Lucky shamrock or common clover?

Around this time of year, we often see shamrock plants popping up in greenhouses and floral shops. But isn't a shamrock just another clover? The term "shamrock" came from the Irish word, "seamrog," which means "young clover." While plants with three leaflets, or trifoliate leaves, can be called clover, plants in the genera Trifolium and Oxalis are most frequently called shamrocks. Species in the genus Trifolium include cover crops like red clover and the common lawn weed, white clover. The shamrock that is commonly grown indoors and is popular around St. Patrick's Day belongs to the genus Oxalis. Oxalis is a tender perennial that grows from small tubers that look like tiny pinecones. They grow best crowded in a pot since they do not have extensive root systems. The roots like to stay close to the soil surface, so they should not be planted too deeply. The plant produces dainty flowers, typically in shades of pink, lavender, yellow or white. Because they are native to warm climates, they are not hardy here in the Midwest and therefore if planted outside must be brought inside in the winter, or just kept inside and treated as a houseplant year-round. When outside, they prefer part shade and well- drained soil that is kept moist but not wet. They will wilt if the soil dries out. If keeping the plant indoors, it prefers a bright window, but not in direct sunlight. They prefer cooler temperatures at night. An interesting fact about Oxalis is a phenomenon called nyctinasty, a rhythmic movement in response to light which causes the leaflets to fold up at night or on overcast days. Oxalis is a relatively low maintenance plant, but don't be alarmed if it starts to decline after a few months. This dormancy period is normal and usually occurs during the summer. When this happens, allow the leaves to dry out and turn brown, then remove the dead leaves and place the pot in a cool, dark spot for two to three months (purple leaf types only require about a month of dormancy) and reduce watering. When the plant begins to show new growth, begin watering again and bring it out into the light. Some of the more popular varieties found this time of year include Oxalis tetraphylla, also called the "Iron Cross" or "Lucky Clover" because it has four leaves, Oxalis triangularis, which has purple foliage and pink blooms, and Oxalis vulcanicola, with purplish-black foliage and yellow booms. Clovers with three leaves generally outnumber those with four by about 100 to 1, hence the belief that a four-leaf clover is lucky. Keep in mind, however, that Oxalis can be poisonous to pets.