Roses are the shrubs most commonly seen as standards.

How to Train Shrubs to Tree Form

by Patricia H. Reed

Purchasing a tree-form shrub, or a "standard" in landscaping lingo, can be pricey, because you're paying for several seasons of training as well as the plant. You can, however, get the same effect for free with a few well-placed cuts when you begin with a shrub already on your property. Whether you need to renovate an old established evergreen or want an interesting form for a summer-flowering deciduous plant, nearly any shrub that responds well to pruning can be pruned into tree form. No matter when -- or if -- your shrub blooms, begin a tree-form transformation in late winter before new growth begins.

1 Brush any dirt or debris from the blades of your pruning tools before you begin pruning your shrub. Spray the blades with household antiseptic cleaner and wipe them dry with paper towels to eliminate any lingering fungal or disease spores from the last plants you pruned.

2 Select one to three main shoots on your shrub to serve as your new tree's trunk or trunks. Looking at the framework of your shrub should tell you whether it would be best as a single-trunk or multitrunk tree. Single-trunk standards can require more maintenance if the shrub naturally sends out a lot of shoots from the ground.

3 Cut off all the extra shoots or stems at ground level with a pruning saw or loppers, depending on how thick they are.

4 Remove all limbs or shoots from the bottom one-third of the new trunks, cutting 1/4 to 1/2 inch from where they meet the trunk to avoid cutting into the branch collar. The branch collar is a slight ridge on the trunk at the base of a stem that is filled with growth cells that help the pruning wounds heal over.

5 Cut back any crossing branches or branches extending from the silhouette of the tree with loppers or pruners, cutting them off where they meet another stem or the trunk.

6 Limb up -- the term for cutting off entire branches to create a tree-form shrub -- any additional branches above the bottom third of the trunk or trunks until the bottom limbs are at the height you prefer, the following year before new growth begins.

7 Clip off shoots at ground level or low on the trunk any time you see them.

Items you will need

  • Bypass pruners
  • Loppers
  • Pruning saw
  • Soft-bristle brush
  • Household antiseptic cleaner
  • Paper towels

Tips

  • Cut out one-third of the oldest, longest branches each year on flowering shrubs that bloom on new wood to encourage plenty of flowers each season.
  • Use the new space under your tree-form shrub for perennials or annuals.
  • Use bypass pruners for branches less than 1/2 inch in diameter, loppers for those from 1/2 inch to 1 1/2 inches, and a pruning saw for larger limbs.

Warning

  • Old evergreens that need limbing up may have branches large enough -- more than 2 inches in diameter -- to require a three-point cut to safely remove them. Make the first cut 12 inches from the trunk, cutting one-third of the way through the branch from its underside toward the top. The second cut is 1 to 2 inches past the first cut, moving toward the tip of the branch, and is made from the top of the branch down. The third cut removes the stub, just above the branch collar.

Photo Credits

  • David De Lossy/Valueline/Getty Images