Three of my fruit trees have stopped producing. They were productive when we moved in two years ago but not now. I've been told that I need to fertilize them before they leaf out. Also, they're planted on a twenty to twenty-five percent slope, so I dug trenches around the trees for watering. Can you shed some light on my problem?
Apples, Cherries, Plums, and other deciduous fruit trees fail or stop fruiting for several reasons.
The primary one for a sudden decline is aggressive pruning during the winter that removes the fruiting spurs and the spring bloom. The problem is corrected by adjusting your pruning.
If the trees are flowering but not setting fruit, then you have a pollination problem.
The chief pollinator of fruit trees is Honey Bees; unfortunately, there has been a decline in the number of active bees. Cold, wet, rainy conditions during flowering decrease their activity. The conditions were okay last winter but not perfect.
Another contributor to the lack of fruit is the overall health of the trees. Those trees that are struggling to produce poorly. This is measured by the lack of or little new growth and dieback in the canopy. You might find that sections or branches don't break dormancy or die during the growing season.
The slope may be contributing to the problem as soil erosion during the winter months could be burying the trees. The soil will build upon the backside or the downward slope at the tree trunk(s). You need to annually remove all the excess soil, down to the top of the first root and then channel the water away from the crown or base of the tree(s). You have effectively solved this point by trenching
You then mulch the area under the canopies to conserve moisture.
Except for apples and pears, deciduous fruit trees are not watered more than twice a month. The early stages of dormancy begin after Labor Day, so you stop watering altogether at that time.
A large basin should be constructed each spring and then removed in November. They should be six to eight inches tall and extend from the trunk to beyond the canopies. Because of your slope, the front side of the basin will be much higher than the back.
Wet winters and excessive summer watering leads to root rot that doesn't show up until the following year as dieback.
Other reasons for fruit trees to fail to bear fruit but doesn't apply in your case are: the trees are too young.
Trees started from a pit or seed are unpredictable and usually, disappoint. It doesn't happen very often, but frost during the flowering can be a problem.
Selecting a variety that requires more winter chill than your area receives affect fruiting.
Overfeeding can be a problem also. Here the trees are lush during the growing season but fail to flower the next spring.
Deciduous fruit trees are fed no more than three times during the growing season. The first application is applied in March or April with a follow-up feeding in June/July or in the fall.
My first thought too solving this problem is to review how your trees were pruned.