There's a housing trend in the United States that plant breeder Floyd Zieger views with increasing satisfaction. It's the growing popularity of decks and patios - those outdoor living spaces that can add so much to the pleasure of a summer at home.
Without consciously working to that end, Dr. Zieger has been professionally involved in a project that nicely fits in with deck and patio trends - the miniaturization of trees, fruit trees in particular.
So because of Zieger, and others like him, a small but increasing number of householders are discovering that the deck is much more than a place for the barbecue grill: It's the site of the home orchard as well!
An orchard? Well perhaps that's exaggerating things a little.
But 30 pounds of peaches from a tree in a tub isn't insignificant, either. And we're talking about a tree that tops out at three feet!
Zieger works for Dave Wilson Nurseries, near Modesto, Calif., a research-and-development nursery that brings new varieties into being, then licenses their reproduction out to commercial nurseries around the country.
More than three decades ago, he began working on a project that would reduce the size of trees without sacrificing fruit size or quality. The aim was to develop naturally small trees, not those that are small because they have been grafted onto special dwarf rootstocks.
And he has succeeded.
Originally Zieger had commercial fruit production in mind, because it has been repeatedly proved that fruit yield is significantly higher from an acre of dwarf trees than from an acre of standard trees. In simple terms, if four small trees can be planted in the same space taken up by a standard tree, the four trees combined will outproduce the single larger tree.
But slowly, as Zieger's trees came down to three feet and in some cases less, people recognized that containerized fruit production for tight city and suburban situations was a practical possibility. Decks, patios, rooftops, and sunny porches suddenly became possible fruit-growing sites.
``Tub orcharding,'' as it might be termed, is barely in its infancy.
``We haven't even scratched the surface,'' says John Miller, whose Miller Nurseries in upstate New York raises a number of Zieger-developed trees. By far the majority are destined for in-ground planting even in suburban backyards.
But he says that ``when we ship trees to Manhattan, it's almost certain they'll end up in tubs on some rooftop.''
Mr. Miller feels that most trees belong in the ground, unless the only suitably sunny sites are where there is no soil.
On the other hand, he does point out a major advantage to tub planting: Tree species not hardy enough for the far north can be grown, yield their fruit, and then be wintered over in a shed or in a garage.
The tree that needs bright summer sun can be stored in very poor light conditions during dormancy. This makes even fig production a practical home garden possibility - even in Minnesota.
Zieger's work has focused principally on peaches, nectarines, apricots, plums, cherries, and almonds.
But, says Miller, figs, apples, and blueberries are also available in sizes (two to six feet) that are suitable for tubs, half barrels, or other kinds of appropriate containers.
Apart from their fruit production, Zieger suggests that tub trees are valuable as ornamentals. As trees have been made more compact, he points out, the blossom buds have been brought closer together on the branches. So in the spring these fruit trees ``are as beautiful as any flowering shrub.''
The foliage, too, remains attractive for much of the year - sometimes even into the fall when it colors up attractively.
Zieger's advice for cultivating tub trees is straightforward:
Make sure to plant the trees in a light planting mix so that good drainage is assured.
Fertilize twice a year with a balanced organic or slow-release chemical fertilizer.
Another option is to feed half-strength liquid fertilizers once a week.
Water regularly (every day when it is hot), because, unlike ground-planted trees, your tubbed specimens cannot send roots down into the water table.
Pruning these trees is virtually unnecessary.
``They're so compact, they just don't need it,'' Zieger says about these new high producers.