How to Perform a Scratch Test for Trees & Woody Shrubs

How to Perform a Scratch Test for Trees & Woody Shrubs

Reliable Viability Check for Customers & Crews

The scratch test is the fastest way to determine whether a tree or woody shrub is alive after a hard freeze.

How to Perform It

1. Use your fingernail or a small blade to gently scratch away a thin layer of bark.
2. Look at the cambium layer beneath:
   • Green & moist → the plant is alive
   • Brown/gray & dry → the tissue is dead
3. Test multiple points:
   • Near tip of the branch
   • Mid-branch
   • Main trunk

How to Interpret the Results

• Green at branch tips: Damage is cosmetic only.
• Green only to middle branch: Tip dieback; prune once warm.
• Dead several inches down: Significant freeze damage; monitor for 4–8 weeks.
• Dead down to the trunk or crown softness: Likely non-recoverable.

Best Trees & Shrubs to Apply This To

Crape Myrtle, Loquat, Olive, Magnolia (all cultivars), Elm, River Birch, Cedar, Oaks, Gardenia, Loropetalum, Viburnum, Hollies, Camellias, and other woody ornamentals.

When to Scratch Test

• First test: 3–4 weeks after freeze
• Follow-up: 6–8 weeks
• Final determination: Spring leaf-out (deciduous species)