Of the genus Iberis (pronounced "eye-BEER-us"), there are about 50 species. Iberis refers to Spain and the Iberian peninsula, one area where they are native. Only a few are widely used as ornamentals. Iberis is a member of the Brassicaceae family, which also includes popular vegetables such as broccoli, cabbage, cauliflower, mustard, turnips and such.
Perhaps the most popular species is I. sempervirens (pronounced "semper-VY-renz", meaning "evergreen"). From Spain, its native range extends across the Mediterranean region and into western Asia. In fact, the name "Candytuft" does not refer to its appearance or fragrance, but to Candia (Iraklion) on the island of Crete where it is a common wildflower. Candytuft is not edible, but the roots and seeds possess medicinal properties.
If you garden within USDA climate zones 3 through 9, you may be able to grow it. Candytuft thrives in full sun to partial shade in average garden soil with pH ranging from 6.6 to 8.5. Slightly moist soil is fine, but over-watering must be avoided. In fact, candytuft is drought-tolerant, so it is ideal for gardeners who must restrict their water use.
Mature height is about 12" and spread is about 24". Flowering season ranges from late spring to early summer, depending upon your location. Candytuft spreads by rooting from stems which contact the ground. It's superb as a ground cover in perennial gardens and borders, rock and alpine gardens. Candytuft is very effective on slopes, terraces and cascading over stone walls. Use it beside stepping stone paths, but know that it does not tolerate foot traffic.
Prepare the planting bed for candytuft by cultivating at least 6" deep, removing all traces of weeds. Compacted soil should be cultivated to 10" deep. Composted manure may be incorporated into the soil. Fertilizer may be used. If you choose to do so, incorporate 5-10-15 fertilizer at a rate of no more 2 lbs. per 100 square feet into the top 4" to 6" of soil. Avoid synthetic fertilizers contacting any part of your plants.
Container-grown candytuft can be planted any time you have a shovel handy, but will require monitoring of soil moisture conditions during hot weather to avoid plant stress.
Space plants 12" to 18" apart. Keep in mind that my spacing recommendations are approximate. If you want them to fill in quickly, plant closer together. If you have plenty of time and patience but less money, plant them farther apart. Dig planting holes into the cultivated soil a little less deep than the depth of the growing container. Water the plants thoroughly in their plots. Allow the water to drain a bit, remove the plants from the pots, place them into the holes and back-fill. Press soil around the roots. Do not cover the root balls with soil. The tops should be slightly exposed. Add a top-dressing of mulch around the plants, not on top of them, about 2" to 4" deep. Irrigate thoroughly.
Maintenance is minimal. Candytuft has few pest and disease problems, but they aren't immune. Crown rot is one of the most frequent, and over-watering is the most frequent cause.
Club root is another problem resulting from a combination of conditions: over-moist soil, cool weather and low pH. Again, keeping the soil on the dry side helps. There's nothing you can do about temperature. But you can raise pH, so keeping it above 7.2 is beneficial. If club root becomes a problem, there's no other option than to remove the infected plants and destroy them. Don't compost them. As always, prevention is the best medicine.
Candytuft benefits from pruning soon after flowering is complete. Doing so helps to discourage seed production, maintain compactness and encourage general plant health. Pruning also helps to ensure good bud-set for next year's flowering. You may safely remove up to 1/2 of the top growth.
Plant Candytuft in your garden and imagine walking in spring with fluffy clouds at your feet.
Return to Iberis at goGardenNow.com.