Where’s the Fruit?

As an arborist, I often feel like I need to double as a detective. Trees, obviously, cannot tell us verbally how they are "feeling" or why they are behaving in a certain way. We have to look for clues as to what is possibly going on with them. When I am asked why a tree is performing poorly, oftentimes I need to swap out my helmet for a Sherlock Holmes cap and start digging around, asking questions of the tree's caretaker and standing back to observe the environment in which the tree exists.

One of the questions I am asked often, especially this past year, is "why didn't (or doesn't) my fruit tree produce fruit?" The answer to this can be complicated and can have many explanations. The fruit trees we typically grow here in Ohio are apples, pears, peaches, nectarines, cherries, and plums. These trees are all in the same rather challenging plant family, the rose family or Rosaceae. This family of trees (and shrubs) is susceptible to many pests, diseases, and seasonal issues. The biggest culprit last year was a late spring freeze near Mother's day [See Fig. 1]. This polar vortex sent Ohio orchard owners scrambling to save their precious buds, flowers, and very young fruit. There was also a freeze in mid-April that killed a lot of the very early blooming flowers of peaches especially. 

[Fig. 1] Temperatures dipped below and to freezing on May 9th and 12th in 2020.

Cold is a component that is very important to fruit production. Fruit trees need a certain amount of "chill hours" below a given temperature to recognize that winter has occurred and that it is time to wake up and flower. Typically, here in Ohio, we get plenty of chill hours. Our issue is either extreme and prolonged cold or a very cold dip in temperature after a warm, late winter spell. Very cold winters can kill dormant flower buds and even entire trees. This may be the case if your tree does not flower as expected in the spring. In the case of warm periods before a freeze, the tree may flower beautifully, but the flowers are damaged and cannot create that yummy crop you had been dreaming of.

Apples and pears are the most cold-hardy of the rose family fruit trees and produce fruit most reliably in our climate.

Windy, rainy, and chilly weather in spring also presents an obstacle for some of our tiniest workers, the pollinators. Native bees, honey bees, and bumblebees need to be present if any fruit is to develop on your tree at all. However, these gals are reluctant to venture out in search of pollen if the weather is wet and gusty and the temperature is below 55 degrees Fahrenheit. Thank goodness each flower is viable for 3-4 days and flowers do not open all at once. If the sun comes out for even one nice afternoon, you should have some pollination even in the worst weathered spring. Attracting bees to your yard with bee-friendly perennials and reducing the use of insecticides while bees are active should also help your future yields.

Along with pollinators, many fruit trees need a pollinizer as well. Peaches, tart cherries, nectarines, and some plums are self-fertile and will produce a crop without the help of another tree. However, apples, pears, and sweet cherries need a second tree of the same species, but a different variety, to cross-pollinate with. The trees should have overlapping bloom times and be within 300 feet of each other to be the most successful. It is interesting to note that crabapples are the exact same species as apples and will pollinate apple trees as long as they flower at the same time (and the crabapple is not a sterile variety). It is also interesting to note that cross-pollination between different varieties does not change the nature of the fruit. A Red Delicious apple tree will always produce Red Delicious apples even when pollinated by a Snowdrift crabapple [See Fig. 2], but if the seeds from the cross-pollination are planted, an entirely different and surprising fruit may be produced.

[Fig. 2] A Red Delicious tree pollinated by a Snowdrift Crabapple will still produce a Red Delicious apple.

So, if you had good fruit-producing weather during winter and spring, saw many bees working your full bloom flowers, and are sure you have a pollinizer nearby, we will have to look for more clues.

[Fig. 3] The dripline of a tree

1. Is your tree getting enough sun?
   Fruit trees have the best yields with at least 8 hours of sun a day.

2. How old is your tree?
   Most fruit trees need to be between 3-5 years old before they flower and set fruit.

3. Is your tree starved for nutrients or has it been fertilized too much?
   Producing flowers and fruit takes a lot out of a tree. Fruit trees definitely benefit from a spring application of slow-release organic fertilizer to give them a boost of energy. You can also spread cow manure or compost within the dripline [See Fig. 3] to improve the soil and nourish your tree. On the other hand, over-fertilization with quick-release synthetic fertilizers high in nitrogen will cause your tree to grow too much. This vigorous green growth is at the expense of flower and fruit production and will make your tree more susceptible to fungal and bacterial attack and look delectable to deer and insects.

4. Has your tree been pruned lately?
   Pruning fruit trees during the dormant season each year can improve fruit production. It is recommended to remove 25% of the tree’s canopy (depending on age), concentrating on limbs that are broken, dead, crossing, growing into the tree, or growing vertically (water sprouts). Pruning to maintain good air circulation and sun penetration within the tree by making the correct thinning cuts will assist in keeping leaves dry and less susceptible to disease. It is important to note that fruit production is better on more horizontal limbs than limbs that grow more vertically.

5. Is your tree getting enough water during our very hot, dry summers?
   Without the proper hydration, fruit will suffer so that the tree itself can survive. Removing turf and weeds within the dripline of your tree and applying a thin 2” layer of organic mulch can help retain moisture and reduce competition. Apply supplemental water slowly and deeply during times of drought.

6. Do you suspect your tree may be infested with insects or infected with a disease? 
   There are many insects, mites, fungi, and bacteria that love to feast on and infect fruit trees. Dormant oil sprays in late winter and fruit-friendly fungicide sprays during the spring may be needed to produce edible fruit.

If you have a fruit tree that needs pruned, fertilized, or inspected and treated for disease and insects, call Russell Tree Experts and entrust their proper care to our team of certified arborists. We would love to care for your trees and help you get to the bottom of “the mystery of the missing fruit”.

May you have a fruitful year ahead!

Krista Harris | Regional Manager, Russell Tree Experts

Krista grew up in the central Ohio area and became an ISA certified arborist in 2017. She graduated from The Ohio State University with a Bachelor of Science in Crop Science and a minor in Plant Pathology in 2000 and has been in the green industry ever since. Her favorite trees are the American sycamore, American beech, and giant sequoia.

• BS in Horticulture Crop Science, The Ohio State University

• ISA Certified Arborist® OH-6699A

• ODA Comm. Pesticide Lic. #148078

• CPR & First Aid