In this post I have attempted to describe some of the evergreen shrubs and trees which are available for growing in our gardens. Apart from hedges (of Privet, Laurel, Holly and Yew), there are comparatively few evergreen shrubs grown. And fewer trees – there are not many of these however, to choose from (excluding the conifers); and none vies in beauty with any of the leaf-shedding, or deciduous kinds.
The shrubs are best for restricted spaces; and the smallest of the evergreen Rhododendron family perhaps the wisest choice for a good show. These plants, although lime-haters, can now be grown successfully in prepared beds of soil (made up of sifted peat or leaf-mould and sand), and in soil treated with lime-neutralizing agents obtainable from seedsmen and chemists. On the other hand, there are many evergreens which give a longer display of flowers and will thrive in any ordinary garden soil. And doubtless busy gardeners will consider these more suitable. For a labour-saving garden (which nowadays everybody wants), low-growing, compact shrubs, which cover the soil completely and prevent weeds from seeding and springing up, are ideal plants to grow.
Most of the plants are listed in current catalogues; and many large specimens for immediate effect are obtainable – these are more expensive of course than the small pot-grown plants which are normally sent out.
All gardeners like to experiment, but they don’t want to spend money on plants which may be too tender for their district, or require a special kind of soil, or some special situation.
There are some remarkably fine collections of evergreens in our old country gardens. One of the most famous is at Cliveden, near Taplow, Bucks. .
An evergreen retains its leaves all the year round. It is the reverse of the deciduous plant, which loses them in the autumn. Those gardeners who grow a variety of evergreens will have noticed however that some lose their leaves after a year or two. The Privet, for example, sheds them after a year; they fall in the summer as the new ones appear. There are evergreen Oaks which retain their leaves from 2 to 5 years, then shed them. And in the Pine family, the leaves (needle-like) of Pinus aristata and P. balfouriana, to mention only two, persist from 12 to 18 years. (Both species are natives of California.)
There are also semi-evergreens. These shed their leaves during exceptionally cold weather and when grown in unfavourable districts. Buddleia globosa , a native of Chile and Peru, often loses all its leaves in cold northern gardens. And B. officinalis, from China, prospers only in warm, southern countries and is then usually evergreen.
Eventually all kinds renew their leaves, some of the oldest falling each year, while new ones are produced at the tip of each branch.
The most magnificent, the most striking of all evergreen shrubs and trees are the broad-leaved kinds that grow in the tropics, especially in the vast rain forests, where the moist, festering leaf-soil and the atmospheric conditions are ideal. Their leaves grow to an enormous size – thick, leathery leaves, very different from those of the deciduous plants that grow in our temperate zone.
The ideal place for hardy large-leaved evergreens in cultivation is a region which has an equable climate and an abundance of moisture in the soil and the atmosphere. One thinks immediately of south-west Ireland and the south-west coast of Scotland; and in gardens in these regions one comes across the finest specimens.
In the cold bleak regions of the world, and in the arctic, evergreens are chiefly conifers (cone-bearing shrubs and trees), whose leaves are often needle-like or mere scales and thus have an exceedingly small surface to expose to cold, drying winds; the plants are therefore able to survive the worst frosts, winds and snow.
None of the big-leaved evergreens such as Rhododendron giganteum (from the high, open forests of S.W. Yunnan) flourishes in or around the Thames Valley, since in this district there are frequent droughts in summer and long, cold, wet, frosty spells in winter and early spring; these glorious exotic plants will grow only in protected gardens in places like Cornwall and Devon. Even some of the conifers (the Christmas Tree, Picea abies is one) seldom thrive in many of our dry, inland gardens; they can tolerate the cold and frost; but frequent dryness at the roots causes the trees to grow weak and feeble. The finest, strongest specimens, with good thick branches, come from those regions where the rainfall is highest.
To grow evergreens successfully, especially the best of the ornamental flowering kinds, it is essential to have the right soil for them, and for the choicest a position sheltered from cold winds and frosts. One can do nothing about atmospheric conditions – one can only spray and water the large-leaved Rhododendrons and Camellias which often need it; but if one lives in a hilly, exposed district, where the soil is starved and thin, it is best not to attempt to grow the rarer kinds at all.
Gardeners who will be most successful are those who live in warm, maritime districts in the south and south-west of these islands. And fortunate indeed are those who garden in the moist, lush valleys of south-west Ireland; for there they can grow many of the large-leaved Rhododendrons and even the fragrant Mimosa – shrubs which in most parts of England are seldom seen outside the greenhouse.
But there is a vast number of hardier things which thrive in practically every garden – after all, many fine specimens of hybrid Camellias grow outside at Kew Botanical Gardens; many lovely Heathers prosper in gardens around London; and the red-flowered winter varieties, well grown and flourishing, are worth any number of rarer evergreens languishing in gardens where they obviously should never have been planted. It is always wise before ordering any rare shrubs or trees to find out which kinds are best suited to the district where they are to be grown. Nurseries are glad to advise their customers on matters of cultivation and maintenance.
The modern garden on the whole is small and could not accommodate any of the biggest evergreens such as some of the old hardy hybrid Rhododendrons or, say, a fully-grown Silver Fir or a Blue Cedar, shrubs and trees common enough in the large pleasure-gardens of the past. But there are plenty of smaller kinds suitable for limited spaces. There are, for example, the evergreen Japanese Rhododendrons (better known as Azaleas), and many dwarf Conifers which are often grown in rock-gardens. In fact there is now an extraordinary wide variety of small compact evergreens available. New hybrid Heathers and enough of them to provide patches of brilliant colour all through the year and, moreover, Heathers which don’t mind ordinary garden soils – as is well known, the vast majority in their natural habitats flourish only in peaty, lime-free ground.
Most of the low-growing compact evergreens may be described as labour-saving plants, since they grow close to the ground and thus prevent weeds seeding there and shooting up. Nothing could be more acceptable to the busy modern gardener.
What there is a shortage of are hardy evergreen climbers. In my opinion our native Ivy is a beautiful and very useful plant; its use in the garden is decried however by many people probably because of the plant’s invasive character and its insidious habit of covering everything near it. I think it is charming on walls; incidentally it makes a fine dark background for many flowering shrubs; and the variegated and the large-leaved kinds are delightful for covering bare ground under trees. The Ivy is perhaps the only truly hardy evergreen climber we grow. I have the so-called Japanese Honeysuckle (Lonicera japonica) growing among shrubs in my garden, where it proves to be evergreen, and it carries its deliciously fragrant flowers over an exceptionally long period. I have had it in bloom as late as November.
But these two climbers don’t appeal to everybody. After all, there are plenty of deciduous kinds which are far more beautiful.
And of all the evergreen plants we can grow in our gardens, very few approach the hybrid Rhododendrons in floral beauty and usefulness. The busy man who can spend only a short time gardening will doubtless make them his first choice.