Who eats most of the fruit from your backyard fruit trees? Is it your family and friends, or the squirrels and roof rats? Does too much of it rot on the ground? What if you could pick all the fruit without a ladder, it was higher quality, and the tree took up less space in your garden?
I've been hearing about the advantages of shaping deciduous fruit trees when they're small and thinning the fruit for years, but Ann Ralph's talk at last month's San Francisco Flower and Garden Show was the most concise, comprehensive, and persuasive presentation I've seen.
“Routine care is easier if the tree is as tall as you” rather than twice your height, Ralph said. That care includes pruning twice a year (especially in summer), thinning and harvesting the fruit, and monitoring it for pests and diseases. Smaller is also better because “people radically underestimate the production capacity of an average-size fruit tree, and overestimate the amount of fruit they actually use,” she said. For instance, a 6 ft. apple tree can produce at least 100 to 150 apples. With a 12 ft. tree, “you can't get up there to thin the fruit, and it will have lots of wormy and inferior fruit.”
Counterintuitively, to get a small tree you don't want to start with genetic dwarf or ultra dwarf varieties. Semidwarf fruit trees, which have fruiting wood called scions grafted onto a semidwarf rootstock, are the ones to buy. The semidwarfs are hardier, have stronger root systems, are bred for disease-resistance and fruit quality, and offer the widest selection of varieties. Though semidwarfs will reach 25 ft. without pruning, they are easy to keep small with pruning, Ralph said. “Pruning is the best way to control the size of a fruit tree.”
“If you can do anything for a fruit tree,” she said, the most important thing is to cut your bare-root sapling knee-high as soon as you bring it home from the nursery and plant it. That's right, take that 5-8 ft. high sapling you carefully selected and cut it knee high! It's the hardest cut to make, and the most important one. New branches will sprout from dormant buds lower on the trunk. You then choose three main branches to form the “scaffold” of your small tree, and help the tree develop good form while it's young.
Furthermore, “bareroot is the best way to plant a fruit tree.” You get the best price, the trees have never been in a container so you don't run the risk of circling roots, you don't have to remove the fluffy nursery soil before planting, and “you can make the low prune while the tree is still young enough to manage it,” Ralph said.
Fruit trees can set more fruit than they can support, so thinning the fruit “is as important as pruning, and as psychologically difficult” as the knee-high cut, she said. If you can remove up to 75 percent of the fruit when it is “as big as your thumb,” your reward will be larger and higher-quality fruit.
The exception is citrus trees, which can handle the amount of fruit they set, and which don't need the routine pruning that deciduous fruit trees do. Another exception is fig trees, which “you can prune any way you want.”
Ralph's brilliant book, Grow a Little Fruit Tree: Simple Pruning Techniques for Small-Space, Easy-Harvest Fruit Trees (Storey Books, 2014, 168 p.) gives more details.
Lemon and other citrus trees don't require the knee-high cut or the routine pruning that deciduous fruit trees do. Choose dwarfing rootstocks, and “shape citrus as you see fit,” Ralph says.
The fruit on this apricot tree is much too prolific for the tree to handle, and growing far too close together. Once the fruit is properly thinned, this branch will sustain 2 or 3 larger, better tasting, healthier apricots.
Rather than buying the largest container you can, Ralph advises choosing a younger, thinner deciduous fruit-tree sapling in bareroot season, around the beginning of the year. Typically, you will see saplings over 5 ft. high. Make the all-important knee-high cut either before you leave the nursery, or as soon as you plant it.
© 2016 Tanya Kucak