Dianthus is a colorful perennial bloomer that includes about 300 varieties, including the familiar sweet William, carnation and pinks. Sizes range from petite plants under 6 inches in height to scene-stealing 3-footers. Depending on the variety, foliage may be grayish-green to bright green. Blooms may be bright or pastel, some varieties may be bi-colored or multi-colored and some have a light, spicy scent. Its versatility and carefree nature make dianthus a popular plant in the home garden.
Plant dianthus in well-drained soil, where the plant will be exposed to at least six hours of sunlight per day. A lack of sunlight will produce tall, lanky plants with sparse blooms.
Install a wooden or bamboo stake for tall dianthus varieties. Drive the stake into the ground at planting time or when the plant is small, as waiting until the plant is large may damage the roots. Tie the dianthus stem to the stake with a soft garden tie or strip of pantyhose.
Water dianthus during hot, dry weather, giving the plant an inch of water every week it doesn’t rain. Otherwise, dianthus is drought-tolerant and requires little moisture.
Spread one-half to 1 inch of compost over the soil every spring. Top the compost with 2 inches of mulch. The compost and mulch will enrich the soil, conserve moisture and deter weeds.
Pinch off dianthus blooms as they wilt and fade, as removing the blooms will cause the plant to continue flowering. Leave a few blooms on the plant at the end of autumn if you want the dianthus to self-seed.
Cut dianthus back to 1 to 2 inches above the soil after the first hard freeze in autumn. Spread 2 to 3 inches of mulch around the plant to protect the roots from winter cold.