Growing Bachelor’s Buttons

Credit: schnuddel/iStockphoto


Q: I just love bachelor buttons; however, they do not like to live with me. According to the seed packages that I purchase, they are hardy and can grow anywhere. Yet, whenever I sow them into my garden, they never come up in any great quantity to be seen (only one or two plants at a time). This problem seems to be ongoing…Do you have any ideas?

Bachelor’s button (also called cornflowers) makes such a great cutflower and works well in a mixed border – no wonder you keep trying it. Centaurea cyanus is an annual that thrives in full sun with good air circulation to prevent foliage disease (powdery mildew). It should be relatively easy to grow from seed, but covering the seeds with soil is important as they need darkness to germinate.

Starting outdoors
Sow seeds directly in the garden, 1 cm (1/2 inch) deep in September, March or April. Plants will bloom in the spring from a fall or early spring sowing. Keep the seeded area well watered until the seeds germinate (about ten days). Thin seedlings to stand 15 to 25 cm (6 to 10 inches) apart. Sow at several different times to extend the season of bloom.

Sowing indoors
In March, partly fill individual pots (as they resent being transplanted) with seed-starting soil. Add a seed to each pot and cover it with 1 cm (1/2 inch) of soil. Keep the soil moist but not wet until the seedlings emerge. Once they have several sets of true leaves, gradually harden them off (expose them to outdoor weather under a covered area or during the day only for a week). Plant them outdoors in early May (in most parts of B.C.)

Add a scattering of dolomite lime to the soil before planting, as this species prefers slightly alkaline (“sweet”) soil. Water plants in with a soluble fertilizer to get them off to a strong start. Staking of tall cultivars is not always necessary as their stems are wiry and quite strong. When you water the plants, try to keep the foliage dry and water only the roots. Deadheading is important to extend the season of bloom.

If you like the structure of the bachelor’s button flower, you might also want to try the perennial mountain bluet – Centaurea montana – which is hardy to zone 3. It’s a bit floppy, so I’ve grown it in front of a shrub where it can flop outwards and looks less awkward. Its flowers are exquisitely arranged – definitely worth a closer look! The flowers of both kinds can be dried and make great cut flowers. Sadly, the giant knapweed, Centaurea macrocephala, is becoming an invasive plant in high elevation rangelands in some parts of the Pacific Northwest and it’s difficult to control, so I’d avoid that one.