Island Beds can not only be seen from all sides, but access to them for such necessary maintenance tasks as hoeing or weeding is much easier than with the old conventional border style. With light and air plants grow to the height nature intended and no more. This brings them into the most effectivefrom the point of view and creates fewer problems when some kinds need replanting, as some do every few years, to keep them vigorous and free flowering. All,this however depends on one other important factor—that of spacing and the preference it suggests of growing different kinds in . So often the effect is spoiled by dotting a plant here and there indiscriminately even to the extent of duplication.
Common sense planning.
Naturally an Island Bed should have its tallest growing subjects near the centre, whereas of course in a one-sided border they must be placed at the rear. This grading of heights is purely for effect, so that each kind can be seen and appreciated. Given adequate width this is easy to arrange so long as one remembers or knows the height to which each kind can be expected to grow.
Such details are included in the description of each kind illustrated, and most specialists catalogues provide them. In selecting a variety restrict the height according to the width of the border. The narrower it is, the shorter should.be the tallest kinds chosen. A useful rule to follow is to divide by two the width of the border, in feet, and to keep within the limit this gives in regard to height. A border of any type, of say 8 feet wide, should contain nothing taller than about four feet. Narrow beds or borders and excessively tall plants simply do not make sense. But they make for trouble and loss in terms of effectiveness of display.
It can be assumed that a reader wishing to go in for perennials will chose one or more of three courses. A new garden will call for a decision as to where a bed or border should be. The site may be clear for an Island Bed, and it would be a commendable decision to use a plot nearer the centre, rather than a strip along the boundary. The latter would be much better as a screening border for shrubs, interplanted with ground coverers, leaving the centre for both lawn and an Island Bed if the latter appeals. It need not of course, occupy the exact centre. Most garden plots are oblong, and an Island Bed could well be placed towards one end, as a breaksay, between the kitchen and ornamental sections. In such a case, viewed as it would be mainly from the house, the grading of heights should be more gradual from this aspect than from the rear.
At the back some access should be given by a path, however narrow, and beside this could be plantedof early flowering perennials such as Primroses, Pulmonarias, etc. These would be over by the time the summer perennials grew tall enough to hide them.
This design could be termed as a semi-island bed, distinct from the true type, which aims to have a more or less even grading of heights from every angle, as one walks around its perimeter. Bearing in mind the need to restrict heights when making a selection according to the width of the bed, with the tallest in the centre part, the effect is very pleasing. One should also try to intersperse kinds having differing habits of growth, so as to break up any tendency to flatness or regimentation. Some kinds, especially those of the Daisy family havemore or less on one level. Others are spikey in growth—like and Kniphofias. It is by planting the latter in groups amongst the former that the best possible effect is achieved—with an eye to continuity as well.
Spacing for effect.
Spacing, as will be seen, is also important. Assuming groups of three or more plants are used of one kind, rather more space should be allowed around each group than between each plant comprising the group. The average planting space is 16’-18’ from plant to plant, but between groups it should be20’-22’.
The more robust growing kinds would of course need wider spacing, but for dwarfer, slower growing subjects it can be less.
It follows too, that if a vigorous, tall or very robust kind is planted next to another with much slower or lowly growth the latter will suffer after the first season or two. Segregation is easy to practice. It means simply, that in selecting and placing, growth rate as well as height should be taken into account, so as to keep the vigorous kinds more or less together in one part of the bed or border and the slow spreaders in another. Mention of this should not however, be taken as a deterrent to readers. None of the subjects mentioned are of weedy nature, and those that are merely vigorous can easily be curbed should their spread become excessive.
Continuity and display.
Continuity is also a matter of making a right selection. Not many kinds flower before May, and the peak period for Hardy Perennials is from mid June to late August. There exists sufficient variety to have the maximum display in spring, summer or autumn, but most people prefer to have them cover as long a period as possible. This may mean placing more than ordinary emphasis on the very early and very late flowering kinds if fairly regular continuity is to be achieved. In my own garden, where a very wide variety exists, the firstappear in February, and in mild winters, there are still flowers to be seen the following Christmas. A careful selection can also achieve a predominance of favourite colours or colour combinations. Sufficient variety exists to do this, as well as to use the many grey, silvery and variegated foliage plants if any of these hold a special appeal.