Plant Doctor Archive

Mulberry tree

I HAVE a gardening problem I'm hoping you can help me with. I have a mulberry tree (Morus nigra). It has been in about four years. (Admittedly, in the first two years I moved it three times, but it has been in the same place for the last two years.) The problem is that it gets what I think is leaf spot and, according to my book, needs to be treated with lime sulphur at varying rates. I didn't spray at leaf burst because you can't tell it has got leaf spot then, but I did spray with lime sulphur twice once the disease was evident. However that didn't help at all. Now all the leaves are affected (apart from the new emerging leaves) and the affected leaves eventually go black around the outside and drop off. I am now going to spray the new leaves with a general fungicide to see if that helps. Any suggestions? Should I spray each year as soon as the green buds start to appear?

The other questions I have with regard to my mulberry are:

1. When does the blossom appear and what do the flowers look like?
2. If we are lucky enough to get this mulberry to fruit, when does the fruit usually appear?
3. I am feeding the mulberry with general stuff e.g. blood and bone and Nitrophoska Blue. Is there anything else it prefers? Does it like any particular soil type? My soil is a bit heavy so I have planted the mulberry in a raised garden.

I would be grateful for any tips regarding this as we can't wait for the mulberry to fruit, as my partner is itching to make mulberry ice cream!

TRYING to figure out what a plant is suffering from and then treating it at the right time is sometimes a great art! It may pay for you to spray with Yates Greenguard or Fungus Fighter and see if that clears up your problem. You will have to spray over a couple of seasons to get the problem at different stages from bud burst to leaf fall. It may also pay to clean up the ground underneath the tree in case any fungal spores are over-wintering in the soil.

Mulberry flowers are quite inconspicuous. The trees are self fertile and have separate male and female flowers. The catkins are greenish in colour.

It can take a mulberry two to five years to fruit, so you shouldn't have too long to wait. The blood and bone fertilisers will be fine, otherwise you can liquid feed in the spring and summer with Yates Nitrosol.

Mulberries do not like a wet or boggy soil. They like free draining soil with some sun. If you prune, do this lightly as the mulberry has a tendency to bleed with sap easily. Good luck!

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.