New Zealand Plants and their Story
Chapter XIII. — The Cultivation of the Plants
The Cultivation of the Plants.
Indigenous plants suitable for school-grounds—Difficulty of growing native plants much exaggerated—Methods of collecting and propagating—Plants suitable for growing from cuttings or from seeds—The school-garden—List of native plants suitable for schools—Cultivation of alpine plants—List of easily grown alpines.
That the plants of New Zealand afford rich material of a most varied kind for nature-study in our schools should be fairly manifest to readers of the previous chapters. Many facts, of course, can be best learnt in the field; but most of the centres of population are far from the virgin vegetation, while the plants of the neighbourhood will generally be interlopers from abroad. In order, therefore, to become really familiar with the indigenous plants, and to watch them at various stages of growth and at all seasons, they must be cultivated; and almost every school in the Dominion might have, at any rate, one bed, even if quite a small one, of the native plants. The gums, oaks, "macrocarpas," and other foreign trees now grown for shade or ornament in the school-grounds may be seen everywhere, and each school throughout the land might gradually replace or supplement them by those New Zealand trees best suited to the particular locality. Thus would the schools as a whole become sanctuaries where the native plants, one of the peculiar features and special glories of the land, would be safe for all time.
But it may be urged that such planting would not be feasible, since every one knows "the native plants are particularly difficult to grow, and when removed from their home in the forests or elsewhere will die." Such an opinion, although widespread, is quite erroneous. It is the rough treatment so frequently accorded to the specimens, first on their being collected, and afterwards when planted, that causes failure, and not any special difficulty in their cultivation; indeed, many are quite as easy to grow as the rank and file of garden plants.
There is no reason why, for instance, the kowhai, manuka, lace-bark, ribbonwood, lancewood, totara, large clematis, Goprosma robusta, page 168kauri, pittosporums, and various other forest-plants, as well as almost all the members of the subalpine scrub, should not be cultivated almost anywhere. The mistake so frequently made is to attempt the impossible—i.e., trying to grow a plant in a climate quite unsuitable. It is unreasonable, for example, to expect that the majority of lowland North Island trees can be grown in Canterbury, Otago, and Southland, just as it is hardly wise to try to cultivate plants of alpine and subantarctic meadows in the hottest or driest localities.
For the successful cultivation of many of our plants no particular soil or situation is required. Perhaps, on the whole, a slightly shady position is best. It is well, too, to have some shelter against high winds, especially at first. Such shelter can be supplied by certain indigenous trees—e.g., species of Pittosporum, Olearia Traversii, Senecio rotundifolius, Coprosma Baueri (not hardy everywhere), Coprosma robusta, and Veronica elliptica. Of course, an accurate knowledge as to the situation in which a plant grows naturally is of extreme value, and the method of studying the plant societies adopted in this book is of moment in this respect. But this is not all. It must have been seen by the reader that one particular species may grow in most diverse stations, and that another may grow in a wet place which is physiologically dry. For instance, because a plant grows in a sphagnum bog, it would not necessarily be wise to plant it in a very wet part of a garden. To attempt to grow the lovely Olearia semidentata of the Chathams in such a place would be to court disaster; it must be grown in well-drained ground where there is good shelter. Nor because the great forget-me-not of the same group is a sea-shore plant need one despair to cultivate it inland. In short, an acquaintance with natural conditions combined with experimental planting is a necessity for a full knowledge as to the cultural requirements of our plants.
Methods of Propagation and Collecting.
Quite a number of New Zealand plants can now be procured cheaply at some of the nurseries, and from such many will obtain what they may require. However, there will always be some who prefer to collect what takes their fancy in the forest, on the hillsides, or elsewhere. This, as well as being a healthy and delightful occupation, will stock a garden with mementos of many a happy hour, and will recall scenes of beauty.page 169
As to the digging-implement, something light, strong, and easily carried is required. For many years the writer has used a shingling-hammer with the head beaten out into a small pick-axe, a tool first designed by the late Mr. H. J. Matthews. By means of this the strong-rooted plants of an alpine meadow may be attacked, large stones cleared away, and so on. Within the forest, small seedling trees and shrubs are in plenty. But, rather than secure those of the forest-shade, procure those of the outskirts, which are exposed to more sun and wind; and in such a situation the majority of the forest trees and shrubs, from the lordly kauri to the wiry-twigged coprosmas, may be found, while the smaller the plants are the better. These, when dug up, should be quite freed from soil, nothing being gained by taking up great pieces of earth. The roots should next be closely wrapped round with wet moss, using bog-moss for preference. Alpine plants, too, can be mossed similarly. Finally, to save room and conserve moisture, a number of such plants can be tied into one bundle, the mossed roots being all together. It is astonishing how long plants will remain in good condition if treated in this manner.
