A: This could be an indication of root decay but there are fungal pathogens which can also cause limb dieback. If possible, consider bringing me a clipping so I can better determine what might be the real problem. Limb dieback can be caused by over-watering, heavy mulching and over pruning. There are no chemical recommendations for this – just cultural changes:
- Boxwood plants are drought tolerant plants – consider removing or capping the irrigation. Watering twice a week can cause some serious issues.
- Mulch should not be touching the trunk of any tree or shrub and should be only 2 – 3 inches thick. Over time, mulch layers can build up and contribute to root problems. Heavy mulching should be removed. There should be an area directly around the trunk with nothing but soil and air.
- Consider allowing the shrubs to reach a slightly higher height to avoid over-pruning.