Plants with bursting seed pods expel seeds far from the parent plant. The idea is to reduce crowding of seedlings and improve survival chances. The distance that seeds travel varies for different plants. Pods of Euphorbia boetica, for example, have enough force to fling seeds 26 feet . Listen for popping sounds in your garden and be mindful of flying seeds.
Plants disperse seeds in many ways. Fleshy and attractive fruits entice animals and birds to take a bite and spread seeds along their journey. Coconut seeds float, spreading far from the parent plant, while other seeds take flight or hook onto animal fur. Another mechanism for dispersal is bursting pods that hurl seeds away from the parent plant. As seed pods dry, tension between woody fibres increases until the pod breaks along a weak seam and curls, throwing seeds from the pod.
Bluebonnets are members of the legume or bean family and produce seed pods a few weeks after flowering. Like other plants in the legume family, seed pods of bluebonnet pop open and spread seeds in the vicinity. According to Texas AgriLife Research and Extension Center, hard seed coats reduce germination the first few years -- nature's way of ensuring survival of bluebonnets during drought years. Purchased seeds usually must be scarified to increase germination. Given moist soil and full sun, scarified bluebonnet seeds germinate after 10 days. In Texas, bluebonnets announce the arrival of spring, blooming in the beginning of April.
Some plants that dispel seeds by bursting pods are a nuisance in the landscape. For example, creeping woodsorrel (Oxalis corniculata) produces up to 5,000 seeds per plant. Mature pods fling seeds up to 10 feet from the parent plant. Seeds thrive in warm soil temperatures from 15.5 to 26.6 degrees C. Despite its weedy nature, this plant is attractive and produces bright yellow flowers and heart-shaped leaflets.
The invasive scotch broom (Cytisus scoparius) grows 3 to 10 feet tall and produces yellow flowers. After flowering, pods split open and scatter seeds which remain viable for 40 years. Considered a problem plant, scotch broom replaces native vegetation and reduces habitat for wildlife in upland locations or land near wetlands. Western Washington University recommends removing scotch broom by hand before seed pods develop.
- "American Journal of Botany"; Explosive Seed Dispersal in Two Perennial Mediterranean Euphorbia Species; Eduardo Narbona et al.; 2005
- Master Gardeners Santa Clara County; Popping Wisteria Seeds Pods!; Allen Buchinski; 2003
- Penn State University: The Phases of the Plant Life Cycle
- Texas AgriLife Research & Extension Center at Dallas; Fall is the Time to Plant Bluebonnets; Dotty Woodson
- Utah State University Cooperative Extension: Creeping Woodsorrel
- Western Washington University: Problem Plants