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Tree Selection and Planting

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A guide for choosing and planting native trees. 

Tree Selection

Tree selection should be based on the site conditions – soil, hydrology, sun exposure, and plant hardiness zone. Traditionally, the recommendation has been to recreate native plant communities, selecting trees appropriate for various plant communities found in a region. However, that strategy may need to change in light of climate change, which can make certain tree species less resilient by shifting plant hardiness zones and changing precipitation and temperature patterns. More information on how climate change may affect tree species selection can be found in Climate Change. See Native Plant Reccomendations for help with species selection. 

Monitoring Suggestions

  • Track survival rate of new plantings
  • Track long-term changes in precipitation and temperature or plant hardiness zones for plant suitability

Planting Trees

Use the following guidelines for planting balled and burlapped (B&B), containerized, and bare-root trees. Videos are also available on the Pennsylvania Horticultural Society website. 

  • Use only native tree species (ordinary, wild-type species rather than hybrids or cultivars) appropriate to site conditions (see Native Plant Reccomendations). Ideally, they should be grown from local seeds or cuttings unless intentionally sourcing from warmer climates to address climate change.
  • All plants should be nursery grown in accordance with the American Standards for Nursery Stock, latest edition.
  • All plants should be typical of their species or variety and should have a normal habit of growth (avoid variegated-, yellow-, or red-leafed, dwarf, “weeping,” or other atypical selections). They should be sound, healthy and vigorous, well branched, and have dense foliage. They should be free of disease and insect pests, eggs, or larvae. They should have healthy, well-developed root systems.
  • All plants should be balled and burlapped (B&B), containerized, or properly handled bare-root seedlings or saplings.

Balled and Burlapped Tree Planting. Width of planting hole is 2-3 times root ball diameter. Set ball on firmly packed soil to prevent settling. Gently pack backfill around root ball base. Use water to settle remaining backfill or tamp lightly. Apply a 2-4 inch layer of mulch, keeping mulch away from trunk base and root collar. If staking is necessary, use 1 or 2 stakes with separate flexible ties. Stakes and ties should remain no longer than 1 year. Be sure the root collar is exposed.

NDSU Extension Service, North Dakota State University.
  • Unless protected from deer browsing, trees should be 6-8 feet tall at planting to help ensure that they can outcompete introduced invasive plants and so that some of their foliage and the terminal bud(s) of the central branch (leader) are above the reach of browsing deer. Bare-root trees are less expensive than container trees but their survival rates are lower, although bare-root trees now are often shipped with their roots coated in a hydrogel—a synthetic water-absorbing compound—to protect them from desiccation. Container trees are easier to plant and have a much greater survival rate than bare-root trees, especially if soil conditions in the planting area become dry.
  • Bare-root stock must be planted in fall or early spring, preferably when most deciduous trees are leafless or nearly so; using container or balled and burlapped trees extends the planting season by several weeks at both times.

Bare-Root Tree Planting. Step 1. Before planting, soak overnight but not over 24 hours. Dig a hole wider but at same depth as root length. Step 2. Prune damaged or weak roots and branches. Set on firm mound of good topsoil, spread roots. Step 3. Plant at the same depth or slightly above the level grown in the nursery. Fill with good topsoil. Tamp firm. Fill basin with water. Add topsoil to reshape basin. Step 4. Small trees, 8 inches tall or less, usually do not need support. Support larger trees if necessary for one growing season only (see text for details).

NDSU Extension Service, North Dakota State University.
 
