Oxalis are grown for their shamrock-shaped foliage and dainty little tubular flowers that fold up on cloudy days and at night. They’re easy to grow indoors or out, making them ideal for borders or rock gardens, containers and hanging baskets outdoors, or as houseplants year round.
The genus Oxalis comprises about 500 species of annuals and perennials, mainly from southern Africa and South America. Their foliage ranges from green to purple, with flowers that come in white, cream, yellow, pink, purple or red. Considered tender perennials in Canada (unless you live in southern mainland B.C.), these members of the Oxalidacae family grow from bulbs, corms or rhizomes, and are both deer resistant and drought tolerant. They’re sometimes called wood sorrels.
How to Care for oxalis
Most oxalis like a cool, sunny or partly shaded location outdoors and grow best in pots, where they’ll flower abundantly and maintain their attractive colour all summer and fall. (Hardy woodland species of Oxalis need moist, fertile, humus-rich soil in full or part shade.) Bring the plants indoors to enjoy throughout winter. Some will go dormant for several weeks in winter; to cut back on watering until the light levels began to increase in the spring.
Water moderately and fertilize monthly while they’re actively growing; keep barely moist when they go dormant. Most varieties grow from six to 12 inches (15 to 30 cm) tall. When started from bulbs, they produce foliage and flowers in eight to 10 weeks.
One of the best container oxalis to try is O. regnelli, because it’s easy to grow and will bloom year-round if placed in a bright window during the winter months. Sold as the shamrock plant, it has white flowers and green foliage.
Other oxalis to try:
- ‘Fanny’: Mauve-pink flowers, apple-green leaves with a lighter green, blotched centre
- O. spuralis subsp. vulcanicola ‘Burgundy’: Deep burgundy-bronze foliage, bright yellow flowers
- O. spiralis subsp. vulcanicola ‘Copper Glow’: Chartreuse foliage tinted with copper, tiny yellow flowers; vigorous spreader
- ‘Sunny’: Deep purple foliage splotched with a lighter purple
- O. triangularis: Pinkish to white flowers, dark magenta-purple leaves with deep rose patterning
- O. t. ‘Birgit’: White flowers, bright green leaves and a dark purple reverse
- O. t. ‘Mijke’: Mauve-pink flowers and burgundy foliage
- O. versicolor: Unusual white flowers trimmed with burgundy-red, linear green leaves; sometimes called Candy Cane oxalis