There is just something about Shamrocks that gives them an almost magical quality. Maybe it is all the rhymes and superstitions about four-leaf clovers… or maybe the leaves that fold in half each night or when it is cloudy. Or it might be the connection with St. Patrick's Day and all the Leprechauns. Whatever the reason, Shamrocks are fun, beautiful and easy plants for indoors. There are hundreds of types of Oxalis and several of them make very nice indoor blooming plants.

The variety most commonly grown as Shamrocks for St. Patrick's Day is Oxalis acetosella. It is a four-leaf clover with pure white blooms and a compact growth habit. Another wonderful variety for indoors isOxalis deppei with red blooms and quartered leaves that have a dark zone near the center of each leaf. There is a variety that has huge maroon leaves and pink blooms and another with delicate yellow flowers. Most oxalis have 3 or 4 divisions to the leaf, but they can have up to 9 parts. In addition to being called Oxalis, Fourleaf Clovers and Shamrocks, these plants are also known as Wood Sorrels. Although their leaves look similar, they are not related to clover that grows in lawns and hay fields or to the true Irish Shamrocks. Shamrocks and other Oxalis all need a dormant period each year in order to perform their best. This need for a rest seems to cause lots of confusion. Many indoor gardeners have kept their Oxalis actively growing for years without a rest period, but this is very stressful to the plant. To get the most out of an Oxalis, let it grow and bloom until it starts to look tired. At that point, no matter what you do, it just doesn't look good. This will usually be in summer. When this happens, stop all water and fertilizer and store the plant for two to three months where it is cool and dark. After that period of time, you can either bring it back out and start watering it again or repot it. To select a good Oxalis plant, look for one with lots of new growth emerging. It should have a few flower buds just opening and more on the way. While they aren't the type of plant to fill a pot to the edges, quite a few stems should be emerging from a central area. Be sure to read the section later in this information sheet on how to make Oxalis bloom over and over again.

Tips for Growing Healthy Shamrocks
What are the light requirements for Shamrocks? All Oxalis need lots of light to grow and bloom well. This can even be full afternoon sun in winter, but not in the summer. If you are using artificial light, try to provide at least 12 hours each day.
How much water do they need? They need to be just barely damp. Whenever possible, let them dry slightly between waterings.
Do they have any special temperature requirements? Shamrocks and other Oxalis prefer cool temperatures, especially while in bloom. Keep them in a cool room at night (50-65º) and avoid letting them get warmer than 70-75º during the day. Warmer temperatures will encourage them to go dormant earlier.
Do Shamrocks need much humidity? They do fine with average household humidity. Mist occasionally or place them on a humidity tray.
How much fertilizer do they require? During the winter and spring while they are actively growing, feed them once a month with a liquid or water- soluble fertilizer. When blooming stops, reduce fertilizer to every other month until the plant goes dormant.
What type of soil do they prefer? Oxalis should be planted in well-drained peat-based potting soil such as Bachman's Exceloam.
When should I repot my Shamrock? After they have been dormant for two or three months, they can be repotted and divided if needed. As often as not, they are left in the same pot and soil for several years.
Will they need any grooming? Just snip out bloom stems after they have passed their prime. An occasional gentle shower will remove any dust.
How are they propagated? Oxalis can be divided  easily while dormant. Just barely under the surface of the soil there will be small, bulb-like structures that can be gently pulled apart and potted in small groups.
Troubleshooting Problems with Shamrocks
Why aren't my Shamrocks blooming? If the plant has already bloomed in the past year and hasn't had a rest period, it may just be exhausted and need a few months dormancy. If it is young and yet to bloom, it may need more light.
What makes them grow too tall and thin? This is usually a result of not enough light. It can also happen when Oxalis are grown too warm.
If the leaves are yellowing, what is the problem? Yellow leaves usually indicate too much water, especially if the lower, inner leaves are affected.
What causes brown edges on the leaves? They develop brown edges from any kind of leaf shine product or insecticide.
If there are spots on the blooms, what is the cause? This is usually the result of misting while it is too sunny.
What causes them to wilt? If the root system gets too dry, the plant will wilt. Try soaking the roots to see if the plant  revives. Wilt  can be the result of being kept too wet or too cold.
Are Oxalis prone to any insect problems? Occasionally they will have a few problems with aphids or whitefly, but usually they are not bothered by pests.
Do they tend toward any diseases? The only disease problem is root rot if kept too wet.

Recommended Products                          
Exceloam Potting Soil
Excel Gro™ Fertilizer                                            
Quality Containers and Saucers
Artificial Lights for Indoor Gardening                  
Safe and Effective Insecticides
Gardening Books and Information Sheets

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