Assessing Winter Damage

tree frog

After a colder than normal winter, it’s time to assess winter damage in trees and shrubs.  For plants which normally would not have budded or leafed out by now, I suggest a wait and see approach.  For those that are evergreen, or should be showing signs of life, you can test it’s survival fairly easily.

The first category of plants are evergreens like rosemary and wormwood and camellia.  Although the leaves may have all died, the plant may still be alive.  Gently scrape off a bit of the outer bark and look for the green cambium layer.  The cambium layer is a thin layer of tissue under the bark that transports nutrients up the plant and provides cells for further growth.  If you see green (and it may be pale green), that stem is alive.

living cambian layer

Living cambian layer

If there is no green, give the twig a gentle bend and look for a place where the plant bends instead of being hard and brittle.  Go back to that point and check again.  The inner portions of the plant may be alive while the exterior portions, more exposed to the elements, are dead.  If so, prune back to the living tissue.  It may be that there is no sign of green.  In this case, the plant’s roots may be alive and it may grow back from the ground.  Give the plant a hard rejuvenation pruning all they way back to a stub, and wait.

dead cambium layer

It’s dead, Jim.

The second category of plants are deciduous shrubs which normally regrow on old wood.  These plants may have a very subtle cambium layer, one which is barely visible if at all.  Leave them be.  If you see the plant regrowing only from the roots, like this hydrangea, give it some time.  Go ahead and prune away the dead, brittle twigs once it’s clear it is not going to regrow from the existing wood.

hydrangea regrowth from roots

Top part is dead, but it’s coming back from the roots.