The New Zealand Plant Conservation Network

Dying five-finger tree. A beautiful five finger has gracefully sheltered our canterbury coastal property for 10+ years. It has always been mature since we've owned it, and we've had no previous trouble. A few weeks ago, it began wilting. Thinking it could be a lack of water, it was watered regularly with no improvement. The leaves are dying branch by branch, turning black. I've added worm castings to the soil, with no improvement. Any suggestions on what is causing this or how to stop this? About a year ago, my neighbour also lost his five-finger, and I see another one down the road is doing the same. We can't help but wonder if the soil changes from the earthquake have anything to do with this....

Hello. You could be right. A true diagnosis is pretty much impossible without sending a sample of the tree away for testing. I would guess that these trees are slowly dying due to either a fungal or bacterial infection. As you say drainage patterns and other soil characteristics may have changed in the earthquakes and these have caused the trees to be stressed, in turn causing them to be susceptible to infection, which is now causing them to die off. The trees could also be stressed for some other reason. Five-Finger tress are pretty resilient to very dry conditions. What I can say is that you probably won't be able to help your tree and may need to think about replacing it in the near future, as all the dying Pseudopanax's that I have seen seem to die rather quickly and don't often recover. Also note that if it is a water mould (Phytothora) that is killing your tree you may have to plant a new species that is not susceptible to this as it tends to hang around in the soil for a while.

Hi J. Unfortunately it could be caused by several things - it sounds most like a fungal infestation of the roots, but it could be changes to subsurface water levels following the earthquake (wet feet) or 5-finger is short-lived (at a guess it could be as short as 30 years for some individuals). If it is fungus then copper sulphate solution watered around the base may just save it but usually there is little that can be done.