How to grow the “lucky” Shamrock

Published on Wednesday, 15 March 2017 17:08 - Written by Jim Powell, Smith County Master Gardeners

Friday is Saint Patrick’s Day. We Americans traditionally celebrate with two symbols of this special day - the wearing of the color green and enjoying the beauty of the “lucky clover” Shamrock or Oxalis plant. “Shamrock” is the common name for three different kinds of three-leaf clovers native to Ireland. The Shamrock was chosen Ireland’s favorite emblem because of a popular legend that St. Patrick had used it to illustrate the doctrine of the Holy Trinity.

The common name for Shamrock plants is Oxalis or woods sorrel. The plants should begin appearing in plant departments around St. Patrick’s Day. They have soft, thin, triangular leaves that are divided into three leaflets forming the clover. Two versions of Oxalis are popular in our area. Oxalis crassipes, the green leafed version has small delicate white flowers, and Oxalis triangularis, or False Shamrock, has dark purple leaves with pinkish lavender flowers.

Shamrocks can be grown both as houseplants and outside in the flower garden.

Here are some suggestions for growing Shamrocks if you are lucky enough to receive a plant as a gift for St Patty’s Day, or purchase one for yourself:

Houseplants: As houseplants, they need indirect light, but not the sun because direct sun often burns the tender leaves. The ideal location for the plant is directly in front of an east-facing window, or 1 to 3 feet from a west-facing window. Keep the soil of a Shamrock moist but never soggy. Feed the Shamrock plant monthly in the spring and summer when it is actively growing, using basic houseplant food at half the recommended strength. Never feed a Shamrock plant when it is dormant and the bulbs are resting. At times the plant will look sick and lose its leaves. This dormant (resting) period, which occurs two or three times a year, is part of a growing process common to all plants like Oxalis, which are grown from bulbs. During dormancy, stop watering. Let the leaves die back naturally, then remove brown dead leaves. Generally, plants will “sleep” for about three months. Because of this dormant period, Shamrocks are not suited for growing in groups with other houseplants.

Outdoor Garden: As an outdoor plant, Oxalis crassipes makes handsome mounds of light-green foliage. It often begins blooming in late winter, but flowers more heavily in the spring. Though oxalis has a tendency to invade the lawn, it can be used quite effectively to edge a sidewalk or flower border. It also can be grown in containers or in a rock garden.

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One local gardener wrote, “I love my purple Oxalis. It adds color to my shade garden as well as sunny areas and in pots. When the sun shines through it, it shows the red/purple for a nice surprise. The little pink flowers are a bonus.”

The Oxalis foliage dies back in the summer’s heat. Cut the leaves back severely when this occurs. The plant will reward you in late summer by sprouting, adding new foliage and blooming again. Propagation is obtained by dividing rhizomes, tubers, corms or bulbs (including offsets) at the end of a dormant cycle. Take the bulbs and replant just under the soil’s surface, or in a mix of potting soil and sand. Most Oxalis plants fold up their leaves at night, hugging them tight to the stems until daylight.

Plan to enjoy St. Patrick’s Day festivities Friday while wearing some green. If not, you may get pinched! While you are at it, look for a four-leaf clover for good luck!