The licorice plant (Helichrysum petiolare) is a popular ornamental species grown primarily for its attractive, mounding, and trailing foliage. This woody, tender perennial, native to South Africa, features soft, silvery-gray, felt-like leaves. Outside of warm climates, it is most frequently utilized as an annual accent plant in container arrangements, hanging baskets, or garden borders.
Cultivation Requirements
The dense, silvery foliage develops best in full sun exposure, requiring at least six to eight hours of direct sunlight daily. While the plant tolerates partial shade, insufficient light results in leggier growth and less intense leaf coloration. Superior drainage is the key environmental requirement, as the plant is highly susceptible to root rot in soggy conditions.
The licorice plant thrives in average, well-draining soils and can tolerate poor soil quality, though it benefits from moderate fertility. As a woody perennial, it is winter hardy only in USDA Zones 9 to 11. In colder climates, it is cultivated exclusively as an annual or must be brought indoors before the first frost.
Planting and Starting New Growth
Do not transplant the licorice plant until all danger of frost has passed and the soil has warmed sufficiently. Nursery-purchased plants should be set out at the same time as heat-loving vegetables, like tomatoes. When planting into the ground or a container, dig a hole just as deep as the nursery pot and gently loosen the roots before placing the plant.
The vigorous, spreading habit requires adequate spacing, often needing one to three feet to accommodate its mature spread. While starting from seed is possible, it is a slower method that sometimes results in varied characteristics, especially with hybrid cultivars. Propagating from softwood stem cuttings is the most common and effective technique for starting new plants.
To take a cutting, select a healthy, non-flowering tip four to six inches long, cutting just below a leaf node. Remove the lower leaves and dip the cut end into rooting hormone, which is optional but stimulates root development. Place the cutting into a well-draining, sterile potting medium and keep it in a warm location with bright, indirect light until roots establish, which typically takes three to four weeks.
Ongoing Maintenance
Once established, the licorice plant is considered drought-tolerant, but this does not mean it can be completely neglected, especially when grown in containers. Overwatering is the most common mistake, leading to root rot, so the soil must be allowed to dry out slightly between watering sessions. Check the soil moisture by inserting a finger; if the top one to two inches feel dry to the touch, it is time to water thoroughly.
Container plants require more frequent watering than those in the ground, particularly during the hot summer months. Apply water directly to the soil around the base of the plant, avoiding excessive moisture on the foliage, which can promote fungal diseases. Good air circulation also helps prevent issues like powdery mildew in humid conditions.
The plant has low fertilizer requirements and does not need heavy feeding. Over-fertilizing can be detrimental, causing the plant to grow too quickly and resulting in less dense, less silvery, and more leggy growth. For plants in the ground, a single application of a balanced, slow-release fertilizer in the spring is often sufficient.
Potted plants can benefit from a liquid balanced fertilizer applied sparingly, perhaps once a month during the peak growing season. Licorice plants are generally resistant to many pests due to the dense, fuzzy texture of their leaves, but they can occasionally attract sap-sucking insects like aphids or whiteflies. If a pest problem arises, horticultural soap can be used to manage the infestation.
Shaping and Renewal
Regular trimming is necessary to maintain the dense, mounding form of the licorice plant, especially in containers. This is best achieved through “pinching,” which involves removing the soft, new growth tips from the stems. Pinching encourages the plant to branch out laterally, preventing the stems from becoming long and bare.
If the plant becomes overgrown or looks thin by mid-season, a more aggressive cutback can renew its shape. Using clean shears, stems can be trimmed back hard to promote a flush of new, compact growth. Pruning can be done throughout the growing season to control size and encourage fullness.
In regions outside of its perennial zones, container-grown plants can be overwintered indoors. Before the first frost, bring the plant inside and place it in a cool, bright location, such as a sunny window. During this period of semi-dormancy, significantly reduce watering until new growth resumes in the spring to prevent root rot.