True blues that climb or recline

After a very chilly August, September has mellowed and the garden wears a relaxed air. One group of plants suits this gentle spell, separating an unsettled August from a dank November ahead. The stems lean informally, topped by clusters of fragrant blue flowers with petals that turn back and invite the bee and butterfly to dine. These are forms of Clematis heracleifolia (or their near relatives) and they always delight me now with their hyacinth-like clustered flowers at the top and in whorls down the stems. You can get weeks of flower and somehow they seem to suit this winding-down of the year.

These floppy clematis with a deciduous habit come into their own in August and September and they can be used with herbaceous plants. In the wild, though this species is found in parts of central and northern China, they do best in good soil in my garden, although they wouldn’t enjoy being waterlogged in winter. The flowers are dioecious, with males and females on separate plants, and fragrance is the bait that lures in the much-needed pollinator.

C. heracleifolia refers to the lobed Heracleum-like foliage and the species came to Britain in 1837. A darker form that used to be called C. heracleifolia var davidiana arrived in 1864, named after the missionary Père David who first described it growing near Peking — now Beijing. It is now called C. tuberosa, but still sold under the old name. One of the best known forms, ‘Wyevale’, was a 1955 darker blue selection with ruffled flowers from a Mr Williamson of Hereford. It was named after the Herefordshire nursery who promoted it.

The great French nurseryman, Victor Lemoine, hybridised C. tuberosa and C. stans in 1900, and this hybrid was named ‘Crépuscule’. This has very tubular flowers in palish purple-blue and was probably bred for the cut flower market. Apparently the flowers of herbaceous clematis last well in water. I have just seen 'Crépuscule' flowering in the late Alan Bloom’s Dell Garden at Bressingham in Norfolk, and doing very well. C. stans is often sold too. However Christopher Lloyd’s description, in his excellent monograph on Clematis, sums it up as having “a spitefully non-contributory off white, skimmed milk colouring.” Say it as it is, Christopher, it’s always the best way forward! Shame I didn’t read Lloyd’s pithy description before I planted it!

I’ve just seen another growing at Bressingham Hall in Norfolk; the garden of the late Alan Bloom. It was first called ‘Bressingham Bluebird’, but then renamed ‘Alan Bloom’ on the occasion of the great man’s 90th birthday. I spent the morning with Alan on that auspicious day and he was less than pleased, even more so when it became ‘Alblo’. However it is a very good dark-blue form, selected from ‘Wyevale’, and one that I want to find and grow.

I already grow C. heracleifolia ‘Cassandra’, a strongly-scented bluer form with a shorter, less lax habit than most. This newish clematis originated at the Staudengärtnerei Gräfin von Zeppelin nursery in the small German village of Laufen. This to me is the finest of all, because it’s tidier in growth and sparkily vibrant, rather like journalist Cassandra Jardine in whose memory I planted it.

Herbaceous clematis are easy to prune. Cut them back after the stems and leaves have faded once spring arrives — usually in March orApril. I’m told that the easiest way to propagate is to divide a mature plant, by cutting through the entire root-mass, in very early spring. The ground should be workable and the plant not yet in active growth.

There are other forms of non-climbing clematis and they include forms of Clematis integrifolia a summer-flowering species originally from S.E. Europe. I grow this close to roses and it pops up here and there. Silky seed heads follow. There are named forms and ‘Yvonne Hay’ has dark-blue flowers with narrow petals that mimic the flowers of C. alpina. It all proves you don’t have to climb to be a clematis. Sometimes reclining is enough.