Top 10 Asked Questions About Fruit Trees
Fruit trees are a large part of our inventory, but they bring in more questions than any other category of plant. Our sales staff teamed up with our in-house orchard expert to answer the most asked questions about fruit trees in Wisconsin. We hope that after this brief read, you'll have a much better understanding of fruit trees, and you'll be well on your way to caring for the orchard on your property.
The Most Asked Questions:
- When is the best time to plant a fruit tree?
- Do I need to stake my newly planted fruit tree?
- Do I need multiple trees to get fruit? How does pollination work?
- When should I prune my fruit tree?
- Should I mulch my fruit trees?
- How often should I water?
- How do I protect them from deer?
- Why do I thin the apples on the tree?
- When should I fertilize my fruit tree?
- What do I fertilize them with?
- What are these web-forming bugs on my fruit tree?
When is the best time to plant a fruit tree?
Fall is an easier time to plant as fruit trees need less watering. Planting in spring/summer is still okay, but more frequent watering is required for proper establishment. If planting bare-root fruit trees, because of our northerly location, it is not recommended to plant during fall. Note: Johnson's Nursery does not grow or sell bare-root trees. Read more about planting container trees in the fall.
Do I need to stake my newly planted fruit tree?
No. With proper planting, semi-dwarf fruit trees shouldn’t need staking. That said, if there is a large fruit production and the tree becomes heavy, staking may be required.
Do I need multiple trees to get fruit? How does pollination work?
Pollination questions are the most frequently asked and with good reason. Pollination is the transfer of pollen from the male part of the flower to the female part of the flower. This is done via bees - without bees, there will be no fruit! (It’s important to never spray insecticides on blooming fruit trees or when pollinators are present.) Some types of fruit can be pollinated with their pollen and are “self-fruitful” or “self-pollinating.” Other types of fruit need pollen from another variety of the same type of tree to transfer pollen – this is called cross-pollination. To achieve this and for fruit to develop, pollination must occur at the same flower bloom time. Different bloom times will not allow for proper cross-pollination. Additionally, fruit trees need to be planted near each other for adequate cross-pollination. We recommend between 25 to 35 feet and no more than 50 feet.
- Apples - need to be cross-pollinated to produce fruit. Two different apple varieties (yes - different) or a crabapple will work provided they have similar bloom times. Crabapples have a longer bloom time than other apple species and will not interfere with the genetics of the apple fruit. For example, if you plant a Mcintosh Apple, and use a crabapple as a pollinator, the seed of the apple will be a hybrid (half McIntosh, half crabapple). However, the actual flesh of the apple will still be McIntosh. Which is okay! We aren’t eating the seeds, we are eating the flesh. Many of the apple varieties we carry bloom in early- to mid-May, making them great companions to each other. A Honeycrisp for example cross-pollinates with Cortland, Empire, Gala, and Jonathan.
- European plum - many (but not all) varieties are self-pollinating. European-type plums will set fruit on their own but will produce better crops with pollinizers nearby. Some examples that are self-pollinating are Mt. Royal, Stanley, and Italian. The Japanese/American plum hybrids need to be cross-pollinated (example: Black Ice® Plum, Alderman, La Crescent, Underwood, Waneta, Pipestone, Superior, etc.). In the case of Black Ice, it can be successfully pollinated with Toka, La Crescent, or even the plain species American Plum. For the other Japanese/American hybrids the universal pollinator is Toka.
- Tart cherry - all varieties, such as Montmorency, Mesabi, North Star, Sweet Cherry Pie, are self-pollinating so only one tree is needed to produce fruit.
- Sweet cherries - most need to be cross-pollinated with a different sweet cherry variety to produce fruit. Montmorency, Rainier, Lapins Since sweet cherry varieties all bloom at different times, it is important to have the right sweet cherry varieties for successful pollination (must bloom at the same time). At Johnson’s Nursery, we typically offer two sweet cherry varieties for this purpose. Lapins is self-pollinating. Rainier is not self-pollinating but can be cross-pollinated successfully with Lapins.
- Peaches – most varieties of peaches, including Redhaven and Reliance, are self-fruitful and do not require a cross-pollinator.
- Pears – require another cultivar for cross-pollination, such as a Parker Pear with a Bartlett.
See more about each fruit type in the Fruit Tree Availability >>.
When should I prune my fruit tree?
Most pruning is done while the trees are dormant. Normally, late winter to mid-April is a great time. Some summer pruning can be done but most pruning should be done when the trees are dormant. We have an extensive article about training & pruning fruit trees for more information.
