The String of needles (Ceropegia linearis) is a semi-succulent climber native to South Africa where it is endemic. It shouldn’t be confused with its cousin, the String of hearts (C. linearis subsp. woodii). It’s an epiphytic plant that grows on trees, but also on rocks and has the reputation of being an easy-to-grow houseplant.
Scientific name: Ceropegia linearis
Growing season: It grows and flowers in summer and autumn.
Temperature: It grows best at temperatures between 70 and 85 F (22 and 29 °C) in summer and is not frost resistant. It prefers winter temperatures of at least 60 F (15 °C).
Hardiness zone: USDA 11a-11b
Average height and width at maturity: It grows up to 6 feet high and 2 feet wide. It takes 4–6 years from planting to reach this size. The growth is about 6 to 8 inches per year.
Dormancy period: Shorter days, cold nights and dry soil cause the plant to go dormant. These conditions are generally met in winter.
Toxicity: No toxic effects have been reported and the plant is considered safe for domestic animals as well as for humans.
This plant has smooth, light purple thread-like stems that grow in clumps from its tuberous roots. Its leaves, up to 2 inches long and 1/4 inch wide, are fleshy but slender and needle-like, earning it the name “String of Needles”. It blooms in late summer or early fall. Its brown-magenta flowers are 3 cm long and its bloom can last approximately 6 weeks. It produces viable seeds.
The plant prefers indirect light, but direct morning sun is very beneficial to its health, especially in winter and fall. Insufficient light leads to poor plant growth and can cause root rot. If the plant does not have enough light, its photosynthesis process is slowed down and the plant uses less water for its cellular activity. For this reason, water sparingly in winter. Otherwise, water only when the soil is dry and avoid getting water on the leaves to prevent rotting. You can dip the bottom quarter of the pot in a saucer of water to allow the substrate to soak without wetting the leaves. This plant needs fertilizer for optimal growth. Feed it with an all-purpose fertilizer every month during the growing season.
You can propagate String of Needles from seed cuttings, but stem cuttings establish more readily and are preferable. Follow the procedure for propagating succulents by cuttings. Rarely does the plant grow so large that it requires extensive pruning, but it may be necessary to remove dead leaves. Use a sterile tool to avoid infection.
Repot this succulent only when it outgrows its pot. Pests such as mealy bugs and aphids can be a problem, but you can keep them at bay by keeping the plant healthy. Use insecticidal soap to eliminate these pests.