These collected plants, upon being brought home, should be planted in boxes or potted, or put into nursery-beds in a shady part of the garden. Of course, if there is a greenhouse, frame, or, better still, a shade-house or plant-protector fitted with a blind, into one or other of these the boxes or pots should go. Some species, difficult to grow from seed or to strike from cuttings, are best collected in their habitats —e.g., many alpine herbaceous plants and subshrubs, various species of Dracophyllum, orchids of all kinds, Gunnera, Dacrydium laxifolium, the various beeches, and the species of Gaultheria. Cuttings in many instances will serve as well as if not better than young plants. The following may be propagated in this manner: Veronica, Olearia, Senecio, Cassinia, Aristotelia, Myrtus, Griselinia, Rubus, Podocarpus totara, P. nivalis, Gaya. Cuttings are best taken in the autumn, and should be struck in coarse sand in a shady place. If placed in pots or pans, those pieces pressed against the edge of the pot have the best chance. They can be struck also in a shady, some even in quite a sunny place in the open. The ground should be kept damp, but not sodden with water.
Most New Zealand plants suitable for gardens can be raised from seed. This should be as fresh as possible. Species of the following page 170genera usually germinate with great ease: Sophora, Carmichaelia, Veronica, Epilobium, Pittosporum, Melicytus, Pennantia, Hoheria, Celmisia, Hymenanthera, Gaya, Plagianthus, Fuchsia, Muehlenbeckia, Calystegia, Notospartium, Acaena, Rubus, Clematis, Leptospermum, and Coprosma. Small seeds should be covered with very little soil. Seeds are much better sown in boxes or pots than in the soil of the open border. The soil in which they are sown should consist of 50 per cent. or more of coarse sand.
So far as a school-garden is concerned, it is quite out of the question to draw up any general scheme. Everything depends upon the situation of the school, the enthusiasm of the master, and, above all, on the interest of the scholars. Perhaps one rather narrow bed alongside a fence, and out of the way of damage during the play-hour, would in many instances meet the case. In other places certain corners here and there would possess special advantages. The ground should be dug deeply and the drainage be good. Every plant should be labelled distinctly but not obtrusively. As well as the name, the place where the plant was collected should be noted. Labels may be made of some durable wood (totara, for instance), zinc,* or iron. As fox the plants to be cultivated, that also will depend upon teachers and pupils. At any rate, it is better to grow a few well than to have many neglected.
The following plants are easy of cultivation and not difficult to procure:—
Trees.—Sophora grandiflora, S. microphylla (kowhai); Plagianthus betulinus (ribbonwood); Gaya Lyallii, G. ribifolia (mountain-ribbon-wood); Hoheria (any of the species), (lacebark); Griselinia littoralis (broadleaf), G. lucida, where hardy; Pseudopanax crassifolium, P. chathamica (lancewood); Phyllocladus trichomanoides (tanekaha, celery-top pine); Nothopanax arboreum (ivy-tree); Meryta Sinclairii (puka), where hardy; Metrosideros tomentosa (pohutukawa), where hardy; Agathis australis (kauri); Corynocarpus laevigata (karaka), where hardy; Vitex lucens (puriri), where hardy; Pennantia corymbosa (kaikomako); Pittosporum Ralphii, P. eugenioides (tarata), P. tenuifolium (tawhiri), P. crassifolium; Brachyglottis repanda (rangiora), where hardy; Phebalium nudum; Leptospermum ericoides (tree-manuka); Myoporum laetum (ngaio), where hardy; Olearia Traversii page 171(Chatham Island akeake); Cordyline australis (palm-lily); Nothofagus fusca, N. cliff ortioides, N. Solandri (native beeches).
