Successful Installation Techniques for Woody Plants

Most people believe that installing a tree or shrub is easy, wondering “how hard can it be to stick a plant in the ground?” While transplanting is simple once you know the proper techniques, it is a little more complicated than just digging a hole and inserting a plant.

Common Myths

Transplanting techniques are cloaked in a number of myths, many of them widespread and long-held. Many recommended techniques come from agricultural settings; while these practices work fine there, they are not good for urban or non-agricultural areas. Common myths include:

• The root ball should not be disturbed, as this will traumatize the plant
• Adding rich, well-drained organic matter to the planting hole is essential to give the plant a head start
• The plant crown should be pruned to make up for root loss

The Reality

While these practices may seem intuitive and proper, they can actually harm the plant. Unobstructed roots grow horizontally. Containerized roots, however, often circle around the container (due to lack of growing room) or develop kinks or knees. 

Unless the problem roots are removed or fixed at transplanting, the problems will worsen, reducing plant stability and increasing the likelihood of plant death. 

Organic amendments create soil interfaces that roots are unlikely to grow across; instead of growing outward, the roots simply circle around the amended planting hole soil. 

Organic matter also decomposes, often quite quickly, leading to sunken planting holes. If shoot and leaf material is pruned away while transplanting, the plant will focus its energies on replacing the lost material, rather than growing roots and establishing it in its new location.

Correct Techniques

Properly installing a plant takes time, but will save time, energy, and resources in the long run. By utilizing the following techniques, you can improve the odds that your plant will be healthy, establish quickly, and require less aftercare than a poorly installed specimen.

Preparing the Site

• Plan ahead! Choose a site that is sufficiently large and away from utilities and other potential problems
• Dig a planting hole twice as wide and the same depth as the root ball; this will allow you to spread the roots out without crowding or damaging them
• Remove rocks, roots, weeds, and other debris from the planting hole
• Build a mound of soil in the bottom of the planting hole

Preparing the Plants

• Protect and harden off plant materials prior to transplanting
• Store bare root material in moist sawdust or soil to keep roots from drying out
• Fall transplanting is best in the Pacific Northwest; plants installed in the spring will require more irrigation
• Remove any burlap, wire, tags, or other foreign materials that could limit plant growth or damage the plant
• Remove existing soil from containerized plants
• Prune or straighten circling, girdling, or kinked roots; shorten excessively long roots
• Prune only dead, damaged, or diseased shoots - do not top prune
• Place the plant atop the soil mound and spread the roots out evenly
• Orient the plant so the root-shoot interface is at or slightly above the soil surface

Finishing Up

• Backfill only with the native soil that was removed from the hole – do not add fertilizers, organic matter, rocks, or other amendments
• Water the plant well to settle the soil; if holes appear, fill them with native soil
• Top-dress the root zone with a thick layer of organic mulch – wood chips work best – but keep it 1-2 inches from the plant trunk to prevent trunk rot or moisture damage

• Fertilize only with needed nutrients – nitrogen is typically the only deficient nutrient in the Pacific Northwest
• Stake only if necessary; stakes should be low (bottom 2/3 of the plant), loose, and removed after one growing season