Having fruit trees in your own backyard can be a fun and rewarding experience. However, raising fruit trees will be discouraging from the get-go if you do not prepare your planting site ahead of time.
Planting fruit trees on mounds is a great way to ensure sufficient water drainage and protect the overall health of your tree. Preparing your site by creating mounds is a simple way to set your tree up for success.
Benefits of Planting on Mounds
One of the most commonly cited benefits of planting fruit trees on mounds is improved soil drainage. If your yard does not drain well because of sloping, poor soil, or uneven landscaping, you should consider creating a mound for your fruit tree.
The mound will not only raise the tree’s elevation but the root ball’s elevation as well since it is not planted at ground level. When done properly, the structure of the mound diverts excess water away from the root ball, allowing the soil to drain more completely.
The removal of excess water is a necessary step in disease prevention. Many harmful fungi and bacteria in the soil, Phytophthora for example, can only thrive when the soil is too wet. Under their ideal conditions, these fungi and bacteria can reproduce quickly and destroy the entire root system.
Mound planting is also a good way to prevent certain pests. For example, dogwood borers, which can infest entire orchards, are much less common in sites where trees have been planted on mounds (source).
Finally, creating a mound can give you more control over the quality of your soil. Most veteran gardeners do not dig up one part of their yard to move the soil to a mound; instead, they supplement their native soil with compost and purchased garden soil. Purchasing soil allows gardeners to select soil with ideal pH levels, drainage abilities, textures, and nutrient contents.
Preparing the Site
Many gardeners underestimate the importance of preparing a planting site, not realizing that poor planning can derail an otherwise healthy tree’s chance of success. Proper site preparation involves three steps:
- Choosing the right location.
- Testing the soil’s quality and drainage ability.
- Building the mound itself.
Choosing the Location
Scout a location for your tree that meets the following criteria:
- Sufficient space. Research the mature height and width of the fruit tree you want to plant and keep in mind that its root system will be even more extensive. Fruit trees should not be planted where their branches’ growth may be obstructed by another tree’s branches.
- Plenty of sunshine. Every kind of fruit tree needs abundant sunshine to produce fruit.
- Some protection from wind. Some fruit trees are more tolerant of wind than others, but in general, your planting location should offer some shelter.
- Good airflow. Avoid the bottom of a slope, where cold air tends to settle. Likewise, avoid planting too close to buildings where warm air can get trapped.
Some fruit trees are more tolerant of shade, wind, and temperature fluctuations. If you do not have an ideal planting site in your yard, consult a local Extension agent for advice regarding which cultivars may suit your situation.
Testing the Soil
Even if you intend to supplement the soil in your yard with purchased soil, plan to conduct a general soil test and a percolation test. While purchased soil does help you control some variables, your fruit tree’s roots will be extensive enough that they will still be affected by the soil that surrounds the mound you build.
General Soil Test
Whether you intend to plant a flower bed or a whole orchard, a general soil test (link to Amazon) is a necessary step. Soil tests can give you the following information:
- The type of soil you have (loam, clay, sand, etc.)
- The pH level of your soil (how acidic or alkaline it is)
- The nutrients it contains
- The presence of harmful diseases, bacteria, or fungi (if any)
The results of your soil test can help you choose the right tree, prevent you from accidentally overfertilizing, or in the case of soil-borne diseases, steer you toward a healthier planting site.
Percolation tests measure your soil’s drainage abilities. The results of this test will help you determine how extensive your mound may need to be and how much modification your soil might require.
Follow these steps to conduct your percolation test:
- Dig a hole at your planting site approximately one foot in diameter and one foot deep.
- Fill the hole with water and leave it overnight.
- Fill the hole again the next day, using a stick to measure the water level.
- Every hour, measure the water level until the hole is empty.
Ideally, your water level will drop at a rate of one to three inches per hour. If the percolation rate is less than one inch per hour, you will need to modify your soil with compost, peat moss, or other organic matter. Spread a two-inch layer of organic matter over the soil near your planting site and use a tiller or garden fork to mix it into the existing soil.
If your soil’s percolation rate is greater than three inches per hour, be sure to maintain a good watering regimen. Soil that drains very quickly can still host healthy fruit trees, but you will need to be mindful of how little water your soil retains, especially during the hottest days of the year (source).
Building the Mound
When you are ready to build your mound, start by clearing the planting site of grass, weeds, large rocks, or other obstructions.
Aim for your mound’s highest point to be eight to twelve inches higher than ground level. This may require adding purchased soil. The diameter of your mound is a matter of personal preference and available space.
Shape your mound that it slopes gently away from where the tree’s trunk will stand. This will help excess water to run off. As you shape the mound, make sure you are filling in air pockets, dips, or other areas where soil may settle and collect water.
