How to Care for and Grow the Physalis Plant

The Physalis plant, known by many as the ground cherry, husk tomato, or Cape gooseberry, is a unique addition to a garden. A member of the nightshade family, it is related to the tomato. Its most recognizable feature is the papery, lantern-like husk, called a calyx, that envelops the fruit inside. This husk protects a small, round berry that, depending on the variety, can range from sweet and tangy to purely ornamental.

Understanding Physalis Varieties

Before planting, it is helpful to distinguish between the different types of Physalis, which are categorized as either edible or ornamental. The two most common edible varieties are Physalis pruinosa, or the ground cherry, and Physalis peruviana, known as the Cape gooseberry or goldenberry. Ground cherries are smaller, sweeter, and grow on low, spreading plants, often dropping their fruit to the ground when ripe. Cape gooseberries grow on taller, more upright plants and produce larger, tarter fruits commonly seen in markets.

The primary ornamental variety is Physalis alkekengi, the Chinese lantern. This plant is cultivated for its vibrant orange to red papery husks that are used in dried floral arrangements and autumn decorations. While the fruit of the Chinese lantern is technically edible when fully ripe, it is often described as tasteless and is not the reason for its cultivation.

Planting and Site Selection

Physalis should be planted outdoors after all danger of frost has passed, as they are tender plants. Many gardeners start seeds indoors about six to eight weeks before the last expected frost date to get a head start on the growing season. Sow seeds a quarter-inch deep in a quality seed-starting mix, keeping the soil consistently moist until germination.

Once seedlings have developed at least two sets of true leaves and outdoor temperatures are stable, they can be transplanted into the garden or a container. These plants require a location that receives full sun, meaning at least six hours of direct sunlight per day. The soil should be well-draining to prevent root issues, with a preferred pH between 6.0 and 7.0. When planting in the ground, space plants about two to three feet apart to accommodate their sprawling nature and ensure good air circulation. For container growing, select a pot that is at least 12 inches deep and wide.

Ongoing Plant Care

The plants require regular watering to maintain consistent soil moisture, especially as the fruits are developing. Allow the top inch of soil to dry out between waterings to avoid waterlogged conditions. A layer of mulch can help retain soil moisture and keep the roots cool during hot weather.

Physalis plants are not heavy feeders, and excessive fertilizer can lead to lush foliage with minimal fruit. A light application of a balanced, low-nitrogen fertilizer or compost when transplanting is often sufficient. As the plants grow, their sprawling stems may require support from a stake or a cage, similar to how you might support a tomato plant. This keeps the fruit off the ground and improves air circulation, which can help prevent disease. Most Physalis varieties are grown as annuals, but in USDA hardiness zones 8 or warmer, they may behave as perennials.

Harvesting Physalis

For edible types like ground cherries and Cape gooseberries, the most reliable indicator of ripeness is the husk. The papery calyx will transition from green to a tan, straw-like color and become dry to the touch. The fruit inside will also change to a golden-yellow or orange hue. A very common sign of peak ripeness for ground cherries is that the fruit will fall from the plant to the ground, making harvesting as simple as gathering them from below the plant.

For the ornamental Chinese lantern (Physalis alkekengi), the goal is to harvest the stems for their decorative husks. The best time to cut the stems is when the lanterns have developed their full, vibrant orange-red color but before they begin to fade or deteriorate. You can cut long stems and hang them upside down in a cool, dark place to dry for use in arrangements.

Common Problems and Solutions

Flea beetles are a frequent issue, chewing small “shot-holes” in the leaves, which is mostly a cosmetic concern for mature plants but can harm young seedlings. Floating row covers can protect young plants, and maintaining a clean garden environment helps reduce their populations. Another pest to watch for is the tomato hornworm, a large caterpillar that can be removed by hand.

Fungal spots can appear on leaves, particularly in humid conditions with poor air circulation. Ensuring proper spacing between plants and watering at the base to keep foliage dry can mitigate these issues. Blossom end rot, which appears as a dark spot on the bottom of the fruit, can also occur and is caused by inconsistent watering or a calcium deficiency in the soil. Regular, deep watering and ensuring proper soil health at the time of planting are good preventative measures.