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A Beautiful, But Often Overlooked Desert Bloomer

Oxalis triangularis

Whether in ground or in pots, these under-the-radar plants are perfectly suited to the Arizona climate.

By John Roark | Photography by Matt Pfeilstucker

While more than 500 species of Oxalis are prevalent in Brazil, South Africa and Australia, the tuberous genus has a relatively low profile in the United States—especially in the Southwest, where growing conditions are ideal. Many people’s awareness of the species is limited to the purple-leaved shamrocks found in grocery stores and nurseries around St. Patrick’s Day.

A member of the wood sorrel family, Oxalis is a charmer in pots or as a unique decorative border in Arizona gardens, proffering cloverlike foliage and five-petaled blossoms in a rainbow of colors. 

“Oxalis is not a commonly used plant and thus provides an unusual vibrancy to borders,” says Phoenix Home & Garden Masters of the Southwest award-winning landscape architect Greg Trutza. “I like using it with traditional gardening styles as it invokes a cottage garden aesthetic. It can be used as a mass planting; however, the arrival of summer dormancy necessitates removal of the dried foliage.” 

Phoenix gardener Matt Pfeilstucker, who has nurtured as many as 120 different species in his backyard, raves about the wide variety of foliage and bloom colors and would like for more gardeners to know about the plants. “Oxalis are kind of an underdog around here, and that’s part of the reason I fell in love with them,” he says. “The cool thing is how perfectly they thrive in the Valley. Every fall they start coming back to life once you start watering them.”

Trutza notes that Oxalis are surprisingly tough plants, as they store reserves in their underground rhizomes. He recommends providing a slight mounding of the soil for drainage, and initially placing the bulbs
8 inches apart to quickly provide fullness to a foreground planting.

For more information, see Sources.


SIZE: 8″H by 8″W
BLOOMS: Five-petaled flowers in white, pink, rose, lavender or yellow; variegated varieties are also available
WATER NEEDS: Moderate; allow soil to dry out between watering
SOIL: Well-drained, sandy
LIGHT: Full sun to partial shade

MAINTENANCE: Prune as desired to control size and shape

Oxalis simplex
Oxalis spiralis vulcanicola
Oxalis purpurea, ‘Garnet’
Oxalis nidulans, ‘Pom Pom’
Oxalis obtusa, ‘Orange Dream’
Oxalis obtusa, ‘Pink’


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