Hi Alison,
Thanks for your question. Gosh that's pretty severe, isn't it? Very brown conifers and I'm glad you've raised this with the Garden Ninja community.
There are two reasons why conifers turn brown suddenly.
Pruning confiders too harshly causes them to go brown:
The first is cutting back conifers too harshly to older brown wood. Confiders do not regenerate new growth from old. That's why is so important to never trim back past the green growth. Once this happens there is no return other than hoping surrounding green growth can mask it.
Conifer Fungus - Pestalotiopsis dieback:
The second and more worrying issue is conifer fungus known as Pestalotiopsis which I think you have.
This is caused usually by stress on the confider which then allows the fungus to take hold. Particularly in wet conditions and if the conifer has suffered an attack of Cyprus aphid or has been damaged by hard pruning or severe winter frost.
There sadly is no real control method. If caught early you can prune out the infected growth but knowing that cutting back to old wood often leaves unsightly brown gaps.
The reason it has spread to the next one is that the fungus is airborne and will infect the rest along the way sadly.
I know it's not the news you want Alison but I'd dig them up and burn the infected ones. Then give the others a liquid feed to help give them a boost. Keep your eyes on the others and as soon as brown patches show snip them off.
Fingers crossed the others can be saved.
Lee Garden Ninja
Hi Alison,
Thanks for your question. Gosh that's pretty severe, isn't it? Very brown conifers and I'm glad you've raised this with the Garden Ninja community.
There are two reasons why conifers turn brown suddenly.
Pruning confiders too harshly causes them to go brown:
The first is cutting back conifers too harshly to older brown wood. Confiders do not regenerate new growth from old. That's why is so important to never trim back past the green growth. Once this happens there is no return other than hoping surrounding green growth can mask it.
Conifer Fungus - Pestalotiopsis dieback:
The second and more worrying issue is conifer fungus known as Pestalotiopsis which I think you have.
This is caused usually by stress on the confider which then allows the fungus to take hold. Particularly in wet conditions and if the conifer has suffered an attack of Cyprus aphid or has been damaged by hard pruning or severe winter frost.
There sadly is no real control method. If caught early you can prune out the infected growth but knowing that cutting back to old wood often leaves unsightly brown gaps.
The reason it has spread to the next one is that the fungus is airborne and will infect the rest along the way sadly.
I know it's not the news you want Alison but I'd dig them up and burn the infected ones. Then give the others a liquid feed to help give them a boost. Keep your eyes on the others and as soon as brown patches show snip them off.
Fingers crossed the others can be saved.
Lee Garden Ninja