How to Grow and Care for Candytuft

Candytuft (Iberis sempervirens), is technically a woody subshrub, though is sometimes categorized as a perennial. It is evergreen in warmer climates, but more often performs as a ground-hugging, clumping perennial that dies back each winter. Candytuft has small oblong leaves, leathery green, with a low mounding growth habit, and it brightens gardens with abundant white or pink blossoms for several weeks in late spring and early summer. The color of the blossoms stands out nicely against the backdrop of the dark green foliage and also makes these plants a good choice for moon gardens. One thing the flowers do not have going for them is a nice aroma; the scent is actually unpleasant.

Candytuft is best planted from potted nursery starts—in early fall in warmer climates where it is evergreen, in the spring in colder regions where it dies back in the winter. Although it is a slow grower that can take five to 10 years to reach full size, in ideal conditions candytuft is a long-lived plant that will brighten your garden for many years.

Candytuft Care

Candytuft generally grows rather easily in any moist but well-drained soil in a sunny or partially shady location. You will, however, need to prune it regularly to keep it from getting leggy and sparse and to keep it flowering adequately. Potted nursery plants should be planted at the same depth they were growing in their containers, into soil that has been well loosened and amended to improve its drainage. Young plants need weekly watering, but once established, candytuft can get by on rainfall alone in all but the most arid climates.

If you want the plants to serve as ground cover, plant them about 6 inches apart; they will soon fill in to blanket the space.

Light

Candytuft will tolerate some shade but blooms best when planted in the sun. The exception is Zones 8 and 9, where it benefits from some shade in the afternoon during the hottest part of the day.

Soil

Candytuft is native to southern Europe, including areas along the Mediterranean coast; they prefer the kind of gravelly soil found in their land of origin. More importantly, it is critical to provide them with excellent drainage. This perennial prefers to be grown in​ the ground with a soil pH that is on the alkaline side, but it has good tolerance for both slightly acidic and neutral soils.

Water

Once established, candytuft flowers are moderately drought-tolerant, but make sure to water young plants, particularly during dry periods. Well-established plants have no trouble going two or three weeks between waterings, making candytuft a good choice for xeriscaping applications.

Temperature and Humidity

Candytuft is usually considered hardy in USDA zones 3 to 9, though this has different meanings depending on where you live. In warmer zones, this will be a shrubby evergreen plant, while northern gardeners will find it behaving like a typical hardy perennial, dying back to ground level each winter. Zone 3 gardeners will find the plants somewhat borderline; especially cold winters may cause the plants to perish unless they are well mulched for the winter. Between these extremes, candytuft is best described as "semi-evergreen"—not dying back, but prone to losing some foliage and going dormant in the winter.

The natural environment for candytuft tends to have drier air conditions. For that reason, it's not recommended for areas with high humidity such as the southeastern United States, as the flowers tend to wilt and fungal diseases are more likely.

Fertilizer

Fertilizing candytuft is not necessary but can help ensure abundant blooms. A slow-release fertilizer will help candytuft grow if applied in early spring. Choose a low-nitrogen, high-phosphorous mix for best results. For the amount to use, follow the product label instructions.

Types of Candytuft

The name "candytuft" probably conjures images of tufts of candy. However, the name actually originates from the word "Candia," an early name for the island of Crete, which was the source of the first plants imported to Europe. "Tuft" may refer to either the clusters of flowers or the mounded growth habit of the plant. 

The Latin genus name indicates the plant harkens from Spain and the Iberian peninsula (Iberia), while the second part of the name, sempervirens, indicates that the plant has evergreen foliage—the term is derived from the Latin words for "always" and "alive."

Here are a few popular varieties of candytuft:

• 'Purity' has sparkling white flowers and can reach 10 inches in height, with a slightly greater spread.
• 'Nana' is a shorter cultivar that reaches a height of 6 inches and has lovely white blooms.
• 'Autumn Snow' is a well-named cultivar that will rebloom in the fall.
• 'Pink Ice' is a springtime favorite, bearing pink-colored blossoms with dark pink centers.
• 'Alexander's White' is a low-growing form with finely textured foliage.
• 'Little Gem' is a true dwarf form, growing only 6 inches tall.
• 'Purity' is an 8-inch-tall variety that is very wide-spreading.
• 'Snowflake' has unusually large flower clusters, with broader, more leathery leaves.
  

Pruning

To keep candytuft looking tidy, you can prune away the top one-third of the foliage after blooming—this will keep the plant from getting leggy. Some gardeners like to perform this deadheading with a string trimmer after flowering is complete. Without this annual pruning, the plant can become rather scraggly in the border garden.

