Garden Tips: Dwarf trees make spraying for pests easier

Have you ever thought of growing an apple, pear or cherry tree? While the idea of growing your own fruit is attractive, it is a decision that requires careful consideration.

Home gardeners should plant only dwarf apple, pear and cherry trees because they are easier to spray for pests and easier to prune.

Apples, pears and cherries are all attacked by insect pests that lead to wormy, inedible fruit. These pests can only be controlled with regular sprays of insecticides during the growing season. It is difficult for home gardeners to adequately spray fruit trees that are greater than 10 feet tall. If gardeners give up and abandon attempts to control these wormy pests, they will be breaking the law. This is because Washington law requires that these pests be controlled on backyard trees and in commercial orchards to protect the region’s commercial fruit industry.

Dwarf fruit trees are ones that do not grow to the mature height of a standard fruit tree. You may have seen commercial orchards in our area with dwarf apple trees growing on a trellis or supported with stakes. These are dwarf trees grown on dwarfing rootstocks. The top variety, or scion, is growing on roots or a rootstock of a different variety that restrains the growth of the tree.

Dwarf is a relative term. A semi-dwarfing rootstock like EMLA 7 reduces the size of an apple tree by 40 percent, allowing it to grow to a height of only 10 to 16 feet. This is still a fairly large tree. A tree with a dwarfing rootstock, such as EMLA 9 or EMLA 26, would be preferable because the trees will grow to a height of only 8 to 12 feet. EMLA 27 (M 27) is considered extreme dwarfing and will yield a tree that grows to a height of 6 feet. However, a tree on this rootstock will require the support of a trellis or stake, because its root system is restricted. Because of its limited root system, it will also need more frequent irrigation and fertilization.

While apples with dwarfing rootstocks have been available for a while, it is only in recent years that cherry trees with dwarfing rootstocks have become available to home gardeners. Standard cherry trees growing on their own roots can reach a height of 40 feet. Home gardeners should be able to find cherry trees growing on dwarfing rootstocks, including Colt that reduces size by 20 percent, Gisela 5 by 50 percent to 60 percent, Gisela 3 by 65 percent to 70 percent, or Newroot-1 (Zaiger Dwarf) by 75 percent. Cherry trees growing on Newroot-1 are small enough for growing in containers.

When it comes to pears, home gardeners are not likely to find trees with fully dwarfing rootstocks. Old Home x Farmingdale 87 (OHxF 87) rootstock and OHxF 513 are used to produce semi-dwarf trees that are reduced by 30 percent in height, producing trees about 25 feet tall. Vigilant pruning is still needed to keep their size in check.

If you plan to invest in an apple, pear or cherry tree, make sure it is a dwarf tree. Check the type of rootstock and look for those mentioned earlier. If you cannot find any locally, consider ordering online. Two nurseries that cater to home gardeners and offer fruit trees with dwarfing rootstocks are Raintree Nursery (raintreenusery.com) in Morton and One Green World (onegreenworld.com) in Portland.

When it comes to backyard fruit trees and their care, smaller is better.

This story was originally published March 12, 2017 at 6:39 AM with the headline "Garden Tips: Dwarf trees make spraying for pests easier."