  • Roots of all transplant plants should be adequately protected from sun, drying winds, and frost. The roots of bare-root seedlings should be kept constantly moist until planting.
  • Forest gaps and afforestation areas should be planted with trees on a 10-foot × 10-foot spacing; if resources are limited, spacing can be increased to as much as 15 feet × 15 feet. Spacing can also be increased (up to 20 feet × 20 feet) if resources allow for the purchase of larger plants and protection from deer browsing and rubbing. Plantings should be protected from deer damage with fencing, tree shelters, flexible tree guards, or staked wire mesh cylinders 5 feet tall. Fencing and tree shelters prevent deer from browsing leaves and buds. The tree wraps and stakes minimize damage to the bark and cambium layer of young trees caused by antler rubbing. The wraps should cover the trunk from 1-5 feet above the ground. The stakes should be placed in the ground close to, and on opposite sides of, the trunks. They can be made of wood, metal, or other rigid materials (including bamboo) and should be at least 5 feet tall (above ground level).
  • The planting hole should be 2-3 times as wide as the diameter of the root ball or spread of roots, but not deeper than the root ball. As necessary, mound soil in the hole so that the top of the plant’s root ball will be at or slightly above ground level.
  • All burlap, twine, and wire should be removed from at least the upper half of the ball and laid flat in the hole or cut away completely after the plant has been set in place. It is essential to completely remove all synthetic string and fabric from around the root ball (natural fiber burlap will decompose in time).
  • Backfill with soil and lightly tamp the soil surface. Strictly avoid piling any soil (or mulch) against the base of the stem where it meets the top of the root; this can cause decline or death of planted trees and shrubs.
  • If space permits, temporarily mound soil into a collar 4-5 inches high surrounding the perimeter of the root ball to help retain water until the tree is established.
  • If planting on a slope, mound the soil downslope to level the ground above the root ball and help keep runoff from washing soil away.
  • Mulching the soil surface of the backfilled planting hole with wood chips, hardwood mulch, or biodegradable landscape fabric can help retain soil moisture in the rooting zone, reduce soil loss to runoff erosion, and reduce competition from colonizing plants until roots become established. Dyed mulch should not be used. It is essential to avoid placing any mulch in contact with the stem. The so-called “volcano” practice of piling mulch against the stem promotes pathogenic fungal growth, resulting in the decline or death of planted trees and shrubs.
  • Watering at the time of planting is recommended, especially if the plant is not dormant or planted during warm or dry weather. If water is easily accessible, water all plants at the time of planting to help remove air pockets from backfilled soil. Ideally, the planting hole should be backfilled ¾ full with soil, watered well, filled the rest of the way with soil after the water has been absorbed, rewatered, and tamped lightly. Monitor the plantings for at least the first summer, watering them if conditions become dry. A little maintenance goes a long way. If available, put a layer of mulch 2-3 inches thick over the planting area, but no closer than 2 inches from planted trees’ trunks. Avoid large mounds of mulch around the trunk.
  • Stakes and flexible ties should not be used unless the tree is planted with a loose root ball or later found to be displaced. If they are required, use one or two hardwood stakes, no less than 2 inches × 2 inches across, driven into the ground outside the root ball. The stakes should be tall enough to provide the firm support necessary for proper root development, but not too tall to permit the tree to flex in the wind. The stakes should all be the same height for uniform support. All stakes and ties should be removed from the tree after one year.
  • Heavy equipment should be used only in extreme situations, for instance, when large trees are transplanted using a tractor-mounted tree spade. If it is necessary to use heavy equipment in a planted area, protect trees and shrubs by staying as far away as possible (at least outside the drip line) to prevent soil compaction and trunk scarring.
  • Mow or hand-trim as necessary within the drip line to maintain any herbaceous vegetation at a height no greater than 6 inches until areas are permanently reestablished with new plantings. If trees are planted in fields covered by sod (old pasture, meadow), it is best to kill the grass in the planting area before planting trees. This is especially important for small seedlings which have difficulty competing with sod grasses for water and nutrients. If spraying is needed after planting, tree shelters can protect seedlings from herbicides.

Monitoring Suggestions

  • Track survival rate of new plantings
  • Assess prevalence of invasive plants
  • Assess for damage by wildlife

Outside Resources

Gardening with PHS: Tree Planting [Fact Sheet] Pennsylvania Horticultural Society. (phsonline.org/uploads/attachments/ckpipzb307bvsmiraxenax4ah-2021fs-tree-planting-rd1rd2.pdf, as of 2024).