Flora of New Zealand Series

Perennial, usually deciduous shrubs, sometimes scrambling or lianoid; stems armed with epidermal prickles, acicles, bristles, or simple or glandular hairs (sometimes intergrading), rarely not armed. Lvs distributed along stems, usually imparipinnate, sometimes basal pair reduced to 1 leaflet, very rarely simple or reduced to connate leaflike stipules; leaflets serrate or crenate; stipules usually adnate to petiole with distal free auricles, sometimes free to base and deciduous, variously lobed or with marginal stalked glands. Fls usually borne on lateral shoots 1 or more years old, in corymbs, panicles or solitary, usually bracteate, usually > 3 cm diam., large and showy, ⚥ except in some semi- or fully double cvs, pedicellate, (4)-5-merous. Epicalyx 0. Hypanthium extremely variable, narrowly ovoid, narrowly urceolate, to globose, ± closed at apex by a disc; sepals all similar or outer 3 toothed or pinnately lobed and inner 2 entire. Petals 5, numerous in double-flowered cvs, those of single fls ± spreading, white, yellow, pink, red, purple, greenish or multicoloured, but not blue. Stamens numerous, fertile or petaloid. Ovary superior although carpels deeply sunken in the concave receptacle; carpels free, numerous; styles numerous, free or sometimes forming a short column protruding through the centre of the hypanthial disc; ovules 1 per carpel. Fr. an urceolate to globular or ovoid hip with many bony achenes included within the ± fleshy, coloured, sometimes prickly or bristly hypanthium.

c. 150 spp., mainly in temperate N. America and Eurasia, especially China, a few in subtropical S. and S.W. Asia, N. and N.E. Africa, and Mexico. Naturalised spp. 8 and 6 cultivated hybrids.

There has been a close association between members of this genus and human beings since early historical times, and through selection and breeding from wild and cultivated sources over the past 2 centuries, mainly in Europe, there is now a bewildering array of roses in cultivation. In spite of valiant attempts by rosarians this century, the taxonomic status of many hybrid groups, and even a few spp., remains uncertain.

Nearly all the cultivated roses are vegetatively propagated clones and have cv. names. Usually these names are in English, French or German, because the main selection and breeding has been carried out in W. Europe and the U.S.A. However, some roses were brought to Europe from China, Japan and the Middle East and only subsequently acquired a European name; in fact most of the cultivated spp. and hybrids of scrambling roses grown originate from E. Asia.

In N.Z., many roses were growing successfully by the end of the first 20 years of European settlement [ see, Steen, N., The Charm of Old Roses (1966)]. Now there are few private or public gardens without them, the majority belonging to hybrids of R. chinensis with other spp., (particularly the Asiatic R. gigantea Crépin). These hybrids have given rise to the erect, shrubby hybrid tea roses, a group which includes many of our modern double and semi-double flowered cvs such as the most famous clone `Peace'. It was the introduction of R. chinensis to Europe around 1800 and its subsequent hybridisation in the 1860's which transformed the cultivation of roses across the world, including N.Z., and displaced so many other roses. In addition to these shrub roses, the so-called climbing roses are nearly all sports from them and should not be confused with other roses which climb such as rambler roses. The derivatives from R. chinensis have contributed very little to the naturalised flora of N.Z.

The roses that were in N.Z. prior to the 1860's were mostly European spp. or hybrids derived from them and, apart from the brier roses, are often collectively termed old roses. The very vigorous climbing R. banksiae Aiton f., Banksian rose, is commonly cultivated and has been reported but not confirmed as wild. The yellow, double-flowered cv. 'Lutea' usually represents this sp. in N.Z. although the double white cv. 'Alba Plena' is also grown. Both cvs are unarmed, evergreen and have free deciduous stipules.

Sweet brier is the only sp. extensively naturalised in this country and it and the other spp. of sect. Caninae are the only ones described here which mainly or completely reproduce from seed. They were introduced deliberately although they are rarely cultivated now except as stocks for grafting other roses.

All the other roses mentioned here reproduce mainly or solely by suckers or layers, and are either erect shrubs or ramblers and other lianoid roses. Most of these roses are casual escapes from cultivation although some occur very frequently along roadsides in the neighbourhood of old dwelling sites, old mission stations and in and around old cemeteries. Doubtless a thorough search by a rosarian would reveal a few additional records of minor importance although Steen (op. cit.) travelled through N.Z. recording escapes from cultivation and subsequently growing them in her garden in Auckland. Most of the spp. or hybrid groups that she mentioned as being wild are treated here although a few of her records remain unconfirmed.

In this Flora, the taxonomy of the spp., hybrids and clones of the cultivated roses mainly follows Thomas, G. S., in Bean, W. J., Trees and Shrubs Hardy in the British Isles4 ed. 8 (Clarke, D. L., Ed., 1980). An alternative treatment is that by Krüssmann, G., Roses (1982), who gave a more horticultural system with less reference to the wild spp. However, the sectional classification used by most authorities is that of Rehder, A., Manual of Cultivated Trees and Shrubs Hardy in North America ed. 2 (1947). A synopsis of sections is not given here because so many cvs and hybrids have more than one section involved in their development.

Because of the complexity and uncertain origin of some of the hybrids, specimens of cvs not mentioned here, even if they belong to hybrid groups treated here, may not always key out easily.

In the following descriptions the leaflet measurements are taken from lvs in the middle and upper parts of the plant and often exclude the smaller basal pair of leaflets that occur in many roses, but include the usually larger terminal leaflet. There are several different types of prickles and hairs: large and usually stout prickles that most roses have on their stems; small but otherwise similar pricklets which often occur on lf rachises and infls; still smaller, thinner, straight acicles often present on stems, petioles and infls; stiff and rather long bristle-like setae sometimes present on many organs and which may be eglandular or glandular; smaller and usually dark red, glandular hairs which are often abundant, especially on young shoots, leaflet and stipule margins, hypanthium and calyx; simple, short, rather weak, eglandular hairs, often present on leaflet underfaces, petioles and stipules, and inside of sepals where they are often so dense as to form a tomentum. Unfortunately, N.Z. herbaria contain few specimens of the diagnostically important strong and often more prickly vegetative shoots of some taxa.

Flowering times given in the text do not attempt to cover minor, out of season bursts of fls, but do endeavour to differentiate between those taxa which flower for a short period only and those which have recurrent flowering as in the hybrid tea roses. The number of fls in an infl. can vary greatly in the rambler roses treated and the figures given do not always include the infls on small, lower lateral shoots, especially if these are in shade. Also, amongst the rambler and erect shrub roses with double fls, the petal measurement given does not include the smaller inner petals.

Fig. 100. Stipules, hips, and stems of Rosa sect. Caninae. A R. micrantha; B R. canina; C R. rubiginosa. © All rights reserved. [Image: 4X3D]

Fig. 101. Lvs and hips of Rosa. A R. pimpinellifolia; B-C R. rugosa. © All rights reserved. [Image: 4X3E]