Sarah's blog: Dahlia winners

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There’s a plant combination – Dahlia ‘Bishop’s Children’ and Verbena rigida – that has won the top prize in the garden this summer. The duo are planted in a band, both sides of the grass path on the veg and salad covered slope to the south of the greenhouse. 

The first flowers appear on both in mid July and I’m pretty sure they’ll still be going till the first hard frost at Christmas. The dahlias give you a good mix of stained glass, rich coloured flowers. There’s orange, deep red, crimson, apricot, ochre and classic ‘Bishop of Llandaff’ scarlet. Some have pointy tipped petals, others round, all bobbing above handsome black foliage.

As soon as there’s a hint of sun, they’re busy with butterflies and bees, an ideal pollinator plant, cheap and easy from seed. Their vase life is short (three days in the heat) but they work well as dinner table, single stems and I love them, all colours crammed together in a jamjar.

All you’ll need is these two packets of seed and you’ll get a potting bench full of plants. Both bulk up quickly after pricking out, to flowering size within three months. 95% of the dahlia seedlings have crimson foliage. There are a few bright green-leaved throw-backs which have all turned out to have acid-yellow flowers so I’d cast these out in future, but the rest are tip-top.


We have another patch of the dahlia in a sheltered spot in the cutting garden, which we’ve mulched six inches deep under compost for the last three winters and they’ve come up bigger and better each year. That makes this the bargain plant of the century, thirty or forty perennial plants for the cost of one packet of seed.

Verbena rigida is splendid too, way outdoing its taller relation, Verbena bonariensis. I like the density and brightness you get with the rigida form, which grows about 18inches/45cms tall. Like most tender perennial verbenas, it gently self-seeds, so is also ideal for softening gravel and paving stones. We also have it growing in exactly that position at Perch Hill with Rosemary ‘Foxtail’ and lemon verbena.

I am also mad keen on our forty foot run of Cobaea scandens. The flowers of this tender perennial triffid look like a small cup sitting on a saucer, and this summer, we have this flopping and frolicking over our new sandstone wall. We draped jute netting before we planted it which provides an all-important cobaea climbing frame.

Once Cobaea has really got going, you can pick the flowers, harvesting one or two stems at each of the chameleon stages. The flowers develop from soft ivory enclosed bell buds, which then open greeny-cream and quickly develop a wash of mauve. The purple deepens till it’s good, dark and rich; and then the flower drops, leaving the green calyx behind it to close into a Chinese lantern and protect the seed. Sear the stem ends in boiling water for 15 seconds and they should last five or six days. Even the twisty climbing stems last if you sear them and are good as an upper storey added to any arrangement.

Thanks for reading!