Home & People Colourful performers in the autumn border

Press, 19 April 1979, Page 15

Home & People Colourful performers in the autumn border

Some of the most colourful performers in the autumn border are the tall herbaceous sedums — curious customers that put on succulent dress in summer, then retire gracefully for the winter like any other hardy perennial. Most of them are natives of Europe, where they grow in rocky places, and all of them are easy to grow in any non-water-logged soil, preferably a light one, although Sedum spectabile, the most popular, has a marked preference for clay. Only a handful are worth garden space. One of these, Sedum populifolium, seems to have dropped out of commerce, but occasionally it is still seen in old gardens. This is a sub-shrub rather than a herb, having short, woody stems, with scaly brown bark, from which the annual shoots grow. The flowers are pale pink and the leaves are fleshy, shaped rather like those of a black poplar — hence the specific name. Sometimes it colours nicely in autumn before the shoots die back, but it is not really an exciting plant; it has a curiosity value, rather than an aesthetic one. Sedum rhodiola is much better, but it, too, is rare in cultivation. A native of Britain and Northern Europe, it has very hardy rootstocks that spend winter underground, and in spring sprout interesting, cabbagy rosettes that gradually elongate into normal flowering stems. The flowers are pink once again. The popular name of this plant is “roseroot,” be-

cause the rosettes, when dried, are said to smell of roses. Sometimes it is called Sedum rosea, and sometimes, because of minor differences between it and other herbaceous sedums, it is separated off into its own genus, as Rhodiola rosea. Seed catalogues are likely to list it under any of these names.

Another British native worthy of garden space is Sedum telephium, which is very much like a smaller version of the Japanese S. spectabile. Once again the flowers are pink, but in good forms the pink is a deep, rosy one, a much better colour than the washy pinks found in Sedum spec-

tabile seedlings that come up under the hedges. It is not a consistent colour; in some way the pigmentation is influenced by the weather, and in a cool or wet summer the pink is a much deeper shade. This year it is positively glowing; last year, after the drought and the prolonged hot weather, it was such a pallid colour that the plant was lucky to escape culling. I think many gardeners grow Sedum telephium without knowing what it is. At a casual glance it is not easy to distingiush from its taller cousin, but there are several clues that anyone can look for. One is that in S. telephium the stamens and petals are the same length. Sedum spectabile has stamens longer than the petals. The leaves of both are toothed, but in S. telephium the teeth are concentrated towards the apex, and the leaves are close to an oval shape.

S. spectabile has larger leaves, with fewer and bigger teeth, and they are technically obovate —■ widening sharply from the base into a reversed spearhead shape. Sometimes they are very close to being heart-shaped. Sedum spectabile has bigger flowerheads, too, and usually in a good form is a deeper colour, but it is a less tidy grower, having a tendency to flop about, and to show

ungainly lengths of bare leg.

Both species remain colourful for a long time. Even after the flowers fade the heads retain their russet-crimson colouring, and they go on looking bright into the winter, by which time they are mere skeletal remains. Selected forms have been given such names as “Autumn Joy” and “September Ruby,” but the most common one in this country, and probably still the best, is an old one named “Brilliant.” It sometimes comes true from seed, but more often its offspring contain a high percentage with washy flowers.

The Americans have a variety called “Iceberg,” described as “an interesting break with greenish white heads,” but I doubt if it has been introduced to this country. One plant that is in New Zealand, though it seems to have been spread through swapping by enthusiasts rather than by nursery propagation, is the variegated form of Sedum telephium, which has bright green or bluegreen leaves, liberally splashed with cream.

The variegation continues into the inflorescence, though the flowers themselves are dull pink. The plant seems to have no name. Sedum telephium “Variegatum” will probably do, though there are indications that it is not pure $. telephium but has some spectabile blood as well.

English experts do not regard it very highly. Alan Bloom, Britain’s leading authority on herbaceous plants, dismissed it as “not very outstanding” in a recent article in “The Garden,” and Christopher Lloyd, too, is a bit sniffy about it in his book, “Foliage Plants.” I can only assume that the clone grown in New Zealand is a much better one than the English version, because as usually seen here it is quite an outstanding and colourful border plant. If it has a fault it is that it is too emphatic to place easily; it must be among other bold, but nonvariegated plants. The other widely planted herbaceous sedum is Sedum maximum, invariably in its purpleleaved variety, “Atropurpureum.” Plain Sedum maximum is a dowdy thing, but the variety is a

bold and colourful plant year round, even in winter when it dies back to stocky rosettes in a sort of elephant’s breath colour.

In spring, a month or so after the rosettes begin to elongate, the young stems and leaves go a vivid plum purple, and as summer progresses this colour deepens, so that in some autumns the plant ends up close to a black-purple.

It if has a fault it is an over-vigorous constitution, for in a wet year it will make too much exuberant growth, and by midsummer will be flopping about among its neighbours like Eyore in a nor’wester.

One difficulty about growing these sedums is that although they all behave like normal herbaceous perennials, dying down in autumn and spring up in spring, they

have succulent stems and leaves, which is not a property normally associated with hardy plants. So they have an exotic appearance, and unless carefully placed can stick out like the well-known sore tooth among their conventional neighbours. In nature Sedum telephium grows on cliffs with sea-thrift (Armeria maritima) and forget-me-nots, a relationship that lays down some guidelines to their treatment in the garden: try them with the giant hybrid armerias and, perhaps, some of the lateflowering blue salvias. A Japanese anemone or two to add their unique combination of filigree work and exclamation mark would complete the picture.