The Cultivation of New Zealand Plants
The shrubby veronicas are a specially remarkable feature of our flora. They are likewise garden plants of the highest value by reason of their many distinct forms, wealth of blossom, and ease of cultivation and of propagation. They vary from a forest-tree with a distinct trunk (V. gigantea), see fig. 3, to a tiny herb (V. canescens), by way of shrubs large and small, erect or prostrate, green-leaved, or glaucous, or those which mimic the cypress.
As wild plants they grow on the sea-coast, in forests and shrubland, on dry or wet rocks, in swamps and bogs, on barren moorland, in the tussock-grasslands, and ascend to the snow-line, forming mossy cushions on the great screes of the Southern Alps, or the scoria of the volcanoes. In the garden there is no place, page 63except the most shady, where one or other of the species will not thrive. The smaller whipcord, and prostrate glaucous veronicas, are admirable for the alpine-garden, while the taller will adorn border, or shrubbery, and some make excellent hedges (see fig. 4). Their propagation is simple: all strike rapidly from cuttings when placed in the open in slight shade; seed germinates well. Cuttings, if taken from branchlets, which have flowered, may bloom the following year. Such small plants can be used in the alpine-garden and removed when too large. Nearly all the species bear severe trimming, and if becoming leggy it is necessary.
More than 100 species are recognized by botanists, and there are also many wild hybrids. Thus, there is intense variation, so that the classification of Veronica is an extremely difficult matter, and their recognition in the field, or in gardens, far from easy.
At the present time our veronicas are more prized than ever before, owing largely to their intrinsic value, and the increasing desire for native plants; but, in some degree, to the influence of the great collection brought together at Weatherstones, Otago, by Messrs. Hart and Darton.
A certain number of hybrids have been raised, especially in the Royal Botanic Garden of Edinburgh. Much more could be done in this regard, and it seems reasonable to expect that, some day the crimson of V. speciosa, the lovely blue of V. Benthami, and the lavender sprays of V. Hulkeana may be associated with the ball-like, the cupressoid, or the creeping glaucous forms.
Here, the name "Veronica" is still used, but the time is not far distant when, for the shrubby section it will be replaced by the more correct name, "Hebe," for there are important distinctions between the above page 64and Veronica proper. Hebe, thus limited, is a subantarctic genus with its headquarters, and the bulk of its army, in New Zealand, but with isolated, small outposts in South-eastern Australia, Tasmania, Fuegia, and the Falklands. Nevertheless those species allied to V. Lyallii will still be veronicas, while the moss-like alpine herbs will receive again their original name, "Pygmaea."