It's nearly prime transplanting time, but before you start digging, make sure you know what you're doing because trees can be difficult — and expensive — to replace. And the older and more established they are, with large root systems, the more care that needs to be taken. And moving large trees is best left to professionals.
Deciduous trees — those that drop their leaves in autumn — are better candidates for transplanting than evergreens, which more readily go into transplant shock. Be sure to employ these tips about timing and technique to lower the stress on the plant and raise your chance of success.
Transplanting deciduous trees
Wait until deciduous trees have lost their leaves and entered dormancy, typically in mid- to late-autumn or early winter.
Dig up the tree when you plan to move it — not a day before. Having a planting hole prepared will go a long way toward reducing the chances of transplant shock, as it minimizes the time roots are exposed.
Make sure the new spot you choose for the tree takes into account the requirements of your specific tree, such as full sun or part shade, and is protected from strong winds and has well-draining soil.
Measure the diameter of the trunk about six inches above the soil line; multiply that number by four to five, then double that to determine the size of the hole you will dig around the tree to remove it. You’ll double that number again to determine the size of the hole where the tree will be transplanted.
For a trunk that is 2 inches in diameter, for example, the hole for the transplanted tree would be 8 to 10 inches times 4; that is, a hole 32 to 40 inches in diameter. Dig the new hole first. Dig to a depth of 10 inches, adjusting as needed when planting.
To uproot the same size tree, you’d dig a hole that encircles the trunk by 8 to 10 inches all around. Take care to dig deeply — maybe 10 or so inches depending on the type, size and age of the tree — to retain most, if not all, of the root system.
When you've freed the roots, place the tree on a large square sheet of burlap; secure the burlap around the roots with twine, fashioning a pouch. This will keep the roots intact and retain soil.
Don't drag the tree. Place it on a hand truck or in a wheelbarrow (it will likely be heavy) to wheel it to the new home you’ve prepared. Unwrap the roots and discard the burlap and twine.
Place the tree in the hole, adjusting its depth if necessary so that the top of the root ball is slightly higher than in its old home. This allows for settling.
Holding the tree steady (you'll need help with this) backfill the hole with soil, stopping periodically to tamp it down, and ensure the tree remains straight. When the roots are half covered, water the soil in the hole to eliminate air pockets, then continue filling and firming. To give the tree a nutritional boost and optimize drainage, incorporate a generous amount of compost into the backfill.
Slowly apply about 2 gallons of water to the soil, then apply 2 to 3 inches of mulch around the tree, beginning two inches from the trunk (applying mulch closer to the tree invites insects and other pests, and risks rot.)
Do not apply fertilizer.
Water newly planted trees regularly until frost, then resume watering in spring. Continue this regimen for the entire first growing season, again straight through frost, when roots should be fully established.
Both needled and broadleaf evergreens are best transplanted in early spring, just after the ground has thawed, but they can be moved in August or September. Moving any later shortens the window trees have to establish a root system sufficient to survive winter. Regardless, moving evergreens can be risky, so proceed with caution and do so only if you can accept failure.
Instead of measuring the diameter of the trunk, as for deciduous trees, you'll need to measure the spread of your evergreen's branches to determine how far the roots extend and plan the size of the new planting hole. If the branches on each side of the tree extend 12 inches, dig a hole 9 inches deep and 12 inches wide. If the branch spread is 3 feet, the roots can be assumed to stretch roughly 16 inches wide and 12 inches deep. Trees with a 5-foot branch spread have roots that are roughly 22 inches wide and 15 inches deep. Prepare a new hole before digging up the tree to minimize the time roots are exposed.
Tie up branches to protect them from being broken during the move; this will also help you see what you're doing and improve access to the soil around the tree. Taking the previous measurements into account, dig up the tree. If you notice roots extend farther or deeper, you can safely cut them off at the recommended size, as that would be sufficient to support a tree of that size.
Place the uprooted tree on a square of burlap (as instructed for deciduous trees) and carry or wheel the tree to the prepared planting hole. Place the tree in the hole, ensuring the top of the root ball is at the same depth it was previously; hold it straight and backfill with removed soil (preferably mixed with compost), tamping as you go to firm the soil and remove air pockets, and watering midway during planting.
Water well, then apply 2 to 3 inches of mulch over the entire root ball, beginning two inches from the trunk. Keep soil moist, but never soggy, until frost.
Evergreens are so named because they don't enter complete dormancy, as deciduous trees do, but remain green year-round. This means they also require water over winter. This is especially important for newly planted or transplanted trees, so keep a hose connected for water during extended dry spells in the absence of snow cover.