Ornamental trees add value to homes, businesses, and common areas. However, they do need some maintenance to keep them healthy. The exact dates of the maintenance will vary depending on where you are located. This article covers regular maintenance tasks for established ornamental trees. Trees planted within the last three years require different care.
Soil Tests
A soil test is recommended every three years. A sample of the soil where your trees are growing is sent to the state soil lab along with a form detailing what you are trying to grow. The soil lab sends you a report along with fertilizer recommendations for those plants.
Mulching Trees
The soil beneath the canopy of large shade trees such as a pin oak is full of roots that spread out two to three times the size of the canopy. The excessive shade under the canopy makes growing anything there, especially turf grass, difficult. For young trees that are growing rapidly, mulch should be spread to a depth of three inches out to the dripline. Leave a gap of three inches between the trunk and the first mulch. As the tree grows, extend the mulch out so it is always out to the dripline.
Older trees may be so large that mulching out to the dripline is not practical. A mulched area of approximately three feet from the trunk will protect the tree from string trimmers and mowers, which can inflict severe wounds to the trunk. While not usually fatal, these wounds can allow diseases and pests an entry into the tree trunk.
Hardwood mulch decays at the rate of about an inch per year, adding organic matter to the soil. Every spring, an inch of additional mulch should be put on top of the old mulch to keep the layer of mulch three inches deep. This retards weeds and stabilizes soil moisture and temperature.
Low growing ground covers can be used instead of mulch under the tree. An example of a good ground cover for under trees is vinca minor. It is low to the ground and has lovely blue flowers.
Fertilizing Trees
Trees should be fertilized in the spring with a fertilizer that is at least half slow-release fertilizer. The slow-release fertilizer will feed the tree for the rest of the year. The instant release component of the fertilizer will give the tree a boost while it is putting out leaves and flowers. Remember to follow label directions. Adding more fertilizer than the instructions say to will harm the tree.
Scientists used to recommend digging holes under the dripline and dividing the fertilizer into these holes. New research suggests that method can do more harm than good. Instead, broadcast granular fertilizer under the dripline of the tree. Most granular fertilizers require water to activate them and help them reach the roots of the tree, so plant to water within 24 hours of spreading the fertilizer.
If your tree has turfgrass under it, the fertilization schedule for turf will provide adequate fertilizer for the tree. Do not add fertilizer just for the tree if you are fertilizing the turfgrass under it. Ground covers under a tree will benefit from the fertilizer you broadcast under the dripline and do not require additional fertilizer.
Watering Trees
Trees suffer more from over watering than under watering, especially if a water hungry turf grass is being cultivated under them. Established ornamental trees should be watered deeply every two weeks in the spring and summer and every month in the winter. Native trees do not require supplemental watering unless there is a drought.
When watering trees, the goal is to water them deeply, so the roots stretch as far as possible to soak up the water they need. Applying ten gallons of water per inch of tree diameter soaks the soil twelve inches deep. This is where 90 percent of the tree roots are. For trees over ten inches in diameter, apply 15 gallons of water per inch diameter.
Water your trees before ten a.m. Try not to get the foliage wet when watering. Direct the water to the root zone to reduce evaporation. In a hot climate 40 percent of the water sent out by a sprinkler evaporates before reaching the ground. Not only does that water not help your trees, but you are also paying for water that does not benefit your landscaping at all.
Pruning Trees
Pruning trees should be done in late winter or early spring. Do not prune oak trees between February and July to protect them from oak wilt. An established ornamental tree does not need extensive pruning. Remove suckers on the trunk, dead, diseased, or broken branches, and lightly prune for shape.
Do not take off more than one third of the tree or it may die. Plant the correct tree for the space and do not depend on pruning to prevent a tree or shrub from growing too large. Please do not top crape myrtle trees (referred to as crape murder among professionals.)
Fruit trees require a different pruning strategy to keep them small enough to harvest the fruit from the top and maximize fruit production. I won’t cover that here.
Watch Out For Herbicides
Trees are broad leaf plants. Applying herbicides, especially “weed and feed” products, under the tree canopy can cause a decline in the tree’s health or even kill it. Do not apply such products within 40-50 feet of the tree trunk. Even products that say they are safe for trees may not be safe. If the tree is already stressed, herbicides such as post emergents for broad leaf plants may more severely affect the tree.
Benefits Of Native Trees
When choosing a tree to plant in your landscape, look at the trees that are native to your region. These trees are already adapted to soil conditions and rainfall amounts where you live. The trees have grown resistant to common tree diseases and pests, so you do not have to spend as much time caring for them. After the tree is established, you will only need to water it during a drought.
Have Questions? Call Us
If you have questions about caring for your trees, give us a call at 931.692.7325. The staff at Garden Plants Nursery can help you find native trees for your landscape and tell you how to care for your existing trees.
