Garden Help Desk: What can I do to make my whole peach tree produce fruit?
Courtesy Tiffany Draper
I have a peach tree that was planted before we moved into the house 3 years ago. Half of the tree consistently does not produce ripe peaches. It almost looks like 2 separate trunks that are wrapped around each other. One trunk produces good peaches every year. The other trunk gets small green fruits that stay tiny and green. That half of the tree doesn’t really grow much. I prune it every February, spray dormant spray every winter, and fruit tree spray after the blooms fall off. This year I did some fertilizer around the drip line. It killed my grass but I don’t know if it’ll make a difference. What do I need to do to get this half to produce?
Think of your peach tree (and most other fruit trees) as two trees in one. A tree with the desirable qualities in fruit texture and flavor is grafted onto the roots of a tree that has the vigor, disease resistance, and soil tolerance needed to thrive in your yard or garden.
One trunk of your tree is the peach cultivar with the desirable fruit characteristics you want. The other trunk is a sucker from the rootstock that was neglected and didn’t get pruned off. The root stock was selected because it would do a good job providing your tree with the resources it needs to produce good fruit, but fruit quality wasn’t important compared to root quality. To provide your “good trunk” with the best care you’ll need to cut off the problem trunk at the base and then prevent any more root suckers from coming up. Once you do that, you’ll have just your productive peach tree as the focus of your efforts.
I noticed a few other things in your question and photos that I want to mention.
You’ve been doing a dormant oil spray in the winter, but it’s best to do a delayed-dormant spray in the spring when the buds on the tree are swelling instead of in the winter. Pests that are overwintering on the tree are more susceptible to the spray at that time and it’s easier to avoid damage that can be caused by freezing weather shortly after doing your oil spray.
Courtesy Tiffany Draper
If your early spring application killed the grass, you probably applied too much fertilizer. Here are a couple of tips for deciding how much fertilizer you need.
The age of your tree is one useful guide. You can apply 1 oz actual N per year of tree age, but never more than 8 ounces per year. Apply in March. If you’ve been using ammonium sulfate (21-0-0 or 21% N) you would need to apply 5 times the amount of fertilizer product to get the right amount of actual nitrogen (at 21% N, ammonium sulfate is 1/5 N). You would apply 25 ounces, or about a pound and a half of fertilizer to a 5 yr. old tree.
Looking at the new shoot growth is another way to decide. Young non-bearing trees should produce 12 to 18 inches of new growth on branches each year. Most bearing trees should produce 8 to 12 inches of new growth per year. Peaches are a little more vigorous, so 12 to 15 or even 18 inches of new growth is what you’ll be looking for on your bearing peach tree. If your tree had been producing this amount of shoot growth, whatever nitrogen fertilizer you gave last year it was sufficient. If the new growth on your tree is less than expected, your tree may need some additional nitrogen. If your tree put on more new growth, use less nitrogen than you’ve been using.
There is grass growing up against the trunk of your tree. This provides a moist, sheltered location for Greater peach tree borers to lay their eggs on the trunk. Trees, including fruit trees, should have a wide vegetation-free area around their trunks. Keep grass at least 2-3 feet away from the trunk.