Iberis, commonly known as Candytuft, is a favored, low-maintenance garden plant. Propagating Iberis allows gardeners to expand their displays, fill new areas, or share these plants. It can also rejuvenate older plants.
Understanding Iberis
Iberis is a genus of flowering plants, cultivated as annuals or perennials depending on species. Perennial varieties, like Iberis sempervirens, are low-growing, evergreen sub-shrubs forming dense mats 6 to 12 inches tall and 12 to 36 inches wide. Annual types, like Iberis umbellata, offer a wider range of flower colors, including white, pink, red, and purple, contrasting with the perennial’s predominantly white flowers.
Iberis produces clusters of tiny, flat blossoms, creating a carpet-like effect from early spring into early summer. Iberis thrives in full sun, tolerates light shade, and prefers well-drained, neutral to alkaline soil. Good drainage prevents crown rot.
Propagation Methods for Iberis
From Seed
Propagating Iberis from seed is a cost-effective way to produce many new plants, especially annual varieties. For perennials, sow seeds indoors 6 to 8 weeks before the last spring frost, or directly outdoors after frost danger. Annual seeds can be sown outdoors in spring or autumn.
For indoor sowing, prepare containers with a well-draining seed-starting mix. Lightly press seeds onto the soil surface, covering with a thin 1/8-inch layer, as Iberis seeds need light to germinate. Maintain consistent moisture and a warm temperature (65-85°F / 18-30°C). Germination occurs within 7 to 20 days, though some perennial varieties may take up to two months.
Cuttings
Cuttings are suitable for perennial Iberis, ensuring new plants are genetically identical to the parent. Take cuttings in late spring or early summer, after flowering and new growth emerges. Select healthy, non-flowering stems 2 to 6 inches long.
Remove leaves from the bottom inch or two to expose nodes. Dipping the cut end in rooting hormone can promote faster root development. Insert cuttings into a well-draining rooting medium like perlite and peat moss, sand, vermiculite, or sterile potting mix. Keep the medium moist but not waterlogged, and place cuttings in a warm, sheltered area with good light, away from direct sun and wind. Roots develop within 4 to 8 weeks.
Division
Division is an effective propagation method for established perennial Iberis, also rejuvenating older clumps. Perform division in spring after blooming, or in early fall. Carefully dig up the mature plant, preserving as much root system as possible.
Gently separate the root ball into sections, each with roots and foliage. For dense clumps, a sharp knife or spade may be needed. Replant divisions immediately into prepared beds or pots at the original depth. Division encourages new growth and enhances plant health.
Post-Propagation Care
Proper care is important for new Iberis plants after propagation. Seedlings or rooted cuttings should be gradually acclimatized to outdoor conditions through hardening off. This involves exposing them to increasing periods of light, temperature, and wind over one to two weeks before final transplanting.
Transplant young plants to their final location in full sun and well-drained soil, spacing them 6 to 12 inches apart for their spreading habit. Water thoroughly after transplanting to settle the soil. Maintain consistent moisture during the first growing season until established, avoiding overwatering to prevent root rot. Protect young plants from extreme weather until their root systems are robust.