Managing Leylands (without topping them)

[treeseer]

Diseases of Leyland Cypress Had to look up Cercospora Needle Blight

I did too, to confirm. NCSU puts out good info, but most of it's geared to the commercial growers. A more recent text says Passalora sp. is the pathogen, but no matter. We may spray with copper, but first there are a whole lot of dead needles to cliip off.

[daltontrees]

Zone 7 SE US which was mild and wet this summer, great conditions for Cercospora. The plan is to "CERCOSPORA BLIGHT ON FOLIAGE. Remove dead needles and twigs and branches. There is some hope for new interior foliage to form. The more light comes in, the greater the chance of adventitious growth.

 

Remove soil from stem tissue, dry the area, deeply aerate nearby soil, clean and heat any bleeding lesions, and amend the soil for structure with calcium fertilizer and beneficial microorganisms to help speed compartmentalization.

 

50% thinning proposed for crown above sight line. Reduce height only after assessment and approval." Client made it clear she was not in favour of topping. My past reductions of central leaders on leylands have not always met the objective of opening the center, as topping seems to spur the kind of dense growth that it was supposed to get rid of.

 

In my limited experience of these things, putting lime anywhere near the soil of Leylandii can be disastrous. Not only do they like and create their own acidity, they actively dislike alkalinity and it messes up a very delicate balance of bacteria and fungi around the base that collectively buld up a steady mild toxicity and acidity that maximise the growth conditions for Lelandii.

 

My standard action for improving light internally wher there is a lot of dead foliage is not to remove branches or twigs but to strip them bare by pulling though your hand with a thick leather glove on. If it doesn't want to fall off it won't, if it does the wood will already have compartmentalised and is best left alone in situ.

 

I have never diagnosed Cercospora, but I would be tempted to put tarps under the canopies before removing dead material, then drag the tarps out and burn the dry stuff. I'd probably be tempted to blow the grould clear of debris first, and butrn that too, then mulch the whole under-canopy with conifer mulch afterwards.

 

Just my random thoughts, based on fairly non-systematic observatrions of past successes and failures.

[treeseer]

Just my random thoughts, based on fairly non-systematic observatrions of past successes and failures.

 

Good thoughts thanks. Any concentrated fert would be heavily buffered by blending with compost.