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Widespread distribution of fruit seeds in the wild is for the birds

By Tony Tomeo

In the wild, fruit is intended to help perpetuate the species that produces it. Plants that produce fruit are not at all concerned with feeding the animals or people who consume the fruit, but merely provide the fruit as payment for transportation and dispersion of the seeds contained within the fruit. This arrangement has been mutually beneficial longer than anyone can remember, and has become even more advanced during the past few millennia with plant breeding.

For example, wild blackberry brambles produce berries that several different types of birds like to eat. The birds cannot, and probably would not want to, separate the seeds from the soft parts of the fruit, so ingest the seeds together with the fruit. The birds then "deposit" the seeds wherever they go. Some seeds get dispersed locally, where the berry vines already grow well. Some get dispersed farther away, where the vines would like to try to get established.

Plant breeding has enhanced the quality of most types of fruit, but has also enhanced the symbiotic relationships between the fruit trees and the people who enjoy the fruit. By producing larger, tastier and more abundant fruit, all sorts of fruit trees have ensured that their progeny will always be perpetuated for home gardens (although not by seed, but by cloning). However, the unnaturally large and abundant fruit has made them dependent upon their human benefactors.

Except for persimmon and only a few others, almost all deciduous fruit trees (not citrus--they're evergreen!) need to be pruned while dormant in winter. This includes the "pome" fruits, such as apples and pears, and the "stone-fruit," such as plums, prunes, peaches, nectarines, cherries, apricots and almonds. Without pruning, these trees eventually get so overwhelmed with their own fruit that their limbs break and become disfigured. (Stonefruit of the genus Prunus contain single, large seeds known as stones. Almonds are actually stones of a tough fruit that dries and splits open as it ripens.)

Of course, every type of fruit tree needs different, specialized pruning. Trees that produce smaller, lighter fruit typically need less pruning. Cherry trees, for example, may not need major pruning while young because they can sustain and support the weight of their own fruit. However, even young peach trees need aggressive annual pruning to compensate for their cumbersomely heavy fruit. Regardless, all of the deciduous fruit trees that need winter pruning are far from low-maintenance.

Pruning of deciduous fruit trees needs to be performed while the trees are dormant, after the leaves fall off, and before buds begin to swell in very early spring. Once bloom begins, sap is already running, and it is too late to prune. Because winter is so mild locally, the time to prune is somewhat limited.

Sunset's Fruit Tree Pruning explains in detail the specialized pruning needed by each type of the deciduous fruit trees. Also, Common Ground Organic Garden Supply and Education Center provides information about fruit tree pruning, both at its store at 559 College Avenue in Palo Alto and at its website at www.commongroundinpaloalto.org. Call 650.493.6072 for more information.

Tree of the Week:
Fruiting Quince

Fruiting quince, Cydonia oblonga, is the "other pome fruit" that is similar to pear but is one of the very few deciduous fruit trees that does not need much pruning. Unlike pear, it blooms and produces fruit on new wood (stems that developed during the previous year), so too much pruning actually limits the production of fruit.

Mature quince trees are 10 to 20 feet tall and wide. The white or pale pink flowers that bloom in spring look like apple blossoms, but are slightly larger. The 3-inch long, slightly tomentous (fuzzy) leaves turn yellow in autumn.

Quince trees are somewhat rare because the aromatic, 3-inch wide fruit is so old-fashioned. Like crabapples, most types of quince are not eaten fresh but are used to make jellies and pies. Both quince and crabapple fruit contain so much pectin that they are often added to fruit that lacks pectin, such as berries, to make jelly.

Horticulturist Tony Tomeo can be reached at lghorticulture@aol.com or 408.358.2574.