Common name: Milkwort
Distribution: Native to the Lower Sonoran Zone of Baja California, from about Comondú south to the Cape Region.
Growth Habit: Large upright multi-trunked shrub grows to 15 feet tall. Ovate-lanceolate leaves persist near the terminal ends of each narrow branch. Lower leaves and branches drop off as the plant grows, giving it a pronounced vertical emphasis. Purple sweet pea flowers with a creamy yellow interior appear among the leaves near the ends of branches.
Cultural Requirements: Plants in habitat grow in full sun, along rocky hillsides and canyon walls. Very low water use, although some summer water may encourage a second flush of flowers. Polygala apopetala is reportedly hardy to 20° Fahrenheit, although SDBG never sees temperatures that low so we can’t independently confirm this level of hardiness. Due to the nitrogen-fixing relationship between Rhizobium bacteria and leguminous plants such as Milkwort, these plants require little if any fertilizer.
Features/Uses: Polygala apopetala provides an ideal vertical accent for dry desert themed gardens. At home in undeveloped, rocky soils, these plants require little more than an occasional pruning to favor your desired shape. Plants can be trained into a small tree but naturally grow as a multi-trunked fountain shaped shrub. Profuse sprays of purple and yellow pea flowers contrast wonderfully against the usual blonde and rusty tones of xeric gardens. Milkwort provides a surprisingly green and lush look given the extremes they can tolerate.
Bloom Time: Late Winter and possibly again in summer with some supplemental water.
Where at SDBG: New World Desert Garden
Photos: Rachel Cobb