Plants For The Flower Garden

Trees and shrubs for structure

A number of shapely evergreen shrubs provide the border with winter structure and, planted at regular intervals to give a definite rhythm, hold the border design together throughout the year. Their shapes and foliage contribute more than their flowers, and they set off the flowers of neighboring plants. Conifers such as tall junipers, feathery chamaecyparis, Irish yews and, in milder areas, Italian fastigiate cypresses all give this emphasis.

Some shrubs may be pruned into topiary shapes and figures to give a more formal air to a planting scheme. Traditional topiary subjects are evergreen bay, holly, Portugal laurel and yew (both English and Irish at Hidcote trimmed English yews give border structure in the famous Pillar Garden). The neglected phillyrea (especially Phillyrea angustifolia and the tree-like P. latifolia), pyracantha, Quercus ilex and box may also be trimmed into many different outlines. Silver- and grey- leaved shrubs may acquire a formal air by tight clipping — indeed many that grow woody with age benefit from a spring cutting.

Small deciduous trees with green or colored leaves and a naturally regular outline are also effective design plants. Mop-headed and umbrella-shaped trees are especially useful when space is limited as neighboring plants can be grown up close to the trunk. Robinias. 

PLANT BREEDING AND SELECTION

Surprisingly few of the palette of plants available in nurseries and garden centre are original species. Most have been 'improved' by special breeding programmes in search of more desirable and robust qualities in flower, leaf or form. Sometimes these changes are just to obtain shorter or longer flower-stems, but all are aimed at enhancing the gardening possibilities. This breeding for improvement is a sexual process, not a vegetative one whereby cuttings are taken or grafts made to reproduce a particular plant such as one that has attractive gold and silver foliage.. To be certain of obtaining the same'freak' appearance, it is not possible to use a sexual process.

In breeding, the main objective is to exaggerate features considered useful or decorative and to lose others less obviously desirable. The results of breeding and hybridizing are complicated. In the past breeders would spend years looking for one desirable seedling that demonstrated a noticeable improvement in quality. Today, in theory, the selector or hybridizer chooses two good wild or garden forms (species or cultivars) of a genus and breeds from them, deliberately hoping to produce a strain that inherits the best characteristics of both 'parents'. Of course it may still take time to find the desired combinations, and breeding is aimed not only at producing plants that look good but also at producing those that are disease-resistant, have extra hatdiness or some such other more 'hidden' qualities. For final marketing of new hybrids a crucial discovery has been made: that first generation hybrids (called F1 hybrids on the nurseryman's seed packet) are both uniformly reliable and possess the benefit of hybrid vigour. Such a discovery has transformed the horticultural trade and means that, once a strain is chosen, garden perennials and annuals may be produced by annual cross-breeding from two chosen parents. An additional marketing 'plus' is that the amateur does not find the same uniformity in saved seed but has to buy fresh F1 hybrid seed each year.

Sometimes scientific breeding alters an harmonious natural balance, and highly bred 'improved' plants, selected for certain exaggerated characteristics such as flowering potential, lack the simple grace of their wild parents. Personally the more I garden, the more I prefer the elegant natural proportions of true species, even though I know that their performance is muted. With trees and shrubs such reticence would cause no problem, but in the flower garden my choice of perennials and annuals wood be more limited and less satisfactory without 'improved' plants. However I do think it would be interesting to lay out a whole scheme using true species alone. I would certainly do this if I had a woodland garden in parts of the United States, where nature's 'produce' can hardly be bettered. But in general we use and are grateful for the thousand and one 'possibilities' provided by the dedicated breeders; from amongst their products we can choose plants exactly suited to any garden scheme. In 'natural'-type gardening, true species often look appropriate; in the formal border we need plants that give precise effects, and those specially bred for longer flowering periods.