Green Thumb: Wee Trees

Lemon tree, very pretty. But will it grow in a pot on your deck?

Indeed it will. So will apples, peaches, nectarines, cherries, pears and figs, if the container is oversize and the tree is a miniature bred specifically for space-challenged gardens.

Container-grown trees have plenty of advantages. They won’t fill your yard with dropped fruit, as full-size trees do. They are short enough to be pruned and sprayed without a ladder, and they can be hauled to a new address if you move.

How small are these wee woodies? A tree labeled in size as miniature, such as Patio Apple ‘Garden Delicious’ or Patio Peach ‘Bonfire Red,’ steadily grows to approximately 6 feet.

“The tree’s mini, but the fruit will be standard size or larger,” says Geoff Hayes, nursery manager and buyer at Primex Garden Center in Glenside, which stocks both of these winter-hardy cultivars.

A tree labeled as a dwarf can grow to 10 feet if planted in the ground, but one in a container will not reach that height. By comparison, a full-size fruit tree planted in the ground typically grows 18-25 feet. A dwarf may be more difficult to manage than a miniature because of its size and is not always recommended.

Citrus trees can summer outdoors, but in this area, they need to come inside before the first frost. Relatively easy to maintain, they do well in rooms with plenty of sunlight, such as an unheated sun porch, and bear small white flowers in late winter.

If the plant is kept in a heated room, water it often and check frequently for pests. Citrus trees are widely available and can be found in a nursery’s greenhouse section.

Container-planted fig trees, usually too large to fit indoors, need winter protection of a different sort. Hayes suggests using building insulation fabric to wrap the trunk and branches “like a mummy,” completely covering the tree, which does not require light during the winter. Tie or tape the insulation in place. Very cautious gardeners will wrap the pot as well. The wraps can come off in late March.

Alternatively, an unwrapped fig tree can be stored in an unheated garage. Some light is OK, but no heat. “You don’t want it to leaf out on you,” says Hayes. A pampered fig will produce one crop a year.

If you’re looking for a real conversation piece, Joe Kiefer, co-owner of Triple Oaks Nursery & Herb Garden in Franklinville, New Jersey, suggests a banana tree. Triple Oaks sells three types, two of which produce ornamental fruit. The Banana Tree, a tropical plant and seed specialty company in Easton, sells two dwarf bananas with edible fruit: ‘Cavendish,’ which grows to 6 feet and produces yellow-skinned fruits resembling supermarket bananas, and ‘Jamaican Red,’ which grows to 7 feet and produces sweet, red-skinned bananas.

Banana rhizomes can be dug up, dried and stored under peat moss in a cool, dark place during the winter, much like cannas. But don’t try to overwinter a banana plant indoors unless you have a greenhouse: When in leaf, these plants require high humidity, constant warmth and about 12 hours of bright light daily.

Perhaps the most unusual miniature in commerce is the bonsai cabernet grape tree sold by catalog merchant Harry and David. Standing just 14 inches tall in its square, Japanese-style ceramic container, this tree has a thick, ancient-looking trunk, and a scale more suited to a desktop than a patio. At $59.95, the price reflects the careful pruning and shaping these 10- to 12-year-old trees have received.

When shopping for fruit trees, find out if the cultivar you want requires a compatible companion to produce fruit, or if it is self-pollinating. A self-pollinating tree will produce even more fruit if it has company. Gardeners with really limited space may be interested in the cleverly grafted trees that produce two or three types of apple on one tree, which pollinate each other. They’re sold as 2-in-1 and 3-in-1 trees.

Mail-order companies usually ship bare-root trees. Plant these as soon as possible in a 10- or 15-gallon container, or a pot that’s 28 inches or larger in diameter, after giving the roots an overnight soak in warm water. Trees sold in five-gallon containers at nurseries should likewise be transplanted after approximately a year and a half into a 10- or 15-gallon container. The pot material doesn’t matter, but resin or plastic ones are frostproof, add less weight to a deck and are easier to move.

At planting time, Hayes suggests using a commercial potting mix with a high peat-moss content and fertilizer already incorporated. Scott and Miracle-Gro are two companies that manufacture such a product. Bare-root trees should be planted with their roots barely under the soil line, because the trunk will rot if the tree is planted too deeply. When moving a container-planted tree to larger quarters, keep its soil line even with that in the new container.

Within a few years, you will need to do a root pruning to keep trees vigorous. This involves pulling the established tree out of its pot, soil still surrounding the roots, and trimming the roots back slightly. Add fresh potting soil to the pot and replant the tree, unless you are transferring it to a bigger container.
Diseases and pests will plague nearly every backyard gardener who grows fruit.

“I highly recommend that people grow apple scab-resistant cultivars,” says Robert Crassweller, professor of tree fruit at Penn State’s College of Agricultural Sciences in State College. Peach growers, however, are out of luck: “There are no disease-resistant cultivars of stone fruit,” he says.

For advice on preventing peach scab, peach leaf curl, cork spot, brown rot, borers and mites, Crassweller recommends Penn State’s detailed online guide to backyard fruit growing, found at http://ssfruit.-cas.psu.–edu.

The University of Dela-ware’s informational web site, also geared toward home gardeners, has a wealth of information at http://bluehen.ags.udel.edu/extension/in-for-mation/hg.

Spraying—what to use, and how often—is what fruit novices find most confusing. Professional orchards may spray as often as 16 times in a season, but Hayes says someone with only a few trees can limit spraying to three times. He suggests applying a dormant oil spray in late March or early April, on a day when the temperature is above 50 degrees, to kill overwintering insects on the trunk and branches. While the tree is in bloom, it can be treated with a fruit-tree spray, which includes chemical fungicides and insecticides. About two weeks later, when the blossoms begin to drop, fruit tree spray can be used again before the fruit develops. Trees can be sprayed more often, Hayes says, up until one week before harvest.

This is not the only possible approach. Kiefer prefers to avoid chemicals when fighting pests. University of Delaware experts caution against using insecticides during the bloom period, so as not to harm bees as they pollinate the flowers.

As if maintaining an established tree isn’t enough of a challenge, some gardeners like to try growing fruit trees from seeds. Mona Gold, a horticulture therapist who is director of special projects at Friends Hospital in Northeast Philadelphia, has coaxed plants from ordinary supermarket oranges, lemons, kumquats and pomegranates. This hobby requires patience: Gold waited six years to see fruit on a kumquat, and even longer for other fruits.

Fortunately, the gardener who buys a bare-root or container-grown fruit tree will not go gray waiting for fruit—most will produce a crop the first season they are planted.