Planting a tree during the summer is possible, but it is not the ideal time for the tree’s health. While spring and fall offer optimal conditions, successful summer planting demands extra vigilance and a precise commitment to care. Establishing a new tree in the heat involves understanding the biological stress factors and strictly implementing a prescriptive planting and watering regimen.
The Immediate Risks of Summer Planting
Summer heat and dry air create a high-stress environment for a newly transplanted tree, primarily causing a disruption in water balance. The most immediate threat is transpiration stress, where the leaves lose water vapor faster than the roots can absorb it from the soil. This rapid water loss forces the tree to shed leaves or enter a state of summer dormancy to conserve moisture, diverting energy away from establishing new roots.
This environmental pressure is compounded by root shock, which is the inability of the disturbed root system to function effectively. Trees that are balled-and-burlapped (B&B) can lose up to 95 percent of their root mass during harvest, leaving a severely compromised system to support a full canopy of leaves. Container-grown trees retain their entire root system, but their former potting mix can dry out faster than the surrounding native soil, increasing their vulnerability to water stress.
Critical Site Preparation and Installation
Mitigating summer stress begins with the planting hole, which should be two to three times wider than the root ball but no deeper. This width provides loosened soil for new roots to easily grow outward, as most tree roots grow horizontally. The goal is to set the tree so the root flare—the point where the trunk widens at the base—is visible and slightly above the finished grade, accounting for settling.
Planting should be scheduled for the coolest part of the day, preferably in the late evening, allowing the tree maximum nighttime hours to recover before facing the next day’s sun. Container-grown roots must be gently loosened or scored with a knife to interrupt any circling patterns, encouraging outward growth into the new soil. Immediately after planting, apply a 2- to 4-inch layer of organic mulch, such as wood chips, over the entire planting area to cool the soil and reduce water evaporation. Ensure the mulch is pulled back a few inches from the trunk to prevent moisture retention against the bark, which can cause decay.
Establishing a Summer Watering Schedule
A precise watering schedule is the single most important factor for summer survival and must prioritize deep, slow saturation over frequent, shallow sprinkles. Newly planted trees require frequent watering initially, often daily for the first week or two, then shifting to every two to three days for the next three to four months. The tree needs approximately 2 to 3 gallons of water per inch of its trunk diameter with each application to thoroughly soak the root ball and the surrounding soil.
To prevent runoff and ensure the water penetrates the root zone, create a temporary soil berm, or small circular wall, around the perimeter of the planting hole. This barrier acts as a reservoir, allowing water to soak in slowly. The most reliable method for checking soil moisture is to use a trowel or your finger to dig a few inches down into the soil near the root ball. If the soil feels dry at that depth, the tree needs water; if it is cool and damp, delay the next application.
Comparing Summer vs. Ideal Planting Times
While summer planting is feasible with high maintenance, the preferred seasons for tree establishment are fall and early spring. These periods naturally reduce the risk of transplant shock by providing cooler air temperatures, which lowers the water demand on the leaves.
Fall planting offers a significant advantage, as the air cools faster than the soil. This combination of warm soil and cool air promotes robust root growth while the tree’s above-ground growth slows down in preparation for dormancy. The tree can dedicate its energy reserves to developing an extensive root network before the demands of spring leaf-out begin. Waiting until the cooler temperatures of early fall will significantly increase the chances of successful, long-term establishment.