Whether you planted one tree or 75 this spring, having a plan to care for them is key to their survival.

Hopefully, the right species was selected to match the site and its conditions, a high-quality tree was purchased, and it was planted properly (not too deep). If this is the case, all that is needed is a little bit of after-care.

New Tree, New Root System:

When you transplant a tree, you typically leave quite a bit of the tree’s root system behind in the nursery. When balled and burlapped trees are dug with a tree spade and packaged in a rootball, approximately 90 percent of the tree’s root system is removed.

With a bare root tree, it might contain more fibrous roots, but it still lost enough roots to cause major stress and mortality in the first year or two. Unlike balled and burlapped or bare root trees, container grown trees have all their roots, but are grown in soil-less media that dries out quickly. Cutting some of the container grown tree’s roots is often necessary to remove girdling roots, as well as promoting new root growth that will move into surrounding soil.

If a newly planted tree has fewer roots, what does it need to grow a new system and become established in its new landscape?

Your New Tree Needs Water:

The new tree needs water on a regular schedule to support the leafy crown that does the work of making food. If you are relying on Mother Nature to provide enough rainfall, you might want to re-think that because your trees might not survive very long. By not making the time to water each week your trees might just become stressed and die.

Research has shown that soil around the root system (e.g., rootball) dries out every four to five days during the summer growing season. Most recommendations call for providing 10 gallons each week through a slow, deep soaking of the soils surrounding the root system or rootball.

Even if one-quarter-inch of rain falls, it will not soak the root system, so developing a program or schedule for watering is critical. If you choose to use a watering device, bag or “gator” that slowly percolates into the soil, remember that rainfall will not fill these devices and you will have to fill them every week during the growing season.

Mulching, Pruning and Fertilizing:

Another important component of young tree care is proper mulching of the soils surrounding the tree.

A natural wood chip mulch will help conserve soil moisture, prevent temperature extremes, reduce competition from grass and weeds, reduce soil compaction, and add organic matter to soils over time.

Make sure the mulch is not piled up on the trunk (the flare or taper at the base of the tree should be visible) and no deeper than three to four inches. It is better to spread the mulch out under the tree’s canopy or to the dripline (tips of the branches) than to pile it up thick against the trunk, creating an environment for root rots and diseases to infect the tree. Reapply a fresh, thin layer of mulch every three years, not every year.

It is best to give the tree a year or two to become established (growing new roots into the surrounding soil) before fertilizing or pruning because that stimulates new leaf growth. Pruning dead or broken branches, making proper cuts back to branch collars is fine and will not harm the tree, but you don’t want to diminish the young tree’s ability to produce food needed to grow a new root system.

Once the tree is established, it will be important to begin training pruning to develop good form, structure and strength in the tree.

Develop an after-care program or watering schedule for your newly-planted trees, instead of spending more money and time replacing dead trees that you thought would be fine on their own.

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613.