Bachelor buttons

Wildflowers and weeds Bachelor buttons

By shauna dobbie and dorothy dobbie

Perennial bachelor button. Annual bachelor button.

Annual

Who doesn’t like bachelor buttons? A tuft here or there growing out of the pavement reminds you that, no matter the will of humans, nature will always win in the end. They pop up in the most unexpected places, you think they must be native. But they aren’t.

Centaurea cyanus is a European annual. They like sandy loam soils and are often found in and around grain crops, giving the flower one of its many common names, cornflower. Other common names are bluebottle, blue bonnets, brooms and brushes, corn blinks, ladder love, logger heads, miller’s delight and witch bells.

Natural occurrences of bachelor buttons, where the plant has long occurred and isn’t a garden escapee, have declined steadily over the past 100 years owing to herbicides used by farmers. The poor flower relied on its good looks for millennia and never developed such species-preserving traits as long-lived seeds. Nonetheless, it is pervasive in warmer temperate areas, even being called invasive in BC and a couple of states to the south.

One of the curious things about bachelor buttons is the cyan-blue colour in its Latin name. Many of nature’s blues are ephemeral: the blue of a butterfly’s wings is a trick of the light, the purply-blue of coloured beans and broccoli disappears when you cook them. But the blue of bachelor buttons survives drying and maintains its blueness; dried bachelor buttons in King Tut’s tomb had lain there for over 3000 years and lost little of their colour.

They are edible but don’t taste fantastic; still, the flowers do add a striking blue to a salad. They can be used to make dye or ink, or they can be decocted to make a rinse for eyes. They do have some effect as an anti-inflammatory, but other plants are better for it.

There are cultivated varieties you can grow in shades from almost black to almost white, with pink and lavender in between. Often seed companies will throw them all together in one package or add them to a meadow mix.

If you decide to plant some bachelor buttons, sow seeds in early spring in a full-sun area. They aren’t fussy as to soil but do better in alkaline soil, and once established are drought tolerant. Sow directly in the garden as soon as you can get a trowel in, about 2 inches apart, and cover seeds with ½ inch of soil.

Perennial

Have you ever heard of the perennial Centaurea montana?

As lovely as the annual C. cyanthus is, the perennial might better be called enchanting with its delicate star-shaped petals reaching out in an airy circle above a darker, more violet centre.

Native to Europe, the perennial bachelor button has gained bad reputation in some parts of the country and is considered a noxious weed in British Columbia because it will self-seed and has persistent and stoloniferous roots. It is hardy in Zones 3 to 8, although it is less invasive in colder regions. It likes a sunny location but will also survive in leafy shade.

Because this flower has escaped gardens in many regions, it is often thought to be a native plant but there are only two centaureas native to North America. One of them, C. americana, also known as the American starthistle and as basket flower, occurs in the South-Central United States and North East Mexico. C. rothrockii, its cousin, is showier with similar pink to mauve petals and a creamy centre, but it’s flowers are larger (five inches across) with longer petals that sometimes recline.

An unusual C. montana is ‘Amethyst in Snow’. It has a circlet of creamy petals surrounding blue-purple centre.

Unlike annual bachelor buttons, the perennials will not steal the show in the garden. Two- to three-foot stalks support a single delicate flower; the most rewarding way to see them is up close. d