A common problem that is appearing with many older Cypress hedges and windbreaks is dieback.
This is a fungal disease (Seiridium) that has decimated a range of Cypress in Australia and around the world.
It begins with any part of the tree that is damaged through storm damage that causes limb shear, pruning insects holes and even cracks in the bark. The fungal spores are spread in a number of ways including by wind.
Signs of Cypress Canker
One sign of infection is resin or sap flow along the trunk or branches, this leads to dieback of the foliage and then the death of the tree.
The problem is exacerbated by other stress factors on the tree including drought followed by excessive rainfall and soil moisture.
A number of treatment have been tried however at the time of writing none have proved to be very effective.
Some species are less susceptible to canker, however as far as we can determine none of the exotic species are immune.
A few species regarded as less susceptible are :
- Arizona Cypress (Cupressus arizonica) which will reach around 10 – 15 metres in height.
- Bhutan Cypress (Cupressus torulosa) (40 – 50 metres)
- Western Red Cedar (Thuja plicata) ( 6- metres plus)
- Thuja occidentalis ( 15 metres depending on cultivar and conditions)
- Juniperus virginiana (To 20 metres – often less depending on soil and climate)