Thrips on Viburnum
I had a severe bout of thrips on my viburnum over summer and seem to have managed it with spray. Is it likely it will return as the weather warms up? If so, what can I do now? Also will the frosts destroy existing insects?
Many viburnum species are very prone to thrips, particularly in warmer parts of the country and sheltered sections of gardens. There was a time 30-40 years ago when thrips, along with a number of insects, were destroyed by heavy frosts, however unfortunately this no longer appears to be the case.
Heavily infected shrubs like viburnum usually have considerable leaf fall during the winter months. Ensure all leaves are collected and removed from that part of the garden. As spring arrives, fertilise your viburnum with Daltons Premium Shrub and Tree Fertiliser to ensure the plant is growing strongly. This can provide some resistance to thrips.
You can continue to spray your viburnum with good quality horticultural oil. However, this may not eradiate the infection long term and the thrips can still return.
Finally, you may wish to remove the viburnum and plant an ornamental shrub that is not prone to thrips infections. This may sound extreme but there are many attractive shrubs that could more than adequately fill this position in your garden.