JoAnne Skelly: How to grow lucky shamrocks |

JoAnne Skelly: How to grow lucky shamrocks

JoAnne Skelly

St. Patrick's Day is here. The four-leaf clover is a well-known symbol of luck for the Irish and Irish fans everywhere. While the three-leaf shamrock was a sacred plant to the Druids, Saint Patrick taught it represented the Holy Trinity. The original shamrocks were probably white clover, that weedy plant we try to keep out of our lawns. However, now, wood sorrel, Oxalis tetraphylla, has become the shamrock we find available for sale around St. Paddy's Day.

Although wood sorrel goes dormant in the winter when grown outside and may tolerate winter lows to around 15 degrees, it survives outdoors better when cold temperatures stay closer to 30 degrees. It generally is best grown as a house plant here in Northern Nevada. "The varieties most suitable for indoor growing are Irish shamrock (Oxalis acetosella) and good luck plant (Oxalis deppei)" (

A "shamrock" needs bright light and does well in a south-facing window, if it's kept cool with daytime temperatures under 75 degrees and nighttime temperatures between 50 and 65 degrees. If the temperature is too warm, the plant may go into summer dormancy. If you don't have a bright window, place the shamrock under a fluorescent bulb or grow light for at least 12 hours per day.

Soil should be well-drained. A shamrock requires just enough water to keep the soil slightly damp, but never completely dry. While a plant is actively growing, it should be fertilized once a month with a general purpose, water-soluble fertilizer.

Cut off the leaves as they brown and when the leaves completely die back during the summer months, allow the shamrock to go dormant. Then, keep it in a dark, cool room and don't water or fertilize for two to three months, until the new growth appears. Once you see growth, place the plant back in a sunny window and start watering and fertilizing again.

Here are some fun four-leaf clover facts from Better Homes and Gardens:

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There are approximately 10,000 three-leaf clovers for every "lucky" four-leaf clover.

There are no clover plants that naturally produce four leaves, which is why four-leaf clovers are so rare.

The leaves of four-leaf clovers are said to stand for faith, hope, love, and luck.

It's often said Ireland is home to more four-leaf clovers than any other place, giving meaning to the phrase "the luck of the Irish" (

May the luck of the Irish be with you this St. Patrick's Day!

JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at