When to Divide an Oxalis Triangularis Bulb

Oxalis triangularis, also called purple shamrock, is commonly sold as a holiday houseplant for St. Patrick's Day. A great way to propagate your purple shamrock is by bulb division. For most bulbs, the best time to divide bulblets is in the fall, but this varies with houseplants, including purple shamrock. Learn when to divide your shamrock to produce more plants.

Leaves of purple shamrock are composed of three leaflets and resemble clovers. The name triangularis refers to the triangle shapes on the leaves that are shaded in purple. Petite, lavender flowers contrast with the purplish, wine-colored leaves. Purple shamrock is native to tropical Brazil and grows in moist areas at high elevations. Sensitivity to cold temperatures limits its landscape use, but purple shamrock is a common houseplant.

As a houseplant, the purple shamrock goes through dormancy up to three times a year. Dormancy is a process in which the plant shuts down and "sleeps" for a period of time. Purple shamrocks remain dormant for about three months. Signs of dormancy include leaf drop and lack of vigor. During this time, cut back on water and fertilizer, and tuck your plant into a cool, dark area. New growth indicates the conclusion of dormancy.

Oxalis triangularis reproduce from bulbs. The University of Vermont Extension recommends dividing bulbs toward the end of plant dormancy, indicated by the appearance of new growth. Remove bulbs from their pots and detach the smaller side bulbs. The baby bulbs are ready for planting right away. Replant them just underneath the soil and keep the soil consistently moist.

If your shamrock grows outdoors, protect bulbs from temperatures below 30 degrees Fahrenheit, which equates to cold hardiness zone 9, and store them in a cool place until spring. Purple shamrock appreciates moist soil and full sun, but will also grow in shaded conditions. Ideal growing temperatures are 70 to 75 degrees Fahrenheit during the day and 50 to 65 degrees Fahrenheit at night.