-compatibility, year-round flowering, and continuous seed production. Yellow flowers open in the morning, closing by the afternoon. The seeds and flowers are a food source for non-native ants. Ants locally disperse the seeds relatively short distances; dense thickets are common. However, ant dispersal of 20 feet was observed.
*Yellow alder is often confused with Turnera diffusa (Damiana).
Description and Dispersal:
- An herbaceous shrub with woody stems
- Simple leaves, 2 to 4 inches in length, cluster at the stem tops
- Serrated leaf edges
- Solitary flowers grow from the leaf axis
- Yellow flowers have 5 sepals, 5 petals, and 5 stamens
- Fruit is a capsule
- Ant and human dispersed