In planting both walls and pergolas there is danger in planting too thickly, and in planting too hurriedly or without sufficient preparation. We all must perforce often do the best we can rather than the best we know. Large-growing, permanent shrubs, such as Pyrus japonica, Wistaria, and Magnolias, which may remain in the same spot for twenty years or more, often fail through starvation, and in any case never attain their full luxuriance and beauty if cramped and stunted during the first few years after planting. Again, it must be remembered that both wall and pergola creepers often suffer from dryness during the summer and autumn months, and provision should be made for necessary mulching and watering.
There is one important point that must be attended to in the planting of anything of which the general hardiness is not fully assured, and that is, never plant late in autumn. The golden rule with all half-hardy things is to plant well in April or May, after all danger from severe frost, &c., is over, so as to allow the plants a long summer and autumn season of root and top-growth before the stress and strain of winter weather come upon them. In this way many plants will succeed perfectly in establishing themselves that would at once die off if planted out in October or November.
Abelia.—A. floribunda is a Mexican plant. Mr. Burbidge writes in the Garden, April 14, 1900, p. 272: "I have seen it very handsome in flower on a low wall at Mount Usher, county Wicklow. Its pendent flowers in axillary clusters are of a rich purple red, and remind one of some Fuchsias." A. chinensis, a Chinese plant, is very pretty, as also is A. triflora from North India.
Abutilon.—Several of the Abutilons are sufficiently hardy to thrive on walls or in borders near to heated plant-houses. Mr. Burbidge writes in the Garden: "I have seen A. striatum, A. vexillarium, and A. vitifolium grow and bloom for years outside. The last-named forms a spreading bush 10 to 13 feet high in South, West, and Eastern Ireland. It has leaves somewhat resembling those of the Grape Vine, and clusters of pale-lilac, mauve, or lavender-tinted flowers that remind one of those of Meconopsis Wallichi in shape, size, and colour. A. vitifolium comes from Chili, and enjoys shelter and ample root moisture, being apt to suffer from drought near walls, otherwise it grows well thereon." Abutilon vexillarium, when afforded the protection of a south wall, blooms for eight months out of the twelve, bearing on slender, curving shoots its handsome, bell-shaped flowers with their crimson sepals, yellow petals, and protruding dark-brown stamens well into the month of December should no severe frost occur. Florists' varieties of the Abutilon, such as Boule de Neige, also do well on sheltered walls.
Adlumia cirrhosa.—This grows quickly, and the fern-like leaves, covering almost the twining stems, possess much beauty; the flowers are white. A biennial, but sows itself freely. North America.
Akebia quinata.—A most distinct Japanese creeper with five-lobed leaves and twining stems; although generally grown in a greenhouse, where it flowers in January or February, it is quite hardy in mild sea-shore places, and bears its monœcious flowers in April or May. The rich wine-purple flowers are borne in axillary grape-like clusters, and their translucent petals are very beautiful as seen between the eye and the light. It likes a rich, deep, loamy soil, and is increased by suckers or layers. Although introduced to our gardens from Chusan in 1845, it has never become very abundant, but it deserves a place for its distinctive character.
Aloysia citriodora (Sweet Verbena).—Another popular name for the Aloysia is Lemon plant; it is a fragrant pale-green leaved bush, not very hardy, and therefore best placed when against a sunny wall. Except in quite the south of England and Ireland, it is generally wise to cover over the stems with a straw mat and heap ashes over the roots. It is often seen as a large bush against the sea. We have seen it thus on the Carnarvon coast. Chili.
Ampelopsis.—Now included with the Vines (Vitis).
Apios tuberosa.—This has pea-shaped violet-scented flowers. It is sometimes pretty rambling over a shrub. North America.
Aristolochia Sipho (Dutchman's Pipe).—Frequently planted against a wall; its leaves are very large and handsome, and the dull-coloured flowers, owing to their shape, have given rise to the popular name.