Home > Great Big Greenhouse Blog > March 2015 > OXALIS--MORE THAN JUST THE SHAMROCK


Erin go Bragh!  Many folks purchased a “shamrock” plant as a gift or party decoration for St. Patrick’s Day.  Oxalis regnellii makes a sweet year-round houseplant, easy to grow on a bright windowsill.  There are, however, more than 800 other species of oxalis in the world, many of which would make great additions to your garden or houseplant collection.

Generally known as wood sorrels, most have the familiar clover-like three-leaflets with pink, yellow, or white flowers. The genus name oxalis comes from the Greek for sharp or acidic, and the plant does taste sour from the oxalic acid.  Oxalis is considered poisonous to cats and dogs, and while the plants have been used for food and for medicinal purposes in some cultures, it would be wise to keep them away from small children as well.

Many people see oxalis as a weed, and there are varieties that deserve this appellation.  The common yellow wood sorrel (Oxalis dillenii) can be found growing in woodland clearings, along roadsides and railroads, and in lawns, and most of us would likely give it a shot of weed killer.  On the other hand, Oxalis triangularis, “Purple Shamrock”, with its pretty purple leaves and white to pale pink flowers is a popular annual for flowers beds and containers, and it can winter over in a sheltered location.  Two pretty perennial oxalises for our area are Oxalis crassipes ‘Alba’ and O. crassipes ‘Rosea’, with white or pink flowers over green leaves.

Along with the Shamrock and Purple Shamrock, another oxalis that makes a pretty houseplant is the Iron Cross Oxalis (Oxalis deppei or O. tetraphylla) with rosy pink flowers atop “four-leaf clover” leaves with purple cross markings.  Then there is the “Fire Fern” (Oxalis hedysaroides ‘Rubra’) with bright yellow flowers and deep red leaves.

Most oxalises are native to South Africa and South America.  They propagate by bulblets or seed.  Allow soil to dry slightly between waterings.  Keeping the plant too wet may cause the bulbs to rot.  As a houseplant, oxalis should be given a rest period of a few weeks following its flowering period.  Very bright light to some direct sun helps maintain fullness.  If the plant becomes leggy or the leaves get spotty, cut the plant back to the top of the soil, and it will put up fresh new leaves.  You gotta love a plant that fixes itself!  
Posted: 3/20/2015 by Margot | with 0 comment(s)
Filed under: MargotGunn, TheGreatIndoors
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