ALEXANDRIA, Minn. (03/15/2021) – Around March, shamrocks are sold in grocery stores, discount stores and flower shops as decorations for St. Patrick’s Day. These plants, which have nothing to do with clover, are actually a type of oxalis (also known as wood sorrel). The clover-shaped leaves are available in shades of green, red or purple and can fold up at night or on cloudy days. The five-petalled flowers, carried on long stems, can be white, yellow, pink, or red.
When choosing oxalis plants for a seasonal decoration, choose those with lush, healthy foliage and lots of new flower buds. All oxalis species require cool conditions, especially when in full bloom, and bright light to thrive indoors. A bright, sunny window where the temperature is no higher than 75ºF during the day and 15-25 degrees cooler at night is a good place. Keep the soil barely moist, but not wet. Most species can tolerate a slight drying out between watering. Fertilize monthly when the plants are actively growing. Oxalis have few pests, but aphids or whiteflies can occasionally be a problem.
The plants begin to lose weight after a few months, usually in summer. Let the plants rest instead of throwing the pot away. When the leaves die, stop watering and allow the leaves to dry out and turn brown. Remove the dead leaves and place the container in a cool, dark place for 2-3 months (except for the purple-leaf species which only require about a month of rest).
After this forced rest period, put the container back in the bright window and start watering and fertilizing or repotting again before putting the bulbs back in the sunny window. Place them just below the soil surface in a well-drained, soilless medium. Soon after, new growth should emerge. Oxalis reproduce easily when at rest by dividing the many small onions. The lightbulbs are easy to separate and can be potted in small groups.
For more information on other houseplants, see https://extension.umn.edu/find-plants/houseplants
Until next time, have fun gardening!
May your problems be fewer and your blessings more and nothing but happiness to come through your door!