When to Plant Scabiosa: Indoor Seed Starting, Planting Out After Frost and Fall Sowing for Pincushion Flowers

Scabiosa, or pincushion flower, is named for the domed flower center packed with stamens that look like pins in a cushion (NC State). Three kinds are common in gardens. Sweet scabious, S. atropurpurea, is a Mediterranean plant grown mostly as an annual (NC State). S. caucasica, from northeast Turkey to the Caucasus and northern Iran, is a perennial for cooler gardens (NC State). S. columbaria includes the popular perennial 'Butterfly Blue', which the Almanac says was Perennial Plant of the Year in 2000. The genus name comes from the Latin for "the itch," after the rough leaves (NC State).

When to plant scabiosa

Use our planting calendar to find your last spring frost and count back 4 to 8 weeks for an indoor start. Johnny's grows seedlings cool, at 50 to 55°F, so they don't stretch.

How to plant scabiosa

Garden Design works compost into heavy clay at planting to improve drainage, and NC State and Garden Design both name root rot in wet soil as the main risk.

Watering, deadheading and cutting

• Water the first year. Garden Design gives about an inch a week in the first year; older plants are more drought tolerant but should never sit in soggy soil.
• Deadhead to prolong flowering (NC State, Almanac), or leave a few seed heads for interest (NC State).
• Cut for the vase. Johnny's harvests S. atropurpurea when the flowers are almost fully open, and the Almanac dries stems by hanging them upside down in a dark place for a couple of weeks.
• Stake taller kinds before they lean (Almanac, Johnny's).

Scabiosa in containers

The Almanac says smaller varieties grow well in containers but taller ones are less suited. Garden Design names compact kinds such as 'Butterfly Blue' for pots. Our reading is to use a pot with drainage holes and a free-draining mix, since wet roots are the main risk (NC State).

Fall and winter

• Keep perennial crowns dry. NC State says S. caucasica should be protected from wet winter weather with a light, dry mulch of hay, straw or evergreen boughs; Garden Design says scabiosa is particularly intolerant of wet winter soil.
• Cut back, but not too far. Garden Design cuts perennial stems back to the bottom leaves in fall and leaves the basal foliage, which stays semi-evergreen.
• Let annuals self-sow if you want them back. NC State says S. atropurpurea can self-seed in good conditions and is considered an invasive weed in some countries, so deadhead if you don't want volunteers.
• Refresh perennials by dividing every 3 to 4 years in early spring (Garden Design).

Pests and problems

NC State calls aphids and mites minor issues and lists no known problems for S. caucasica. The Almanac adds whiteflies, powdery mildew and root rot, and says deer don't like pincushion flowers; NC State also lists deer resistance. Most trouble comes from wet soil, so drainage matters more than spraying (our reading of NC State and Garden Design).

Scabiosa in the vegetable garden

NC State says the flowers attract butterflies and hummingbirds, and Johnny's grows sweet scabious as a cut flower. That makes a short row of scabiosa a good fit for a cutting strip beside the vegetables, alongside zinnias, cosmos and snapdragons, or with coreopsis and dianthus, which also want sun and drainage (our reading). See also flowers that attract beneficial insects.

Frequently asked questions

When should I plant scabiosa?

Plant transplants after your last frost, or sow seed outdoors in spring once frost danger has passed (Almanac, NC State). In mild-winter areas you can also sow in late fall (Garden Design).

When do I start scabiosa seeds indoors?

4 to 8 weeks before your last frost (Almanac); Johnny's uses 4 to 6 weeks. Seed sprouts in about 10 to 12 days at 65 to 70°F (Johnny's).

Should I cover scabiosa seed?

Only lightly. Johnny's barely covers it because light aids germination; the Almanac covers it with 1/8 to 1/4 inch of soil.

Is scabiosa an annual or a perennial?

Both kinds exist. Sweet scabious (S. atropurpurea) is usually grown as an annual, while S. caucasica and S. columbaria ('Butterfly Blue') are perennials (NC State, Almanac).

How do I keep scabiosa blooming?

Deadhead spent flowers (NC State, Almanac) or cut them for the vase. Johnny's also sows every 2 to 3 weeks until late spring for a longer supply of stems.

Why did my scabiosa rot?

Wet soil. NC State says it will not tolerate wet feet and recommends good drainage; Garden Design says it is especially intolerant of wet winter soil.