Tuesday, 10 July 2012

Coreopsis

I have to confess right away that the main coreopsis I have grown is pink. This puts me in a poor position for defending the yellow daisies. The one I grew was 'Heaven's Gate', a cultivar of coreopsis rosea, and it was such a perfect colour I was willing to keep buying it year after year, since it never survived winter in Northern England.

It was only after one year when I planted some out in front achillea 'Summerwine' that I really saw what it could do - the dark raspberry eye of the coreopsis matched the achillea perfectly - and on closer inspection, I noted that the flowers on the achillea were paler at the centre, like the coreopsis in reverse. Not planned - but satisfying. Their habits were a good contrast - the achillea stands in a clump, while the coreopsis is more wispy, with thin stems and leaves but plenty of flowers. (Like coreopsis verticilliata, below.) Unfortunately, no picture, but here's the two items in question, see for yourself:

Coreopsis rosea 'Heaven's Gate'

Achillea 'Summerwine'
I don't know why I couldn't overwinter this plant. It is a native of eastern North America, and can be found as far north as Nova Scotia. Apparently it likes damp, and grows on the edges of marshes. It's a mystery, although I do have to say that it flowered profusely for me each summer, and it's fun watching the tiny dots of the buds unfurl into the daisy flowers.

The botanic name for this plant is coreopsis rosea Nutt., which stands for Nuttall, after Thomas Nuttall, another British plant hunter. He seems to have discovered several species of coreopsis, including the annual c. tinctoria, which has a dark centre. It is the parent of modern cultivars such as 'Roulette', which is showy, although I think even the original plant is attractive, and would look good with heleniums:

coreopsis tinctoria
Coreopsis tinctoria, photo by Cory Maylett, from Wikipedia Commons
Another popular garden variety is c. verticilliata, or the whorled coreopsis. It has small, fine leaves and smallish lemon-yellow flowers, and the plant as a whole is very attractive. It also has the distinction of being first described by Linnaeus, which means it can call itself coreopsis verticillata Linn. From it we get such popular garden varieties as the pale lemon coloured ‘Moonbeam’ and brighter ones like ‘Zagreb’.

Coreopsis verticillata, Hortopedia Commons, photo by  Alfred Osterloh 
Coreopsis, by the way, comes from the Greek words κορις (koris), meaning "bedbug," and ψις (opsis), meaning "resemblance", referring to the shape of the achenes or fruits. When you consider that the common name is tickseed, because the seeds supposedly look like ticks, you have to admit that this a plant with a PR problem.

It doesn't help that coreopsis is, let's face it, yellow. Of course, there are all sorts of colours of coreopsis now, ranging from "Limerock Ruby" (red, of course) to Creme Brulee (palest yellow). But why not take up the challenge?

You can go the tasteful route and plant the paler varieties, such as c. verticillata 'Moonbeam', which also has the delicate habit that its common name, thread-leaf coreopsis, suggests. Crocus suggests planting it with the grass stipa tenuisssima, which is delicate and lovely to run your fingers through, like silky hair. 'Moonbeam' is very free-flowering and easy.

Another way of managing the bright yellow might be to plant both a paler yellow like 'Moonbeam' and a bright sunny one like 'Zagreb'. At Hadspen (a famous English garden) Nori and Sandra Pope used to do that in their colour-themed borders, the paler on one side and the darker on the other, to tone. (See their book Colour by Design for pictures and inspiration.) You could also include some bidens as an edging plant, since it not only has similar flowers but is a relative. 

With the strong-coloured coreopsis grandiflora, I would be tempted to say the hell with it and go for a blaze of yellow. After all, the varieties have names like 'Sunfire', 'Sunny Day', and 'Early Sunrise' - so put that solar power to work for you.

Coreopsis grandiflora 'Early Sunrise'
'Early Sunrise' has double flowers like a carnation's, and 'Sunny Day' looks like a bright yellow cosmos, while 'Sunfire' is single with a splotch of purple at the bottom of each petal - ideal with gaillardias.

As you might expect from the name, all these have larger flowers than the verticilliatas, and are less delicate. In a border with rudbeckias, heleniums and some dark blue salvias and liatris, they should be fine. You could start with yellow geums until the coreopsis kick in mid-summer.

Or, for a real kick of sunny innocence, plant some bright yellow coreopsis with the tiny white daisies of chamomile (anthemis), green-flowered nicotianas, and yellow or orange crocosmias. Zingy enough for anyone, and cheerful enough to make even the most hardened garden snob smile.

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