Should I mulch my fruit trees?
Yes! You absolutely should. Having grass grow right up to the tree is not good as it will suck up water. The secondary issue is mowing. Mowing right up to the tree can cause damage to the trunk when the mowing blade nicks the base of the trunk which can then girdle the tree. You can mulch with bark mulch or even wood chips. Avoid the volcano-style of mulch and leave a ring around the base of the trunk free from mulch to prevent disease.
How often should I water?
Apple crops that are not watered will have smaller fruit, even if thinned. Apple trees not bearing fruit still need water. Not enough water will mean less growth. Typically, you want to see 12” to 24” of new growth on apple trees each year when young. Fertilizer and sufficient water are critical otherwise growth will be limited.
A note about true dwarf vs semi-dwarf: True dwarf apple trees are grown on dwarf rootstock making the tree naturally short. They also have a very shallow and small root system. Most true dwarf apple rootstocks MUST be watered when it gets very dry, or they will be stressed and not do well. This is one of the reasons why we grow and sell all our apple trees on semi-dwarf apple rootstocks.
How do I protect them from deer?
If you go the cage route, your fence needs to be tall as deer can eat tree branches up to about 5-feet in height. Hungry bunnies can also be an issue during winter. We recommend placing a tube protector around the trunk which helps keep the rabbits, mice, and voles from foraging on the tree trunks. Check out this article for more information about buck rub, deer browse, and deer proofing your plants.
Why do I thin the apples on the tree?
The point of thinning is to selectively remove fruit for the remaining fruits to grow larger and to increase the tree’s ability to form flower buds for the next year.
Fruit thinning is normally done from mid-June to about July 6th. To get good-sized fruit, thin your apples to six inches apart. Thin your apples to 12-inches apart for the largest possible sizes suitable for fruit baskets for gift giving. If you don't thin and the tree has too many apples, you usually get a crop of small-sized apples when ripe. Thinning after July 6th doesn't help much to increase their size. It will, however, help prevent broken limbs from the weight of too much fruit. The excessive weight of a heavy fruit crop can break the tree apart. Too much fruit on a tree is not good.
Peaches also are a crop that requires thinning in June/early July, just like apples. Peach trees produce so many flowers that without thinning you will only end up with golf ball-sized fruits when ripe. To get decent fruit size on peaches, it's imperative to thin the fruits to 12-inches apart. This means removing many fruits, but the reward of good-sized/quality peaches will make this task worth it.
When should I fertilize my fruit tree?
Younger trees respond well to fertilizer. Older, established trees typically don’t need it. The goal when they are young is to quickly get them to size with 18’ to 24” of new growth each year. Usually, there’s no need to fertilize older fruit-bearing trees as you don’t want to promote vegetative growth. It's best to fertilize in the spring. Normally May 10th-June 15th in southern WI.
The key to fertilizing is to measure the current year’s growth after September 15th. If your younger fruit tree grew over 30” that year, then reduce the fertilizer rate the following spring. If they only grew 12” or less, then increase the fertilizer rate the following spring.
What do I fertilize them with?
If you only have one to two fruit trees, using a liquid fertilizer like MiracleGro is fine. Use at a rate of one to two gallons per tree depending on its size. Granular fertilizer is good and cheaper than a liquid if you have lots of fruit trees. Use 10-10-10 and apply around the dripline of the tree at the rate you would apply if salting a good T-bone steak before eating. Since granular fertilizer is a salt, DO NOT OVERFERTILIZE! More is not better as it could burn the plant.
What are these web-forming bugs on my fruit tree?
Tent caterpillars! They will not seriously harm the tree but will eat many of the leaves and will cause you to lose out on getting a good growth rate. Tent caterpillars can kill the tree if it’s been heavily defoliated for four or more years or if the tree is stressed from lack of water. An easy way to prevent or limit tent caterpillars is to adequately water and inspect trees regularly, removing and destroying egg masses from branches before the eggs hatch in spring. If you have a garden house that reaches and has good water pressure, we recommend blasting the nest out of the tree to remove many of them. If not, you can leave them be or spray an insecticide to eradicate them. There are botanical options that conserve beneficial insects such as insecticidal soap, spinosad, and azadirachtin. There are lots of ways to deal with tent caterpillars. If you leave it, the tree will re-leaf out eventually.
Read more about the best pesticides for the home orchardist.