Dianthuses can be annual, biennial, or perennial. Dianthuses genus covers over 300 species; as a gardeners’ favorite, they have been extensively bred and hybridized. Most varieties are 10 to 20 inches tall, but dianthus varieties range from annual creeping ground covers to 24-inch (or longer) long-stemmed perennials (such as carnations) suitable for cutting. TVibrant coneflowers that are drought-tolerant and easy to grow.