Plant Doctor Archive

Silvering rhododendrons

WE have rhododendrons in our garden. A few weeks ago we noticed some silvering leaves on one of them. What causes this?

YOUR rhodos are suffering from thrip damage. The silvering on the top of the leaf and brown spotting underneath is a clear sign, since the insects are very small and hard to see. Get a regular spray programme underway using Yates Mavrik, Orthene or Confidor. The spotting on the leaves could also be caused by over watering, wet feet, spray scorch or general stress.

Watch your watering and drainage over winter to ensure that root rot and fungal problems don't set in. Remember to water and spray early in the morning or late in the day so as not to burn the leaves.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.