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Some gardeners also opt to build a small watering ditch surrounding the mound about three feet away from its center. If you choose to do this, dig your ditch approximately four to six inches deeper than ground level and only a few inches wide. The ditch will provide water to the tree’s lateral roots as they grow outward from the root crown.
Planting Your Fruit Tree
When to Plant
The best time to plant a bare-root fruit tree is in the late winter or early spring. Wait until the ground is no longer frozen.
You may have heard that fruit trees can be planted in the fall after the end of the previous growing season. This is not a good idea. Young trees cannot withstand winter temperatures while they are still trying to establish themselves.
Digging the Hole
Before you start digging at your planting site, check the moisture level of the soil. When you grab a handful of it, it should crumble rather than hold its shape.
Dig the hole right before you plant the tree instead of digging it ahead of time. If you dig the hole too far in advance, you may have issues with sidewall glazing. This occurs when the soil along the “walls” of the hole becomes hardened or weathered and does not allow the tree’s roots to break through (source).
It is important to dig to the right depth–once the tree is planted, you cannot correct for a hole that is too deep. You want the uppermost roots of your tree to be only an inch or two below the surface of your mound. Measure the root ball of your tree to determine the right depth and remember that some settling will occur after you finish planting.
Fruit tree roots mostly grow horizontally away from the tree’s trunk; in fact, many species of fruit trees do not grow long, vertical taproots at all. For this reason, you should also dig your hole twice as wide as the diameter of its existing root system. This not only aids in planting the tree but also helps the tree’s roots grow laterally and become established.
Planting the Tree
As you place your tree into the hole, gently spread out the roots. Avoid bending them or laying one on top of another. If there is not enough space to arrange them into a natural position, set the tree aside as you dig the hole wider.
Replace the soil into the hole slowly and carefully so that no air pockets are formed. Tamp down the soil firmly, but lightly; you do not want the soil to be too compacted.
If you notice the tree sinking as you fill the hole, loosen the soil, fill the hole more firmly, and set the tree back in place. Once your tree is firmly planted, reshape your mound if necessary.
At planting, give your tree some water. Water slowly and take care not to erode the soil near the tree’s trunk. At first, you will need to water the root ball directly, since the roots will not have grown outward yet.
If you plan to use a drip irrigation system, place your emitters in close proximity to the root ball while your tree is still getting accustomed to its new site. Soaker hoses are another good tool that can deliver water to the root ball without getting the trunk unnecessarily wet.
Fertilizing is not recommended at planting time. Depending on the fruit tree you choose and the nutrients available in your soil, you may not need to fertilize at all during your tree’s first year.
Consult a local Extension agent, nursery, or another local expert to learn when you should begin adding fertilizer to your tree’s soil.
Unless your planting site is sloped, exposed to high winds on a regular basis, or unless your tree’s health indicates a need for it, you should not plan to stake your fruit tree after planting.
If staking is necessary, use non-abrasive ties to anchor the tree to the stakes. Do not place the ties any higher than absolutely necessary. Your tree should still be able to spring into an upright position after being gently bent to one direction.
Do not be startled if your staked tree appears to be bending or swaying too much during high winds. The stakes should prevent the tree from being uprooted, while still allowing some flexibility. Flexibility encourages the tree to produce the tissue that is necessary for a strong, healthy trunk.
Once your tree is planted and staked (if necessary), apply mulch to your mound.
Pine bark, wood chips, pine needles, dry leaves, and hay are all good mulch options and are widely available at garden supply retailers. You will need enough to create a two to four-inch layer over the top of your mound.
As you apply mulch, avoid putting any right up against the tree’s trunk; leave a few inches of space around the trunk. This will help prevent stem rot.
Mulching is not absolutely crucial, but it is still strongly recommended. Mulch helps to regulate moisture retention, soil temperature, weed growth, and mound erosion.
Care and Maintenance
When caring for trees planted on mounds, make proper irrigation a priority. It may take several months for you to learn how quickly your mound dries out, especially if you purchased soil to add to your existing soil, so close observation will be key.
You may find that water runs off one side of your mound more quickly than another or that some spots seem to retain water longer than others. If you use a drip irrigation system, these issues are easy to solve, since you can simply place your emitters in the spots that tend to dry out the quickest.
If you plan to use a ditch system to water your tree, you may need to supplement with water closer to the tree’s base during the first year after planting (source).
Your mound itself should be easy to maintain. If your mound becomes eroded and misshapen due to heavy rain, wind, etc., simply build it back up in the areas that need it. You can use existing or purchased soil for this.
Mounds are easy to construct and maintain, ensure good water drainage, and help prevent disease. They are especially beneficial if your existing soil is not ideal for the fruit tree you want to cultivate. If you are considering adding a fruit tree to your backyard garden, planting on a mound is a great way to set yourself up for success.