Green and purple oxalis
Green and purple oxalis.
Photo courtesy Netherlands Flower Bulb Information Center

It’s that time of the year when you’ll see “shamrock plants” for sale at garden centers, grocery stores, home accessory shops and elsewhere. Prepared for a myth buster? These plants are not shamrocks. They are oxalis, commonly called sorrel or wood sorrel. The real shamrock is in the clover family.

For St. Patrick’s Day, oxalis usually is sold as green to fit the ‘wearin’ of the green’ motto of the holiday. However, this little plant comes in lots of other colors, including copper, purple and bicolor patterns. The tiny, lily- or bell-shaped flowers are white, pink or yellow.

Popular houseplant

Oxalis has been grown as a houseplant for centuries, and today, this tender plant has found new a home in outdoor containers or in the garden. Some bulb catalogs offer oxalis corms and garden centers may have plants as part of their summer foliage selections. (North America has several native oxalis species, including one considered a weed in the lawn and garden.)

Oxalis purchased around St. Patrick’s Day should be easy to keep as a houseplant until all danger of frost has passed and it can be transplanted outdoors, if desired. Outdoors, oxalis thrives in shady or sunny locations. It’s small enough that it can be used as a tabletop decoration. Or pot it up with other summer annuals to add an interesting texture. Its size also makes it useful as a seasonal edging plant in the ground. Or plant it in clusters or clumps in the ground for an unusual form and texture for the season.

Summer annual

Some oxalis winters over indoors better than others. Some may go dormant or into a resting phase in winter, reviving when spring – and more light – becomes available. Indoors, place oxalis in a bright window. Soil that is evenly moist is preferred, but don’t overwater. This plant falls flat when it needs to be watered.

Charmed Wine
Charmed Wine
Photo courtesy Proven Winners

Consider oxalis a summer annual outdoors. Like most annuals, it will benefit from application of fertilizer, such as Natural Start by GreenView All Purpose Plant Food.

Oxalis sold around St. Patrick’s Day are perfectly fine to grow indoors or out. Here are a couple of varieties to look for in garden centers.

Oxalis Molten Lava
Molten lava oxalis are rich in color.
Photo courtesy Proven Winners

Charmed Wine

Has dark plum-colored shamrock-like leaves the size of your palm. The stalks are celery green. Clusters of blush-pink, lily-shaped flowers emerge among the leaves. Sun scorches this plant, so grow in part to full shade. Fertilizer regularly if grown in a container.

Molten Lava

In low light, the leaves are chartreuse, in sun, they turn a rich orange. This plant is not invasive. The flowers are yellow.

By Jo Ellen Meyers Sharp