When to Winter washing fruit trees

Best to do the winter tree wash now, while it’s dry and the tree is fully dormant, even if it’s cold.

Why now is best

• Dormancy is key – once the leaves have fallen, pests (aphid eggs, red spider mite eggs, scale insects) are tucked up deep in the bark cracks. Winter wash works best at this stage.
• Cold doesn’t matter – the wash kills eggs on contact; insects don’t need to be active.
• Dry conditions matter more than warmth – rain within 24 hours can dilute or wash the treatment off before it’s fully effective.

Devon-specific advice 

Because Devon is often milder but wetter:

• Take advantage of any dry spell between December and February
• Apply on a still, dry day
• Avoid:
  • Frosty days where it stays frozen all day
  • Rain forecast within the next 24 hours

If you wait for warmer weather, you often end up chasing dry days – and by then some pests may already be waking up.

Best practice

• Apply Vitax Winter Tree Wash with a jet or pressure spray
• Really soak:
  • Trunk
  • Main branches
  • Forks and crevices in the bark
• One thorough application is usually enough, but a second wash 2–3 weeks later can be worthwhile if pest pressure was high last year.

You can read more detailed guidance here:
 https://gardenadvice.co.uk/gardening-tips/apple-tree-care-and-general-pruning-rules/