Hillside Gardening Plants for a bank or the hill side.
The simplest way to plant a bank is to make a grassy slope of it. This isn't the best way in which a bank can be treated, since it lacks interest and will be more difficult to mow than a level lawn.
If the bank is fairly extensive an excellent way to cover the soil is to plant some of the many fine climbing and rambler roses. The long shoots are secured to strong wooden pegs and stride across the ground in a series of low arches. It is surprising how this treatment causes the whole plant to flower most generously.
A treatment suited to a sunny aspect is to plant the bank with a variety of low growing flowering shrubs to produce a kind of `maquis'. Suitable shrubs for this purpose would include: rock roses such as Cistus cyprius and C. laurifolius, the prostrate cotoneasters, lavenders, genistas, halimiums, helianthemums, hypericums, Phlomis fruticosa, rosemary, the red-leaved sage (Salvia officinalis rubrifolia), Berberis thunbergii atropurpurea, rutas, several artemisias and santolinas, and the Scotch brier roses, which are, unlike most roses, completely trouble free. The Scotch briers have been developed from the native burnet rose Rosa spinosissima. They have a fair range of color and they increase slowly and steadily by suckering. Even in winter their close sheafs of branches make an effective note of warm brown color. The chief disadvantage of these briers is that they are somewhat rare now. The search for these precious shrubs is itself an adventure, but several specialist rose growers offer a small selection.
If there is a path which dips between banks, the feature is, in effect a 'dell' and here, if the soil permits it, there is a splendid opportunity to plant rhododendrons in a way which seems to set them off to the greatest advantage.
On the same banks of acid soil as the rhododendrons enjoy the dell might more modestly be a heather dell, and this could give color the whole year through, for even in the coldest winter weather there are masses of bright heather blossoms cheerfully glowing. And soil is less important where the winter-flowering heaths are concerned, for Erica carnea and its numerous cultivars, which flower from November to April, will succeed on chalky soils.
It is possible, also, to make rough terraces and these may be planted up with the more amenable rock plants. In fact this treatment reaches a stage when it might well be regarded simply as a rock garden (see Rock gardening, Rock garden plants).
Terracing the bank in this way can give it a somewhat exotic look if the top of the bank has one or two of the large noble-looking but perfectly hardy yuccas placed so that they can be seen against the sky. When they bloom the effect is superb. Either Yucca gloriosa or Y. recurva will give this effect, and the much smaller Y. flaccida will give an annual show of its white lily blooms. A list of plants suited to the terraced bank would include : wallflowers, snapdragons, thrift, rock pinks, iberis, aubrieta, alyssum, arabis, Campanula garganica, C. portenschlagiana, the mossy saxifrages, dianthus, Genista lydia, Phlox subulata, and many others.
As can be well seen from a railway carriage window, many flowering plants are capable of taking care of even the most difficult conditions provided by the steep banks of raw earth which often border the permanent way. Here may be seen Hypericum calycinum, the rose of sharon ; the periwinkles, Vinca minor and Vinca major; and particularly on raw chalk, the red valerian, Centranthus ruber ; with an occasional taller note provided by that easy going shrub the bladder senna, Colutea arborescens.