Montana State University

Northern Gardening Tips: Tips for spring tree and shrub planting

May 15, 2006 -- By Cheryl Moore-Gough, Montana State University Extension Horticulture specialist.

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BOZEMAN -- If the landscaping bug has bit you, chances are you're eyeing the trees and shrubs at your local nursery. These tips can help give new plants a good start.

Timing:
Bare-root trees and shrubs should be planted when they are dormant, so if the trees have started to leaf out in your part of the state, it's too late to plant bare-root stock. Unless your local nurseryman has extended the dormant phase by refrigerating bare root stock, head for the containers and balled and burlapped stock. Balled and burlapped or containerized plants can be transplanted almost any time of the year, but it's best to do it in the spring or fall and avoid the summer heat.

Preparation:
Dig a hole about twice as wide as the size of the root ball and about as deep, or very slightly less deep, than the ball. In heavy soils, roughen the compacted soil along the sides of the hole with the edge of the spade so that water will drain more freely and root growth will not be restricted.

Don't put gravel or stones in the bottom of the hole.

Don't put granular fertilizer, manure, compost, hormones, or vitamin supplements in the planting hole. Dry fertilizers may burn emerging roots and organic matter may delay roots from spreading.

Planting:
For bare root stock, make a small mound in the center of the hole and spread the roots out evenly over it.

For balled and burlapped stock, set the tree in the hole and remove the ties that hold the burlap to the root crown (at the top of the ball, where the roots join the trunk). Remove the materials if it's plastic or synthetic. Natural burlap does not have to be completely removed. After removing the ties, tuck the burlap back against the sides of the ball so that no burlap is exposed to the air after the hole is backfilled. Inspect the root ball, taking care not to damage the roots, and gently untangle any circling roots.

For container stock, lay the plant on its side near the hole and thump the bottom and sides until the roots are loosed, then gently remove the root ball from the container. If the roots are growing around the ball (circling roots), slice through them and into the ball in several places around the root system. Cutting them encourages lateral branching and production of new roots.

Work quickly, since exposed roots dry rapidly. Never wrap an especially long root around the hole. Instead, cut it to fit easily.

Don't set plants too deeply in the hole. Set them so that the top of the root crown is about a half-inch above the soil line at planting. Remember, the soil beneath them will settle a bit.

Planting depth differs for fruit trees grafted to size-controlling stocks. Set them so that the graft union stands about 2 inches above the final soil line. Grafted rose bushes should be set so that the graft union lies a few inches below the final soil line.

Backfill the hole with soil that came out of it, putting the topsoil in first and the subsoil second. When the hole is half full, gently tamp it down and flood it with water. When that has drained, replace the remaining soil, tamping and flooding it again. This helps to collapse air pockets and establish a good soil-to-root contact.

After planting:
Create a dike and basin around the tree to hold water. Water again, deeply, right after planting. In the fall, kick a hole in the basin so ice won't form and damage the crown and roots of the tree.

Mulch in a 3-foot diameter circle around the tree right after planting. This helps keep the soil moist and reduces weed growth and competition with the tree. A wood chip or bark mulch is effective and attractive. You may want to underlay this with landscape fabric to prevent weed growth.

Remove all plastic and metal tags right after planting to prevent girdling the tree.

Care of new trees:
Large trees in windy locations may need support until their roots spread into the surrounding soil. A single stake and guy wire may suffice for smaller trees; larger trees may need three guy wires for support. Be sure to allow for some movement in the wind. Staking trees too rigidly can weaken them by slowing the development of woody tissue. Remove all support (guy wires, stakes, etc.) within a year of planting.

Trees may need three to five years to recover fully and become established. During that time they are especially vulnerable to heat and water stress. Keep them well-watered, wetting the soil to a depth of 10 to 12 inches at each watering.

Plastic guards, especially white ones, protect the trunks of trees from rodents and winter sunscald. This is particularly a problem on young trees and dark-barked trees and can lead to further damage. Apply the guards in October and remove them in April, repeating for at least eight years after planting. If rodents are a problem, you can construct a permanent rodent guard at the base of the tree.

Evergreens and shrubs are not particularly subject to sunscald, but drying is still a concern. To help prevent this in young trees, especially evergreens, protect them from western exposure by spraying them with an anti-transpirant or by constructing a wind/sun shade on their west side.

After the leaves drop in fall, give the plants one inch of water per week until the soil freezes.

You should not have to fertilize for the first year after planting.

You can prune broken branches, crossing branches and branches pointing toward the inside of the tree at planting. Otherwise, most trees and shrubs need little pruning for the first two or three years after planting. Trees grown for their edible fruit are a special case. Their training should begin in the second year.

The publication, "Trees and Shrubs in Montana" is available for free download at http://www.montana.edu/wwwpb/pubs/2B323.html. For more publications and information on growing trees and shrubs in Montana, contact your county or reservation MSU Extension office, or visit http://www.msuextension.org.

A high resolution photo of Cheryl Moore-Gough, a high-resolution color graphic and a black-and-white graphic of the garden tip art is available on the Web at: http://www.montana.edu/cpa/extension/gardening/graphics.html

Contact: Cheryl Moore-Gough, MSU Plant Sciences and Plant Pathology, (406) 994-6523 hort@montana.edu