Many good plants do not get into nurseries

Press, 14 February 1986, Page 14

Many good plants do not get into nurseries

Gardener’s J DIARY

Derrick Rooney

Without being too chauvinistic about it, I can confidently say that some of the finest ornamental foliage shrubs are home grown — and that many are underappreciated by New Zealand gardeners. New Zealand is well

endowed with woody plants, with more than 700 species of trees and shrubs from a total flora of about 3500 species. Yet probably no more than about 50 are readily obtainable from commercial sources, and the number of species that are promoted with any enthusiasm could be counted on the fingers. Commercial considerations dictate that the “popular” native shrubs are those which are easy to propagate in bulk and look good in planter bags. There are many good plants that don’t get into nurseries. Brachyglottis (formerly Senecio) eleagnifolia “Joseph Armstrong” is one. Brooding, dark green leaves, lightened by creamy white marbling on the veins and brownish buff to mentum underneath, make this one of the finest foliage plants you could see anywhere, maybe more handsome than any of the rhododendrons. Admittedly it’s a pig of a thing to propagate but it’s in a few gardens (not mine, alas) so there must be a way. Olearia macrodonta (a natural hybrid) is fre-

quently offered but one of its parents, O. ilicifolia, a superior plant, is seen less often ’ and the extraordinary O. lacunosa, with its long, narrow, green leaves, hardly ever. The hybrid of these two, known as Olearia mollis, also deserves a run.

In some instances overfamiliarity with native shrubs can blind gardeners to their virtues. That must be what has happened with the cassinias, a small genus of shrub which, like olearia, belongs to the daisy family. Cassinias are great colonisers which spring up in abundance on cleared or overgrazed ground wherever the habitat is suitable for them, and their vigour, plus their unpalatability, often has them regarded as pastoral weeds. Gardeners really ought to be grateful for the existence of such attractive and easily grown shrubs! One of the best is the common North Island “cottonwood,” a plant mostly of coastal dunes which is, in its best forms, ornamental and trouble free.

It is rated as half-hardy but a lot of specimens are growing at Ham so it can be presumed to be hardy at least as far south as Christchurch. A small specimen in a planter bag came through last winter in my plunge bed, and is now in my garden. Admittedly it was in the shelter of a hedge, but it did spend a lot of the winter frozen solid, so I have hopes it will survive. The botanical name of this shrub is Cassinia retorta — so called because the leaf margins are rolled under. When well grown this cassinia has striking silver-white shoots and an appealing tall, willowy habit; but I can’t recall ever having seen it offered for sale in a commercial nursery. A good form was distributed some years ago for some public plantings by the Ministry of Works nursery, but I have no idea whether the stock has been maintained.

Cassinias have clusters of small, often dirty white flowers that are no great asset, except perhaps in the case of the tender C. amoena, a plant of the far north which would not survive in many Canterbury gardens. The five species which were listed in the 1961 Flora have been reduced to three, C. fulvida, C. leptophylla, and C. vauvilliersii not being regarded as specifically distinct

These are now united as one species, under the latter name. They are plants of inland and subalpine regions. Cassinia leptophylla is the name previously used for plants with silverwhite young shoots, and C. fulvida and C. vauvilliersii were used for plants with yellow or yellowish shoots, C. fulvida having been regarded as the subalpine entity. However, as has been confirmed by observations both in the wild and in gardens, you can get a range of stem colours from bright yellow through to green and silver-green from any one plant. My plant, which came originally from the Cass region and has the brightest of yellow stems, is the -form previously known as C. fulvida var. montana; occasionally its seedlings appear in the garden and they almost always have green or whitish shoots. Their behaviour in the wild seems to be similarly unpredictable. In some areas the plants are predominantly yellow, in some they are predominantly green, and in some the colours are all mixed up. If you want a plant for the garden you might as well look around for a good one and take cuttings. These usually strike quite freely if taken in autumn.