Guest author Dan Songster submitted this article featuring an outstanding California native plant for May:

• Bladderpod Cleomella arborea (synonyms Peritoma arborea, Cleome isomeris, and Isomeris arborea). 
• Type: Perennial shrub.
• Light: Likes full sun but can take afternoon shade inland.
• Soil: Well drained (but adaptable to clay soils).
• Water: Drought tolerant.
• Common Habitat: Scrub, washes, bluffs, hillsides, and occasionally oak woodlands from the coast to desert edges. 

This fast growing, densely-branching shrub routinely grows in a mounding habit, becoming about 3-6 feet tall and as wide. It produces abundant bright-yellow flower clusters at the ends of its stem branches. These showy flowers are about a half-inch to an inch in diameter, with 4 petals and 6 stamens. Long a part of the Caper Family (Caprifoliacea), it is now assigned to the Spiderflower family (Cleomaceae). The former genus name Isomeris means divided into equal parts, referring to the seed pod. The species name arborea refers to the plant’s somewhat tree-like appearance. 

The flowers are attractive to hummingbirds, bees, and butterflies, and also provide some shelter for various birds and insects. Bladderpod grows well even on south-facing slopes, alkaline soils, and salty conditions. It has been suggested that Bladderpod is a fire retardant plant that will not burn over an open flame.

The flowers stay on the plant most of the year, (one of the few plants in our region that blooms nearly year-round), and is highly fragrant, though opinion is divided on whether the scent is pleasant, unpleasant, or merely interesting.

The distinctive seedpod for which the plant is named is a large, inflated capsule which is edible. It is up to 2 inches long with a swollen, drooping appearance and pointed tip.

Once started, Bladderpod is one of the easiest natives to grow in our Southern California gardens. It can tolerate weekly summer water but can also get by with only natural rainfall. It is easy to grow from seeds, usually growing in a year to 3 feet tall. (It readily self-seeds; once you have a few mature plants in your garden, expect new seedlings to pop up each winter.) 

Note: If the showy but voracious harlequin beetles become a problem, they can be removed by hand or sprayed off with a garden hose. It is usually not possible to eliminate them entirely.