The drought, homeowner wishes, new development — whatever the reason, a new tree was planted, and now it’s time to make sure it thrives. As a tree care provider, it’s your responsibility to integrate solid best management practices for mature specimens, new additions and trees of an intermediate age.
Providing for newly planted trees is not as simple as it may sound. There’s a lot more to it than just a little water and mulch. The long-term success of any new installation is largely due to proper planting procedures and follow-up care in the first year after planting. Mistakes made early on in a tree’s life are not easily made up for later on.
Staking is generally considered a no-no, as the benefits simply do not outweigh the negative consequences that usually occur as a result. In the first year following planting, it’s crucial for trees to develop a strong matrix of lateral roots that provide structural support for the stem and branches. When newly planted trees are allowed to sway and bend slightly in the wind, the natural response is to produce roots in sufficient quantity and size. On the other hand, when staked, new plantings aren’t exposed to the same forces and, as a result, often don’t develop as many structural roots.
As with many procedures or management practices, there are exceptions. In this case, trees that have been planted in windswept areas that are overly prone to strong prevailing winds may need some level of staking to prevent being blown out of the soil. If so, three guidelines should be adhered to in order to help the tree develop a lateral root system. First, the stem should be tied to the stake loosely, in such a way as to allow an inch or two of lateral movement. Second, a wide strip of nonabrasive material, such as rubber inner tubes, old T-shirts, drapery remnants, soft canvas, etc., should be used around the trunk to create a snowshoe effect, rather than one that causes damage to the bark and cambium. Third, the stake should be removed after a year’s time to allow for future root development. A tree that is dependent on a stake is not a sturdy long-term element in the landscape.
To gain valuable insights into the makeup of the soils that surround the newly installed specimen, it’s wise to sample the areas just outside of the root-ball. Many valuable insights can be gained from a soil test, such as the percentage of organic matter, pH, soil type, cation exchange capacity and concentrations of various nutrients. Gathering this information will indicate the need for added nutrients, pH adjustment and the likely rate of water infiltration surrounding the tree. Starting with these foundational measurements will help provide for the tree’s needs for years to come.
Unless a nutrient deficiency symptom presents itself, or a soil test indicates a need, fertilization is generally not necessary in the first year after planting. In fact, not only is it not needed, it can be detrimental. Absorption of high quantities of nutrients by a new tree often leads to excessive growth of the new shoots at the expense of the root system. As mentioned above, a foundational goal for establishment is for the tree to develop an extensive lateral root system that will support the tree and serve to take up water and nutrients from the existing soils. Preferential growth of shoots over roots can be problematic. When fertilizer application is required, seek to provide an even application across the entire root system.
No, No, Nanette
At this point, you might be thinking: “OK, so no staking and no fertilizing … what can I do?” Initial tree care is equally about what not to do as it is what to do. In short, fertilizing, staking — probably not. Soil testing, mulching and watering — yes. Pruning falls into a third category of “maybe.”
There are many benefits to mulching. However, like many other tree care operations, it must be done in balance with other procedures and the overall environment where the tree is growing. The main goal of mulching is to replicate the conditions where the tree is native. An urban lot comprised of turfgrass growing over the top of subsoil is rarely a suitable site for trees.
One of the best ways to duplicate what Mother Nature intended is to apply wood chip mulch over the root system and extend it as far into the landscape as the customer will allow. These materials serve to suppress weed growth and turf competition; keep lawn mowers away from the fragile trunk; keep the soil and roots a bit cooler in summer than bare soil; and reduce evaporation from the soil. Over time, natural mulch materials will degrade and recycle nutrients back to the tree.
When well mulched, a newly planted tree will be surrounded by 2 to 3 inches of wood chips, pine needles, ground corncobs, stump grindings or some other naturally occurring material that begins 2 to 3 inches away from the trunk. An unfortunate recent trend in many parts of the country is the placement of a large quantity of mulch — often called a mulch volcano — around the base of the trunk. This is an unnatural mulch arrangement and can lead to collar/bole issues such as Armillaria root rot. On the other hand, if inexperienced lawn mower operators are working around the newly planted tree, they may run the machine into the volcano before hitting the trunk. However, the dumping of mulch on the trunk is to be avoided. Plastic sheeting is also an unnatural component, and though it blocks some light and therefore weed growth in the short run, it causes oxygen and water infiltration problems, which are difficult to recover from. Fabric sheeting is not much better in this context, and should be limited to locations such as slopes where it helps to keep mulch in place.
Providing water to new trees is essential, but it must be done in an appropriate manner. When determining the need for water, several factors must be considered. Probing the soil to check for moisture content is a good first step. Many tools can be used for this, including a piece of rebar, a cut-off golf club, a long screwdriver or a moisture probe. Secondly, keep the depth of the root system in mind. Newly planted trees will generally have a root system that is roughly the size of the root-ball. As the season progresses, new “sinker” roots will grow deeply, and “stabilizer” roots will grow horizontally. The moisture needs of both need to be accounted for.
Working with a landscape designer is helpful to the overall process of placing water near the root systems of trees. As much as possible, endeavor to separate trees from turf and water them according to their own needs. A good designer will understand this principle and aid in providing the correct amount of water for each component of the landscape.
Water should be applied slowly and steadily for newly planted trees. The use of soaker hoses and drip bags is a good approach for applying adequate water without runoff. The bottom line when watering is to keep the roots moist, not soggy or dry, and to water to the bottom of the root system plus 1 inch, and then stop. Any less and the bottom part of the roots won’t get enough and die, and any more than that is a waste.
Pruning should only be done when necessary. A new tree needs every leaf it has to photosynthesize and send carbohydrates and sugars to the rest of the tree. Removal of stems and leaves reduces the potential for the tree to get off to a good start. As such, pruning should be limited to correcting flaws in the tree’s structure, such as double leaders, broken branches, and crossing or rubbing stems. When pruning cuts are made, identify the branch bark ridge and the collar and use them as a guide, cutting just outside of the imaginary line between the two.
Trunk protection this fall
Depending on the circumstances and location of the tree in the landscape, it is advisable to place a durable material around the trunk to prevent rodent damage. Hardware cloth, poultry netting and PVC are good materials to use to help avoid injury from voles, mice and rabbits. In most situations, pushing the material 3 inches into the soil will be necessary, as well as covering the trunk surface. This trunk protection should be installed as the tree enters dormancy and then removed in spring as new growth appears.