You might have noticed candytuft (Iberis sempervirens) sprawling over a retaining wall in early spring when the plants are covered with pure white flowers.

It's also a standout in rock gardens or alpine gardens, where it easily nestles between rocks, softening the harsh appearance of boulders. With a tidy, mounding habit, it's a good choice for edging a perennial garden or placing along a pathway. Candytuft's glossy green foliage is evergreen in milder climates and semi-evergreen in colder regions.

Plant Facts
Common name: Candytuft
Botanical name: Iberis sempervirens
Plant type: Spreading evergreen subshrub or herbaceous perennial
Height: 12 inches
Zones: 4 to 9
Family: Brassicaceae (Mustard)

Growing conditions

  • Sun: Full sun
  • Soil: Poor to moderately fertile soil with neutral to alkaline pH. Good drainage is important.
  • Moisture: Water when top 3 inches of soil are dry.

Care

  • Mulch: If used as a ground cover, add mulch around plants to deter weeds until they cover the area.
  • Fertilizer: Include a light application of organic fertilizer to the planting hole.
  • Pruning: Shear right after flowering to maintain a neat habit. Fall pruning will eliminate the following year's spring blooms.

Cultivars

  • ‘Purity' (pictured) has white flowers over a long season. Grows 12 inches tall. Zones 5 to 9.
  • ‘Alexander's White' has a compact habit and vigorous flowering in early spring. Grows 10 to 12 inches tall.
  • ‘Autumn Snow' has white flowers in spring and autumn. Grows 12 inches tall. Zones 5 to 9.
  • ‘Little Gem' (‘Weisser Zwerg') has a more compact habit than the species. Flowers in spring and grows 6 to 8 inches tall. Zones 5 to 9.


Garden notes

  • Combine with other rock-garden perennials such as cheddar pink (Dianthus gratianopolitanus) and ‘Autumn Joy' sedum.
  • Use as a ground cover in small spaces.
  • Place this spring-blooming plant in a spot where its white flowers provide a backdrop for emerging, bright-colored bulbs.
  • In colder climates, cover with leaves or evergreen boughs to protect candytuft's evergreen leaves from drying and sun scorch.

Pests and diseases

  • Gray mold and fungal diseases occur occasionally.
  • Snails and slugs may attack.
  • Wet soil causes root rot.


Propagation

  • Sow seeds in a cold frame in the fall.
  • Take cuttings in spring or summer.


All in the family

  • The Brassicaceae family includes more than 3,000 species of herbaceous annuals, perennials, and biennials. Vegetables in this family include cabbage, cauliflower, broccoli, brussels sprouts, kohlrabi, kale, radishes, and horseradish. Perennial and annual plants in this family include rock cress (Arabis spp.), bittercress (Cardamine spp.), and sweet alyssum (Lobularia maritima).


Text by Mary Pestel, photo courtesy of Monrovia Growers; www.monrovia.com