Shrubs.—A selection of distinct veronicas—e.g., V. Traversii, V. Dieffenbachii, V. buxifolia, V. elliptica, V. anomala, V. cupressoides, V. Lavaudiana, V. Hulkeana, V. pinguifolia, V. Hectori, V. salicifolia, V. macrocarpa, V. diosmaefolia, V. chathamica, V. decumbens. Any of the taller-growing veronicas, if they become too big, can be cut out altogether and replaced by young plants grown from cuttings. There should be a selection of olearias—e.g., O. nitida, O. avicenniaefolia, O. virgata, O. ilicifolia, O. Solandri; in fact, almost any can easily be grown except O. semidentata, O. angustifolia, and others of that class, and even these grow well in south Otago, Westland, and Southland. Most senecios are easy to cultivate, and are very showy when in full bloom—e.g., S. compactus, S. perdicioides, S. Greyii, S. laxifolius, S. Monroi. Other shrubs easy of cultivation are the carmichaelias (native brooms), Notospartium Carmichaeliae (pink broom), the cassinias, many of the coprosmas, Melicope simplex, Myrtus bullata, M. obcordata, M. pedunculata.
Lianes.—The various species of Rubus are interesting plants. R. australis, with its great mass of white blossoms, is handsome when in bloom; R. schmidelioides goes through a juvenile and adult form, the former having much thinner leaves, and occurring usually on the forest-floor; and R. cissoides var. pauperatus makes a pretty bush, partly owing to its yellow prickles, and has a very curious appearance, with its leaves reduced to midribs. Then there is Senecio sciadophilus (the climbing-groundsel), and the various species of clematis.
Ferns.—Here, again, it all depends upon the climate of the proposed garden. In many parts of the North Island (the Manawatu, Taranaki, and parts of Auckland), tree-ferns, especially the black tree-fern (Cyathea medullaris), thrive splendidly in the open, and a grove of these may be made a striking feature. But in many districts the most shaded positions alone must be chosen, or even a special structure would need building for the ferns to thrive. The following are some of the most easily grown species: Cyathea medullaris, C. dealbata (silver tree-fern), Dicksonia squarrosa, D. fibrosa, Asplenium bulbiferum, A. lucidum, Polystichum vestitum, P. Richardi, Adiantum affine, Hypolepis tenuifolium, Pteris incisa, P. scaberula, Blechnum fluviatile, B. capense, B. discolor, Polypodium pennigerum, P. Billardieri, P. serpens, Nephrodium hispidum, Pellaea rotundifolia.
* Zinc labels can be easily written upon, using as ink a solution of sulphate of copper.
Perhaps a formal rockery, or a special alpine garden, may seem altogether too ambitious for a school-garden. Still, the New Zealand mountain-plants yield such instructive material for study, and are so beautiful or curious, that a few, at any rate, should be grown; and there is usually some shady corner that might be spared for these plants. Also, a good deal can be done in the way of providing a suitable growing-place by the aid of a few bricks or stones, especially if there be an abundant water-supply.
Of all forms of flower-gardening, this growing of alpine plants is the most fascinating. During recent years the alpine garden has become firmly established in Europe as an indispensable part of any garden of note. In scientific establishments, too, the cultivation of alpine plants is pursued with vigour. The new Botanic Gardens of Berlin have a great rockery, arranged on plant-geographical principles, to represent the different alpine floras of Europe. Some day, when we in New Zealand have what we ought to possess, a national botanic garden, it may there be possible to reproduce the different plant societies of New Zealand. The Royal Botanic Gardens of Edinburgh have the finest collection of alpine plants in Britain, and are specially rich in New Zealand species. Many of the Continental universities have their alpine gardens high in the Alps, where the effect of an alpine climate on the form and structure of plants can be studied.*
Fig. 68.—Alpine Vegetation of Tongariro. Gentiana bellidifolia in bloom. A natural Rock-garden.
Lands Department.] [Photo, L. Cockayne.
Any of the taller subalpine scrub plants can be used, and can be replaced by smaller specimens when they get too big. In fact, the plants to be made use of will depend so much on the size and situation of the alpine garden that hints regarding what to grow are not of much use. Moreover, the enthusiastic collector will bring home all sorts of plants, regardless of their capabilities, and the success of the alpine garden will be due entirely to his own energy, and to the knowledge he will acquire in the school of experience.