anyone got any experience of a sick Mahonia?

[ameliagrey]

I have had a lovely tall mahonia- think it's Charity- in a north facing corner for around 12 years- it's about ten feet high.

last year though half of it looked dead. the leaves fell off and the branches are still bare.

It's kind of "Y" shaped, so to cut off one side would look very odd.

I don't know why it is sickly- it gets some morning sun, the roots go under a fence alongside the neighbour, but it was doing really well.

I know they are usually hardy so has anyone got any ideas what to do with it now?

Prune out the dead wood. It may make it an odd shape, but new branches will sprout. If you don't, and it has a disease, the disease will spread down into the rest of the tree. Or even if it the disease doesn't spread, dead wood attracts fungus and other kinds of rot which won't do the tree's general health any good at all.

Thanks. I just can't work out why it's sickly- I have other mahonias in the garden and they are thriving- too much so.

You mention that the roots go under the fence; I wonder whether the neighbours damaged some roots or applied weedkiller on their plot which could have been affecting your plant. I agree with the pruning out of dead/diseased wood but would wait until flowering has finished, roughly April time.

Mahonias can also be affected by rust which shows as mottled leaves and some defoliation. If you find yours suffers from rust I would spray in Spring and prune a few weeks later.