However, if you are planting candytuft flowers behind a retaining wall, legginess may actually be a good quality. In this case, prune them only if you think the stems are getting too woody-looking. Pruning will spawn new, fresh growth.

Propagating Candytuft

Candytuft is amenable to many propagation methods, but simple root division is the easiest and fastest. Here's how to do it:

1. In fall, just before the plants begin winter dormancy, use a shovel to dig up the entire root clump.
2. Use a sharp knife or garden trowel to divide the clump into two or three pieces. Make sure each section has both stems and a healthy clump of roots.
3. Immediately replant the pieces into their new locations, into soil that has been well loosened and (if necessary) amended to improve its drainage.

Candytuft plants can also be propagated by stem cuttings, though rooting them can take some time.

How to Grow Candytuft From Seed

The native species of candytuft can be propagated by seeds collected from the seed pods left behind after the flowers fade. But named cultivars usually do not "come true" from their seeds, so vegetative propagation (see above) is the best method for propagating those varieties.

To grow seeds of the pure species, you can either start them indoors in small containers, or direct sow them into the garden in spring after all danger of frost has passed. Sow the seeds about 1 inch deep in well-loosened soil, then water well. Keep the seeds moist until they sprout, and continue regular watering until the plants are well established. Although mature plants can reach up to 18 inches, you can sow seeds about 6 inches apart to create a ground cover effect more quickly when growing from seed.

Potting and Repotting Candytuft

Candytuft falls into that category of plants that potentially can be grown in container, but rarely are. This is not a particularly attractive plant after the flowering period is concluded, and its fragrance is unpleasant to many people. And it is a slow-growing plant that will take some time to fill a spacious container.

Still, it's possible you may want to grow a specimen on a patio or deck where no garden space is available. If for some reason you want to do so, choose a fairly spacious, large pot with good drainage, and fill it with standard potting soil blended with sand or fine gravel to improve its drainage. Candytuft is best suited for growing alone in its own container rather than in mixed plantings.

Like any perennial grown in a pot, candytuft in a container will require somewhat more watering than is needed for garden plants. If you plan to overwinter the potted plant, move it to a sheltered location, or dig it into the garden up to the lip of the pot for the winter. Because it is slow-growing, you won't have to repot often—every few years is sufficient.

Overwintering

In regions where the plant performs as a standard perennial and dies back fully in winter, trim off the stems to 3 or 4 inches once frost has killed the leaves.

Some gardeners in cold regions (zones 3, 4) gently place pine boughs over the plants in late fall to shelter them from the cold, drying winds of winter. A 1- to 2-inch layer of standard mulch will have the same effect. In warmer regions, no winter protection is needed.

Common Pests & Plant Diseases

The most common disease issue with candytuft is root rot, which is common when the plant struggles in poorly drained, boggy soil. Badly affected plants will need to be removed. A variety of fungal diseases are occasion problems, including down mildew, powdery mildew, gray mold, rust, and fungal leaf spots. Rarely fatal, fungal diseases are more likely in humid conditions where air circulation is poor. If the disfiguring appearance is deemed intolerable, these infections can be treated with a fungicidal spray.

Most insect pests leave candytuft alone, though you may have problems with slugs, snails, and caterpillars.   

How to Get Candytuft to Bloom

Provided your plant is getting plenty of sunlight and is growing in well-drained soil, candytuft usually doesn't need encouragement to bloom profusely for several weeks in late spring and early summer. But you can extend the bloom period by fully deadheading the flower stalks after the blooms fade, and you may be able to force a second flush of flowers later in the summer if you severely prune back all stems by a full one-third of their length.

A light feeding with a phosphorus-rich fertilizer in the early spring can help maximize blooming. If a candytuft plant does not bloom as expected, it sometimes is because the plant is being overwatered—exceptionally rainy spring weather, for example, can cause a disappointing bloom season.

Common Problems With Candytuft

Candytuft is generally a fairly trouble-free plant, provided its growing environment is suitable. But you may witness these problems:

Yellowed Leaves

A candytuft plant that develops yellow leaves is often responding to conditions that are too hot, too wet, or too humid. While you can't control the temperature, watering in the morning only can help reduce the humidity that can cause yellowing leaves.

Stunted Growth

A plant that seems stunted may be suffering from clubroot, a fungal disease that affects members of the Brassicaceae family, including cabbages. If you dig up a plant with these symptoms, you usually can identify deformed roots. Affected plants must be removed and destroyed.