The Shamrock Plant, better known as oxalis, is not actually a shamrock, but a species of wood sorrel. It's leaves are similar in shape to that of the common clover, or shamrock, but the two share no relation. Shamrock plants are sold in florist shops and supermarkets as decorative foliage around St. Patrick's Day and are grown in containers indoors. They are quite easy to maintain, blooming during the winter months and dormant during the summer. They will produce small, white flowers with proper care and will return year after year.
Place the shamrock plant in a bright, sunny east or west-facing window where the temperature does not exceed 75 degrees Fahrenheit during the day, or drop below 50 degrees Fahrenheit during the night. Place a thermometer next to the plant to make sure it always stays in the safe temperature range. The plant will thrive in full sunlight during the winter months.
Water your shamrock plants once per week or as often as necessary to keep the soil moist but not wet. Allow the soil to dry only slightly in between waterings. Water from the bottom by placing the plant's container in a shallow tray of water and allowing it to absorb the moisture it needs. Remove from the tray once the top of the soil feels moist or after about one hour.
Fertilize the shamrock plant once every two to four weeks during the winter months using a balanced houseplant fertilizer. The plant should only be fertilized while it is actively growing. Refer to the manufacturer's instructions for proper dosage and application of the fertilizer.
Remove spent flower stems from the shamrock plant as soon as possible. This will allow the plant to focus on growth of new blooms and conserve its nutrients. Pinch them off with your fingers as close to the base of the plant as possible.
Allow shamrock plants to go dormant during the summer months. Stop watering and fertilizing at the first sign of the leaves dying back, and allow them to dry and turn brown. Remove the dead leaves, and then place the container in a cool, dark place for about three months.
Place the container back into the bright window and begin watering and fertilizing after the rest period is over. New growth emerging from the soil will be the sign that the dormant period is over, and the shamrock plant is in need of water, light and fertilizer.