Hypericums flower over a long period

Press, 16 December 1988, Page 10

Hypericums flower over a long period

Gardener’s! J DIARY

Derrick Rooney

Apart from roses, which do not really count as shrubs, there are not too many woody plants flowering at this time of year: a few spiraeas, Marlborough rock daisies, tail-end cistus, deciduous ceanothus in my garden, that is about it — apart from the hypericums, some of which are just coming into flower, while others are in full swing.

I grow a few of the smaller hypericums, and consider them good value. They are always neat, almost free from pests and diseases, unfussy about soil, and flower over a long period. One or two are a trifle generous with their seedlings, but these are easily pulled out. Hypericum olympicum is one of the best; it has tidy foliage and maybe the largest flowers among the small-leaved hypericums. The original home of this shrub was in SouthEastern Europe and West Asia (its name is taken from Mount Olympus in Greece), but it has been in cultivation for a very long time; it was grown at the Chelsea Physic Garden back in 1706. There are several cultivated varieties, of which the best-known is “Citrinum” — the form with pale yellow flowers, a colour which shows up well in the garden. A low, compact bush, this grows no more than 25cm high and about 60cm across: Its stems are usually unbranched and the flowers appear in terminal clusters of up to five. Several other small hypericums are worth space, even in the smallest gardens. Top cat among them is, I should think, H. rhodopaettm, which, as you might infer

from the name, is native to the Greek Islands (and other parts of South-East-ern Europe). One of the gems of the rock garden, it is a low, tufted shrublet with pale, but bright, yellow, biggish flowers in small clusters at the ends of short, hairy stems which often die back in winter. The leaves, also hairy, are almost blue. A recent visitor to Christchurch, Tony Schilling, curator of Wakehurst Place, where Britain’s national collection of hypericum species is held, rates this as the best of the small ones.

If you like heaths, you will want to grow H. coris, which looks just like a miniature erica — until it flowers. It likes full sun and gritty soil, and is a dense, twiggy shrublet with tiny, dark green, narrow leaves in clusters. The flowers are 2cm across and appear along the stems in late midsummer. The colour is pale, glowing yellow. Hypericum balearicum is a distinctive minishrub from the Balearic islands in the western Mediterranean. In Britain, where it was introduced to cultivation from Majorca early in the eighteenth century, it is regarded as too frosttender to grow outdoors except in the mildest counties.

With its reddish stems and warty green leaves, it is quite unlike any other

hypericum, and could hardly be confused with any other species. Its biggish, bright yellow flowers appear at the ends of the stems in late midsummer. There are others, only some of them of high quality, for this is a genus of legion species, among which are infamous weeds belonging to the “St John’s Wort” group. New Zealand has several indigenous species but none of them is gardenworthy, although I grow H. gramineum in a container, as a curiosity: it has probably the smallest flowers of all hypericums, and neht little leaves to match them.

The “St John’s worts” — the H. perforatum group — are widespread weeds in New Zealand. Others to beware of include H. androsaemum, the “tutsan,” which has attractive fruits, but is a persistent and toxic weed, and H. calycinum, the so-called “Rose of Sharon.” This is an attractive, low shrub with large yellow flowers, but it can spread aggressively by runners and colonise large areas. Beware also of H. camtschaticum, which has big, bold, glaucous leaves and persistent, red, underground stems.

I made the error of admitting this to my rock garden, where it looked quite splendid for a season, then took over. Ten years later, I have not eradicated it. “Hidcote” and “Sungold” are good things among the larger hypericums; both grow to about 1.5 m and flower for weeks and weeks in summer. "Hidcote” is a slightly lighter shade of

yellow, but there is not much to choose between them. H. leschenaultii grows taller and has deep golden yellow flowers, but does not succeed in very cold gardens. Among the remaining small ones, do not overlook H. reptans, a tiny creeping bushlet with bright yellow flowers.

This is a rock-garden plant. Another name which appeared in garden centres this spring is Hypericum cerastioides. This was attached to plants, grown by a North Island distributor, which appear to be H. rhodopaeum under another name. A rose etc ...