In my last post, the photo of Cerinthe flowering ridiculously early certainly generated a lot of comments. It turns out that this plant is a favourite with many folks and deservedly so.
A comment left on that last post asked for advice on growing Cerinthe from seed saved last year. I have to say that it couldn't be easier.
At this time of year (late spring), you can sow them outside, direct into finely raked soil. Water the soil first and cover the seeds with a bare quarter inch of soil. You can also do this in autumn (late September) to get them off to an early spring start.
On the other hand, if you only have a few precious seeds, start them in small pots or modules indoors: soak seeds overnight to break down outer casing, sow at same depth of seed (about 2 - 3 mm deep) into free draining soil, wait 7 - 14 days for germination, let the seedling grow a bit before potting on; at about 3 inches tall, with 3 to 4 leaves, harden off and plant outside, leaving about 40cm between plants. They're a Mediterranean plant and their waxy blue-green leaves are a big clue as to where to site them - a nice warm spot with plenty of sunshine will suit them best and see them thrive. The soil doesn't have to be anything special, but must be well drained. Mine grow on top soil over London clay and usually reach about 50cm high.
The stems can get a bit straggly in time and, as the drooping flowers are the whole point, it's quite nice to just support the stems a bit by staking, if you can be bothered. If you plant them closer together, they'll prop each other up but won't look as nice.
They flower over a long period. If you're lucky, as they develop you'll get blue-green leaves with deep blue bracts surrounding a purple flower. This isn't always the case though; I've had Cerinthe with grey-green leaves and pink flowers in previous seasons.
Remember these plants are really good self-seeders; seedlings will pop up every year once you've had one plant in your garden. Every purple flower has two fat seeds inside; not all will germinate but it's a good precaution to collect the seed before it drops.
Like Marigolds, etc, Cerinthe seeds can also be sown in the Autumn for earlier spring flowering. They are hardy plants and, once established, will pretty much cope with anything. Slugs don't like them. This is the first time that mine have come through the winter. The warm extended autumn of 2011 meant that I pulled the ropey looking plants much later than usual, giving the seeds time to drop. The cold and rain of 2012 meant that the conditions weren't right for germination until late summer so my plants were still relatively young by the time winter arrived and were left in situ. A few gangly sorry looking specimens were put out of their misery earlier this year but the healthier ones were left - and I have early spring flowers as a result. It's lovely to see as other self seeded flowers (nasturtiums, sunflowers, marigolds, orach) are only just beginning to get going.
They're not edible but are a real magnet for bees as the purple flowers are a good source of nectar. They also make an interesting cut flower and will last better if you sear the ends of the stems in hot water for 30 seconds. Grow them with Escholzia (Californian Poppies), Atriplex rubra (Orach), Verbena bonariensis, Bupleurum rotundiflorum and Linaria (toadflax) for a colourful display.
I hope this post has been useful and will inspire more people to grow these lovely plants. Seeds are available all over the internet, although they're unlikely (but not impossible) to be found in garden centre or supermarket seed racks. I started my Cerinthe stock with one small plant bought from Sarah Raven's nursery at Perch Hill and saved the seed each year thereafter.