Oxalis, often recognized as wood sorrel or the shamrock plant, is a popular choice for indoor gardening due to its colorful foliage and delicate blooms. These plants grow from small, underground storage structures, technically corms or rhizomes, though commonly called bulbs. Planting these structures in pots allows for controlled conditions and a vibrant display year after year. This guide focuses on the techniques required to successfully plant and establish these corms in a container setting.
Preparing the Planting Environment
Successful Oxalis growth requires selecting the correct vessel and medium. The container must have drainage holes, as the plants are intolerant of standing water and will quickly succumb to root rot. A pot size of 6 to 8 inches in diameter is appropriate for starting a new batch of corms.
Use a light, well-draining potting mix, ideally one formulated for houseplants. Enhance drainage by amending the mix with materials like perlite or coarse grit, aiming for a slightly acidic to neutral pH (6.0 to 7.0). Avoid heavy garden soil because it compacts easily and retains too much moisture.
Before planting, examine the Oxalis corms, which resemble tiny, segmented pinecones or ridged tubes. Ensure they are firm and free from mold or soft spots. Orient the corm vertically with the narrower, sometimes pointed end facing upward, as identifying the growing point is important.
Step-by-Step Planting Instructions
Begin the planting process by filling your prepared pot about three-quarters full with the well-draining potting mix. Gently press the soil down, ensuring it is level but not heavily compacted, as the corms require aeration to sprout efficiently. Leave an inch or two of headspace at the top of the pot for watering.
The Oxalis corms are typically small and should be planted relatively shallowly to encourage quick emergence. Place the corms onto the surface of the soil, ensuring the narrow or pointed end is oriented upward. If you cannot determine the top, you may lay them horizontally, though this may delay sprouting.
For a dense, full display of foliage, position the corms approximately one to one-and-a-half inches apart across the soil surface. Cover them with one to two inches of the remaining potting mix once they are spaced. Lightly tamp the soil surface to remove any large air pockets and ensure good contact between the corms and the medium.
Initial Care for Successful Sprouting
Immediately after planting, provide a thorough, deep watering to settle the soil around the newly placed corms. Water until you see moisture draining freely from the holes at the bottom of the pot, then discard any excess water collected in the saucer. This initial soak helps to activate the corms and begins the hydration process.
During the sprouting phase, which can take two to four weeks, place the pot in a location that receives bright, indirect light. Direct, intense sunlight can be too harsh at this stage and may cause the soil to dry out too quickly. Maintain a moderate room temperature, ideally between 60°F and 75°F, as these conditions are favorable for initiating growth.
Managing soil moisture before leaves appear is important. Keep the soil lightly and consistently moist, but never waterlogged. Check the soil every few days, watering only when the top layer feels dry to the touch. Consistent moisture prevents the corms from rotting while they develop roots.
Long-Term Maintenance and Dormancy
Once the Oxalis has sprouted and established a full canopy of leaves, its care routine shifts to maintaining active growth. The plant will thrive in a spot that offers bright, indirect light, such as a few feet from a sunny window. Insufficient light will cause the stems to stretch and look “leggy” as they reach for a light source.
Adjust watering to the plant’s active growth rate, typically when the top inch of soil has dried out. Soak the pot thoroughly until water flows from the drainage holes, removing all excess water immediately. During spring and summer, feed the plant monthly using a balanced liquid houseplant fertilizer, such as a 10-10-10 formulation, diluted to half-strength.
Oxalis plants enter a period of dormancy, often triggered by extreme heat, cold, or reduced light in late summer or autumn. Recognize this phase when the foliage looks tired, droopy, or the leaves fail to open fully. As the leaves yellow and die back, gradually reduce and then stop watering and fertilization.
The corms should remain in their pot and be stored in a cool, dark, and dry location, such as a basement or garage, for a rest period lasting one to three months. This dormancy is necessary for the plant’s health, allowing it to recharge its energy reserves for the next growing season. To restart growth, bring the pot back into a bright location, resume light watering, and the plant will begin to sprout new foliage within a few weeks.