Shamrock plant (Oxalis)

History of the Shamrock

The earliest reference to the shamrock was in the 5th century when St. Patrick used the shamrock to explain the Trinity to the Druids. There is no proof that this really happened, however, the shamrock continued to become a part of Irish legend and history. Today in Ireland, the three-lobed leaf is a symbol of Ireland and is proudly worn as a “good luck” badge on St. Patrick’s day.Lucky Shamrock

The “lucky clover” is not the same as the Shamrock plant sold at the grocery stores around St. Patrick’s day. The word shamrock is derived from Celtic word, “trefoil” (three-leafed), or “little clover”. Trifolium repens is the small white clover that is found in lawns and also used as a green manure cover crop. Irish experts consider this to be the true shamrock. Although, others may argue that the yellow flowered (Trifolium dubium) is the real deal. Both are difficult to grow indoors.

The shamrocks sold in grocery stores belong to a large family of Oxalis with over 800 varieties, native to Chile and South Africa. They grow from small corms or tuberous roots which produce delicate, clover-like leaves that are light sensitive and close on cloudy days and at night (nyctinstic movements). The leaves range from a green to purple with flowers that come in a variety of colors; white, cream, yellow, pink, purple and red.

Oxalis regnelli, sold as the shamrock plant, has white flowers and green foliage.  Another version, O. triangularis has purple leaves with pinkish to white flowers.

Oxalis triangularis


Indoors – keep in a well-lit location (east or west window) away from hot and cold drafts at temperatures of 60-70F during the day and 55-65F at night. They should be kept barely moist at all times and not allowed to stand in water as that will cause root rot. Fertilize every 2 -4 weeks with a houseplant fertilizer. The plant is relatively pest free.

When finished blooming,  the plant may start to die back.  Allow it to go dormant for 1-3 months keeping the corms cool and dry.  After dormancy, repot and or divide (optional). When signs of new growth emerge, begin to water, fertilize and move to a sunny spot.

Oxalis regnelli and O.triangularis are hardy in zone 6-10. Hardier varieties can be grown outdoors as a nice ground cover. Not only does it make a great houseplant, but the unique foliage can add great accent and color to your outdoor container plantings.

Troubleshooting: Tall & lanky plant – needs more light, too warm (temps over 75)

Yellowing plant – watering too much.

May the luck of the Irish be with you!

Happy St. Patty’s!!