No single word or term has yet been accepted to cover garden plants, as distinct from bulbs and shrubs, which flower year after year.
‘Herbaceous plants’, ‘hardy perennials’, ‘border plants’ are all inadequate or inaccurate in some respect. Strictly speaking, the word ‘herbaceous’ denotes the decay of each season’s growth, with the plant itself remaining alive, but dormant., phlox and many others have this habit but several, including iris and kniphofia do not, because they retain winter foliage.
The time is happily past when hardy perennials were relegated in so many gardens because the rewards they gave were disproportionate to the trouble entailed. One reason was because post-war demands for labour saving forced a swing to shrubs. The conventional herbaceous border was largely at fault because of its long narrow shape with a backing wall, hedge or fence. The plants suffered from overcrowding, weak growth and excessive competition for light and air. Quite often such borders were too narrow in relation to the height of the plants. All this accentuated the main disabilities to which perennials are prone if not given a fair chance difficulty of access to the plants and the need or supports. Harmful competition between the ranker and the less vigorous kinds, and indiscriminate selection and planting almost invariably lead to trouble.
This calls for a fair-minded approach when one considers that nature herself has set the limitations. The majority of garden plants have their origin somewhere in the wild. An original type may have been improved upon by breeding and hybridization, but the varieties or cultivars retain their main parental characteristics, including those of adaptability. A species which for millions of years has been accustomed to certain conditions of soil, moisture, sun or shade can scarcely be expected to flourish so well where its natural preferences are lacking.
Most perennials are adaptable to ordinary garden conditions, but it would be as much a mistake to plant something which naturally prefers shade or moist soil into a dry open situation as it would the other way round. It would also be a mistake to plant something rank or invasive near something that is by nature of slow or lowly growth.
Light and Air
The problem of overcrowding is linked to this. Plants need light and air and overcrowding and overhanging by trees or other taller growth, which reduce these inevitably leads toweakness. Plants in close competition for light and air become excessively tall and spindly. It is a vicious circle and is the major cause of untidiness and the need for staking in congested borders, or those backed by tall trees, shrubs, hedges, fences or walls. Usually where staking is necessary, it is not the fault of the plants but of the conditions under which they are grown.
Some years ago people started experimenting with ‘island beds’ and showed that not only were the plants shown to greater advantage, with all-round access, but very few needed staking, whereas the great majority had needed supports in the conventional one-sided borders. Although first-year growth was shorter, in succeeding years the growth was just as sturdy, with only such heavy spiked or headed plants as delphiniums and tall Michaelmas daisies needed support. Since then Mr Bloom has constantly advocated island beds as the best means of growing perennials. In the process, he has grown thousands of species and varieties.
However, the small rectangular plot which most people have, with similaron either side, rules out the informality of island beds and such gardens admit of little choice but to go in for flanking borders. Even so in a small or otherwise inhospitable site, there are still ways and means of growing perennials successfully.
The main thing is to select plants best suited to the place in which they are to grow. The range of available plants is sufficiently wide for this to be achieved, no matter how small the garden, or unkind the soil, so long as it is not completely hemmed in by tall buildings or overhung by large trees to exclude both light and air, and to compete for the available food and water. Even the conventional one-sided border with a high backing can be improved by growing kinds most suitable or adaptable to it. Such borders are usually far too narrow in relation to the height of the plants. Some plants are often invasive and attempts to grow shorter, choicer kinds as well have failed because of unfair competition. What is needed is a new approach, a new appreciation of garden worthiness and adaptability.
The range should include certainor corms, such as crocosmia, which contribute greatly to the summer , also certain dwarf perennials. If they are adaptable for growing in front of taller kinds, in ordinary soil conditions, then there are very good reasons for including them. Plants of, say, 6 to 12 in. tall are by no means out of place as frontal and in small gardens where beds have to be small, then dwarf plants are both desirable and necessary.