Helianthemums galore Rock cover that is colourful

Press, 18 May 1984, Page 10

Helianthemums galore Rock cover that is colourful

W DIARY I

Derrick Rooney

Helianthemums, or “sunroses”, are often advocated for rock gardens, but I believe they are better placed in borders. They are small shrubs which come in a range of colours covering most of the spectrum except the blue end, flower prolifically in late spring and early summer, and continue to produce sporadic bursts of flowers throughout the season.

They like the soil to be well drained, but aren’t otherwise fussy, though they tend to live longer and flower better in hard conditions.

If you have a piece of rocky hillside that you would like to see swathed with colour for a good part of the summer, then helianthemums are just the sort of thing you would like.

Named varieties are legion, and are easily propagated, in the main, by cuttings. But some of them are hopelessly muddled up in' the nursery trade, and to be sure of getting what you want it is necessary to go to a specialist, or to buy the plants in flower. Don’t go by the label alone.

Recently, I bought two attractive helianthemums from a garden centre; one was of erect habit, with green leaves, the other of semi-prostrate habit, with greyish leves.

Both were labelled “Ben Afflick,” which they patently were not. In due course one bore pink flowers, the other white ones. “Ben Afflick” has

orange flowers, but your average gardener probably doesn’t know that and the average nursery staff probably don’t know it, either. Thus mistakes become self-perpetuating. Fortunately, not all the classic helianthemums have been muddled. Two survivors, which are usually found true to label, are golden oldies: “Jubilee” and “Mrs C. W. Earle,” yellow and red respectively, with double flowers like little overblown roses.

Both of these go back a long way further than I do. I’m not sure whose jubilee the former commemorated; it might have been Queen Victoria’s. I like this little shrub; I was sorry to see it go in a reorganisation of my rock garden a few years ago, and delighted to obtain it again last summer. The little flowers are literally crammed to bursting point with bright yellow petals, and an occasional flower has a red streak, or is all red—a sure-fire way of identifying the variety.

Mrs Earle was a redoubtable Victorian gardening lady who wrote “Notes from a Surrey Garden” and other books in which she discoursed not only on gardening (very knowledgeably) and cooking (ditto) but on how little girls and boys ought to behave and be educated. Her books remain entertaining reading, at least in the chapters dealing with plants and food, and the

sun-rose which bears her name likewise retains its place near the head of the field.

A delightful prostrate pink veronica is also named for her; more’s the pity that the nursery trade often botches her name by adding an “s” to it.

Among single helianthemums, the Ben series, raised in Scotland and named after Scottish peaks, is outstanding. These go back, mostly, to the period between the world wars. About 30 were named altogether, and over the years most of the better ones have been imported to New Zealand. Some seem to have disappeared in recent years—the charming “Ben Alder,” for example, is sadly missed; it had flowers described as “terracotta,” but closer to the colour of a clay pot with milk coffee spilt over it. I grubbed out a geriatric plant of this some years, ago, during a reorganisation of part of the garden, and was mortified to discover afterwards that I could not replace it. “Ben Ledi,” which has rich crimson flowers, and “Ben Hope,” hot pink, are still available, and I have another Ben, the name of which I have misplaced, with brick red flowers.

Of these, I think I like “Ben Ledi” best, for its vigour, its cushion habit and the richness of its colour. But don’t put it in the rock garden; grow it in a border. Also suited to the border is “Wisley Primrose,” a vigorous bush which grows erect, reaches a greater height than most helianthemums, and decks itself with large, pale yellow flowers most of the summer.

All these varieties are selections or hybrids of the common sun-rose, named

Helianthemum nummularium or H. vulgare, depending on which authority you accept (the Flora Europea opts for “nummularium”). Gardeners and horticulturists invaribaly lump in these helianthemums with Mediterranean flowers, and tend to forget that they are natives of Britain, too. Another British native which I have grown, with a great deal of enjoyment, in my rock garden for some years is Helianthemum chamaecistus.

According to the Flora Europa this name is just a synonym for the common sun-rose, but in the garden it certainly looks and behaves like an entirely different species, and it comes true from seed.

In habit and appearance it resembles, when out of flower, one of the carpetforming thymes. Once a year, and occasionally twice a year, I trim round the sides of its dense, green mat with hedge shears; if I didn’t it would seen bulldoze everything in its path. During late spring and early summer the whole plant is spangled for many weeks with intense yellow flowers.

Helianthemum apenninum, from Southern Europe, is another good one—in most of its numerous forms. Despite the name this is a widespread species, usually of prostrate habit but occasionally erect, and almost invariably ith grey leaves. Both white and pinkflowered forms are known, but I have grown only white ones. A few years ago I grew a form with small, hard grey leaves, stiff branching, and an almost cotoneaster-like habit of flinging itself at the nearest rock.

Its pure white flowers were about the size of a 10c piece. It grew well for a time, and even seeded itself, but both it and its seedlings slowly faded away, I suspect through lack of hardiness.

I live in fear that a similar fate will befall its successor, which has larger ■leaves, more white than grey, and a soft habit where the other was hard. The

main branches hug the ground, and leafy shoots rise vertically from them. Raised from Spanish seed, it has throughout winter the bedraggled air of a plant yearning for warm, sunny hillsides; but come spring it bursts forth, white upon white, once again. The flowres, which are yellow at the eye, have the texture of rumpled silk. At the height of the season each one may be the size of a 50c piece, but as summer progresses into autumn the flower size of the successive waves of blossom decreases. Last week there were still a few miserable lOc-sized blooms.

Alas, this plant has, in contravention of the family rule, proved almost impossible to propagate from cuttings, and' so far has set no seed. Another choice white species, which I have grown for some years, also sets no seed, though it will grow very readily from cuttings, thank goodness. This is Helianthemum umbellatum, or, as we must now call it according to the Flora Europea, Halimium umbellatum.

The genera helianthemum, halimium, and cistus are all closely interconnected, and numerous intergeneric hybrids are known in the group.

An amateur—and even a professional — gardener could be excused for having difficulty with them, so Halimium umbellatum has been about in New Zealand alpine nurseries under a variety of names—the original importer called it “Helianthemum umbellatum,” a Southland nursery has listed it as “Helianthemum species,” and a Timaru grower lists it as “Cistus species”—but appeals in her catalogue for customers to tell her the correct name. If she reads this column, she has it.

The plant, incidentally, is a loose-growing, erect shrub with narrow,, rosemary-like leaves, and in the fullness of time it may reach a height of 60cm. Throughout summer and well into autumn it produces waves of glistening flowers.