When you look at a shamrock plant, it may be difficult to believe that such a lovely plant starts out as an odd-looking bulb that looks something like a deformed pine cone. The result is a delightful plant with bright green foliage that will sometimes take on shades or red and purple and sprout tiny white or pale pink blooms. In spite of the delicate appearance of the leaves, the shamrock -- also known as oxalis or wood sorrel -- is a sturdy plant and it is not picky. As long as it has sunlight, it will be happy to look after itself with very little assistance.
Choose a planting site for the shamrock. Although it will grow in partial shade, its colours will be brighter and more flowers will be produced if the plant is located in full sunlight. Good drainage is crucial, so don't plant your shamrock where rainwater pools for more than three hours. You can improve drainage by adding 2 to 3 inches of organic mulch to the soil, such as ground bark chips, compost, peat moss or well-rotted manure.
Dig a hole for each shamrock bulb, and plant them about 2 inches deep and 2 to 3 inches apart. Water the planting area until it is soaked. Shamrocks prefer slightly dry soil, so after planting, water only when the weather is hot and dry. You should see foliage in about 6 weeks, and blooms in 8 to 10 weeks.
Leave the shamrock's foliage in place after the blooms fade, because the green leaves provide nourishment to the bulbs. When the leaves die back and turn yellow later in the fall, it's safe to remove it.
Dig the shamrock bulbs in late autumn. Put them in a cardboard box full of dry sand or sawdust, and store them in a cool, dark place until spring.
In mild climates, oxalis plants can safely overwinter outdoors.