A Shamrock plant is a member of the Oxalis genus, and part of the wood-sorrel family, Oxalidaceae. It appears in flower shops around St. Patrick’s Day. These plants got the nickname “Shamrock Plant” because their thin, triangular leaflets resemble a lucky clover plant. The name “shamrock” comes from the Irish word seamróg which means “young clover.” There are several stories associated with the Shamrock plant. One of the most popular is that St. Patrick, Ireland’s patron saint and the person credited with bringing Christianity to Ireland, plucked a Shamrock plant from the grass and used it to explain the Holy Trinity to his congregation. The three leaves, he said, represented the father, the son, and the Holy Spirit. St. Patrick’s Day is celebrated on the anniversary of his death. The Shamrock plant is also credited with the arrival of spring and as a symbol for the “season of rebirth.
Shamrock Plant Description
A Shamrock plant is a small, bulb plant approximately 5”-7” tall. The thin leaves are usually divided into three leaflets, though some varieties may have four or more leaflets, and resemble clover. The leaflets exhibit “sleep movements” which means they spread open in the light and close up when it gets dark. When placed in bright, indirect light, Shamrock plants produce delicate, colorful flowers.
Shamrock Plant Varieties
Oxalis regnelli, the green leafed Shamrock plant, produces small, white flowers in late spring and summer.
Oxalis triangularis (Purple Shamrock or False Shamrock) has dark purple, triangular shaped leaves and pinkish/lavender flowers.
Oxalis versicolor (Candy Cane Oxalis) produces white, trumpet shaped flowers with red petal edges in early spring.
Oxalis tetraphylla (Iron Cross Oxalis or Good Luck Plant) has four heart shaped leaflets per leaf. The base of each leaflet is dark purple, making the leaf look like it has a beautiful cross at its center. The plant produces trumpet-shaped, dark pink flowers during the summer and fall.
Oxalis adenophylla (Silver Shamrock) has gray green leaves divided into heart shaped leaflets. It produces white flowers with lilac veins and lilac tips.
S. Regnelli S. Iron Cross S. Candycane
A Shamrock plant is easy to care for and adds a touch of spring to your home. However, these are perennial bulb plants and the leaves start to die back after the flowers fade. Don’t throw the plant out; Shamrock plants just need a little rest before starting to grow again. Follow the detailed instructions in the Resting Period part of the Care Section below and you’ll be able to enjoy your plant for many years. These plants are considered slightly poisonous if eaten in large quantities and should be kept away from pets and children. Read more about common houseplants that can be dangerous in my book Don’t Feed Me to Your Cat: A Guide to Poisonous Houseplants.
Shamrock plants need bright indirect light to grow well and produce flowers. They often bloom all winter if kept in a well-lit spot. The leaves of a Shamrock plant fold up at night and re-open when light returns.
Keep the soil barely moist but never soggy and allow the top 2” of soil to dry out before watering. It’s best to water a shamrock plant from the bottom so the thin fragile stems of the plant don’t get water logged and the soil stays loose.
Feed monthly in the spring and summer when a shamrock plant is actively growing with a balanced fertilizer diluted to 1/2 the recommended strength. Never feed a shamrock plant when it is dormant and the bulbs are resting.
Shamrock plants grow best in cool temperatures between 60°-70°F (15.6°-21.1°C) during the day and 55°-65°F (12.8°-18.3°C) at night.
Shamrock plants do well in basic household humidity.
The shamrock plant variety oxalis regnelli has small, delicate, white flowers. The shamrock variety oxalis triangularis has delicate little lavender flowers.
Shamrock plants attract aphids, whiteflies, and spiders mites. Use the “green solution,” a mixture of ½ mild soapy water, ½ alcohol and a few tablespoons of mineral oil to get rid of the spider mites and aphids. Yellow Sticky Insect cards is the best way to handle whiteflies.
Fungal rust (brownish/orange discoloration on the backs of leaves) and chlorotic ring spot (yellow rings on the tops of leaves) are the two main diseases to watch out for. In both instances, take the plant out of the pot, scrub the pot with a mild bleach mixture, and then wash it well before repotting the plant in fresh soil. Spray the plant with Neem Oil.
Use a loose and sandy soil rather than a rich and organic soil.
Keep shamrock plants in small pots to prevent over- watering.
If your shamrock plant gets thin and leggy, cut the plant back to an inch or two above the soil line and place it in very bright indirect light. Elongated stems occur because the plant is reaching for the light.
The best time to propagate a shamrock plant is in the early spring right after its dormant stage. Shamrock plants are propagated by bulb division. These plants have very small bulbs that are referred to as bulblets. The healthy bulbs are small, white, and puffy.
After a shamrock plant blooms, the leaves turn yellow, droop, and need to be removed; this usually occurs in the late fall. While it looks like the plant is dying, your shamrock plant is really starting its resting or dormant phase. After all of the leaves have died, stop watering and move your plant to a cool, low- light area. Green shamrock plants need to rest for 2-3 months while purple shamrock plants need only about a month. After your plant has rested for the appropriate amount of time, move it back into bright, indirect light and water as usual. Once new growth appears, fertilize with a balanced houseplant food diluted to ½ the recommended strength. Shamrock plants may go dormant several times a year.
Shamrock plants are very popular gifts for St. Patrick’s Day and Easter.
Poisonous Plant Info
Shamrock plants are slightly poisonous if eaten in very large quantities with a #1 toxicity level.
To help a shamrock plant become fuller and bushier, move the plant to a location that gets more light and be sure the temperature stays on the cool side.
The soil your shamrock is planted in may be too rich in organic matter and not sandy enough. Rich soil helps with leaf growth but impairs flower growth. You can also try stressing the plant by letting it dry out a little more before watering it. This often helps it to flower.
The best time to propagate a shamrock plant is right after its dormant stage when you are about to return it to its normal bright location and start watering again. Separate the Shamrock Plant Bulbs and plant them in slightly sandy soil.
Yellow leaves on a shamrock plant indicate over watering. Try allowing the soil of your shamrock plant to dry out more before you water.