Hi. I planted 12 Sweet Viburnum in Nov last year. I'm near Orlando, FL Zone 9B.

The plants have been growing well and are on a drip irrigation system in full sun in our south facing garden.

However a couple of months ago a noticed the brown leaf damage shown in the photos. I cut off the affected leaves, but it has come back just as strongly.

This is affecting all 12 plants to some extent.

Is this perhaps the plant just struggling in its early life with the heat of the summer sun, or is it something more sinister?

Advice much appreciated.