Regional Gardening Reports :: National Gardening Association

In the Garden:
Coastal and Tropical South
February, 2012
Regional Report

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Classic nandina has spawned cultivars with the unusual combination of strong color and fine texture.

Choose New and Old Plants

The world is full of plants to grow, some ancient and some quite new. The classics and newer releases deserve equal attention for space in your garden.

Whither New Plants
There are two basic ways that new plants are developed from venerable parents, selection and breeding. When large groups of one plant species grow in the same bed or field, their natural differences emerge. One might be taller than average, have narrower or more colorful leaves, or bigger flowers that rebloom. A grower takes note and propagates the unusual ones for many generations to determine if the diversion is stable and so can be considered a different plant. Such discoveries are known as cultivars and are given names that reflect their selection from a species, such as Camellia japonica 'Debutante'.

Plant breeders look for ways to create new plants from existing ones by crossing, say, a vigorous tomato with one that tastes especially sweet. They, too, grow many generations of the resulting plants to identify and select the best. The ones with a future are named to reflect their hybridized status and also their new, individual names. For example, the towering, white flowered Natchez crepe myrtle is Lagerstroemia x 'Natchez', where the "x" indicates that it is a hybrid of two species that has been given its own name. A college professor once told me that the work he did breeding strawberries might eventually result in new varieties, but probably not in his lifetime. When you think about how much we gardeners dislike waiting for flowers to bloom, it is amazing that anyone has the patience to try to improve them.

Why Improve Plants
Some of the reasons so much energy goes into plant selection and breeding can be found in our food supply lines. The science of post harvest physiology is devoted to what happens between picking and plating, or the changes in a fruit or vegetable that affect how it travels to the consumer. One element in post harvest physiology is plant breeding. When hybridizing can make the skin less likely to rupture in transit or hold its color longer, it is explored.

Yes, taste is a factor, but delivery over long distances became a higher priority in the last century. When that consumer grew tired of pale, hard heads of lettuce and roses with little or no fragrance, the same breeders took notice and the tide has shifted at least a bit in recent decades.

A second important reason for improving plants is to overcome serious disease problems that prevent their cultivation because of their ruinous effects or high costs to prevent and control. The letters you see after a tomato name, such as VFN, indicate just such breeding, in this case to let you know the variety is resistant to verticillium (V) and fusarium (F) wilts, and to nematode infestations (N).

The desire to bring new and different flowers and plant forms to the market also drives the process, and the results can sometimes change our behaviors and gardens. Take petunias, the old-fashioned small, usually pastel spring flowers with distinctive fragrance that filled your nose as surely as the petals stuck to it. Then came improvements like bigger flowers, trailing habit, colors that seem to glow in the dark, and the culmination, Wave petunias. Not only do the plants grow quickly to fill beds and baskets, but the spring show lasts well into summer. Landscapers and gardeners who bed out annuals in the English way no longer need to replace spring annual petunias. In fact, there is almost no week in the year that we cannot enjoy this group of plants at one stage of growth or another in our regions.

Not all selections are as new as Wave petunias nor as singular. The original abelia species, A. chinensis and were crossed to produce the popular A. x grandiflora before your grandmother was born, while releases like the cultivar, A. 'Kaleidoscope' were unknown five years ago. These and other abelias are prized by gardeners and butterflies for their long bloom season, and the new selections were made to add color changes through the year.

Dwarf forms, or at least smaller versions of favorite plants like pampas grass, are the result of selection and breeding. The latest interest seems to be in choosing plants for their heat tolerance, an added benefit that will likely offer us more plant choices in coming seasons.

How to Mix it Up
Some gardeners are true to species only and some grow only native plants as they are found in nature. The rest of us tend to mix it up, using reliable old favorites and the latest releases together, especially when planting shrubs and trees. The best of these hodgepodge plantings repeat the good elements of both.

For example, a row of single-flowered purple althea makes a fine hedge row, especially when its form is repeated in a double flowered selection such as pink 'Blushing Bride'. If standard nandina, called heavenly bamboo, is in the landscape, you will notice it more if its form is embellished by including smaller versions like 'Bar Harbour'. Put the dwarf nandina in a big pot on the deck to tie that space in with the larger garden, or grow a line of them in front of the larger specimens to make both look better. If a huge lorapetalum or crape myrtle simply will not fit in your garden, take heart. Plant breeders have made it possible to select smaller versions of both these plants and many more.

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