Shamrock Plants for St. Patrick’s Day

Shamrock Plants, or Oxalis, appear in plant departments around St. Patrick’s Day. They  have the nickname,  Shamrock Plant, because of their soft, thin, triangular leaves that are divided into three leaflets, just like a lucky clover. Oxalis regnelli, the green leafed version, has small delicate white flowers, while Oxalis triangularis, or False Shamrock, has dark purple leaves and pinkish lavender flowers. Shamrocks are bulb plants and die back after they bloom; but don’t throw them out, they just need a little rest before starting to grow again.

Light: Shamrocks need bright indirect lightVery few houseplants should be placed in direct sun. High light refers only to bright indirect light since direct sun often burns the leaves of indoor houseplants. An area that is too hot and dry encourages Spider Mites and causes blooms to quickly fade. A northern exposure really doesn't provide enough light for high light plants. These plants need to be placed directly in front of an east-facing window, within 1-3 feet of a west-facing window, and within 5 ft. of a south facing window. A high light area has over 300 ft. candles of light. from an east or west-facing window.

Water: Keep the soil of a Shamrock barely moist but never soggy. Allow the top 2” of soil to dry out before watering.  It’s always best to water a Shamrock from the bottom so that the thin fragile stems of the plant don’t get water logged and the soil stays loose.

fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small.: Feed a Shamrock Plant monthly in the spring and summer when it is actively growing, use a basic houseplant food at ½ the recommended strength. Never feed a Shamrock Plant when it is dormant and the bulbs are resting.

Temperature: Shamrock Plants like cool temperatures and do best when the temperature is 60-70 degrees during the day and 55-65 degrees at night.

Humidity: Basic house-hold humidity is fine for this plant.

Soil: The best soil for a Shamrock Plant is a loose and sandy variety rather than the rich  organic type.

Flowers: Oxalis regnelli has small delicate white flowers. Oxalis triangularis has delicate little purple flowers.

Pests: Shamrock Plants attract AphidsSee a picture, learn to identify, and read about Aphid houseplant pests in the Glossary of, whitefliesLearn how to identify and treat the plant pest Whiteflies at how to identify and treat, and spiders mites. Use the “ green solutionIf you don't want to use a commercial chemical product to treat plant pest problems try the “Green Solution.” This is a mixture of water, alcohol, biodegradable liquid soap, and mineral oil. Always test any spray on one or two leaves to be sure it won’t damage the plant. Depending upon how severe the infestation is, you can use these ingredients in varying proportions. If there are only a few pests, dip a Q-tip in alcohol and gently swab them off. For a more widespread problem, start by using a spray of warm water mixed with a few tablespoons of biodegradable soap. If that doesn’t cure the problem, make a solution using 8oz. water & 8oz. alcohol, add two tablespoons of biodegradable soap and two tablespoons of mineral oil. Spray all areas of the plant. Use this solution on leathery leafed plants (except palms), never on fuzzy leafed plants like African Violets or Begonias. For palms, omit the alcohol from the Green Solution. Never spray a plant that’s sitting in the sun or one with very dry soil.    ,” a mixture of ½ mild soapy water, ½ alcohol and a few tablespoons of mineral oil to get rid of the spider mites and AphidsSee a picture, learn to identify, and read about Aphid houseplant pests in the Glossary of Yellow Sticky Insect Cards are the best way to catch the whitefliesLearn how to identify and treat the plant pest Whiteflies at how to identify and treat.

propagationLearn how to propagate plants by plant division at Shamrocks are propagated by bulb division.  With a Shamrock Plant, they are called bulblets because they are very small, white, and puffy.

Toxicity: Shamrocks have a mild toxicity if eaten in very large quantities.


shamrock (c) Stevies dreamstime_4123008