Scabious, or scabiosa, is a group of annual and perennial plants native to the Mediterranean region. About 80 species of scabiosa exist, but only a few are used as garden plants. Probably the best known is Scabiosa columbaria Butterfly Blue, which was named the Perennial Plant of the Year 2000 by the Perennial Plant Association. The cultivar name Butterfly Blue is appropriate since not only are the flowers filled with nectar, but they also resemble butterflies as they wave in the breeze.
Find a location that receives full sun to light shade. In their native habitat scabiosa grow in dry, sunny areas. They also do best in a neutral to slightly alkaline soil. If you live in an area with acidic soil, your scabiosa will benefit from the addition of lime to the soil. Be sure the location has good drainage. This is especially important in winter since the plants will not survive if waterlogged.
Before planting scabiosa, enrich the soil with organic matter. Plant bare-root plants or divisions so that the emerging buds are just below the surface of the soil. When planting container plants, be sure the crown is planted at the same level it was in the container to avoid crown rot. Allow 30 to 45 cm (12 to 18 inches) between plants. It is best to plant scabiosa early in the season to give the plant time to build an extensive root system. This will make it more likely to survive the winter.
Keep the soil moist during the growing season. Adding a light mulch will help conserve soil moisture and keep the plant's roots cool. Deadheading is essential to keep the scabiosa blooming. Butterfly Blue will flower repeatedly from mid-spring until autumn as long as finished flowers are removed promptly.
Do not cut back the basal foliage in the fall; instead remove any damaged foliage in the spring. The plant is hardy in all of the British Isles, but a winter mulch will help protect the plant from heaving during freeze/thaw cycles.
New plants can be created through division in spring or early summer every few years; this also serves to renew the plant and stimulate new growth. Keep in mind that these plants can be short-lived, so periodic replacement may be necessary. Since Butterfly Blue Scabiosa is a hybrid, any naturally occurring seedlings may not exactly resemble the parent plant.
Scabiosa Butterfly Blue is a versatile garden performer. The Perennial Plant Association recommends it for use in rock gardens or close to the front of the border, or in combination with other nectar-rich flowers such as coreopsis and dianthus in a butterfly garden. Butterfly Blue makes an excellent cut flower and is also used for its dried seedheads. Plant breeders have since produced a similar Scabiosa called Pink Mist (or Butterfly Pink).