That branch is toast. Remove it and allow another shot of growth from elsewhere to replace it.

Dax

i was not aware the purple plums were grown for plums ... had one 20 years.. and the only time it ever fruited.. was the year before it died ...

see link

weird pic.. is half the tree green leafed??.. and half purple??? .. oh.. or is that dead part???

if a true fruit tree ... ignore link.. and go talk with the peeps in the fruit forum ... they are the real fruit experts..

ken

http://forums2.gardenweb.com/discussions/1658852/how-to-properly-prune-a-purple-leaf-plum

Tree does look droopy, try giving it a mulched, grass free area at least 3' across.

'Victoria' is an orchard plum, not a purple-leaved plum. Likelihood and abundance of fruit on the latter depends on which cultivar is planted, in addition to site conditions including local climate - dozens of kinds have been named over the years. One currently on the market called 'Spencer Hollywood'* is planted deliberately for dual purpose use, in fact it often fruits to the extent of branches breaking unless the plums are thinned when small.

*Usually listed as 'Hollywood' but that is an older, different introduction

Victoria is probably the UK's most popular plum variety.

Remove the dead branch and cut back well into healthy wood. Unlike apples and pears, plums and cherries should be pruned in the summer in the UK because of Silver Leaf Disease. When you cut away the dead portion look at the cross section of the branch. Is there a dark patch in the wood? The commonest reason for plums to fail here is Silver Leaf Disease so check for symptoms. Silver Leaf Disease

nice lawn.. and weed preventives or fert used???

i missed the cultivar name ... so much for that ...

ken

Thanks for your help/comments.

I did have the lawn treated with weedkilling herbicide and fed with a granular fertilizer earlier in the year by Greenthumb, a well know lawn maintenance company here in the UK. I was wondering myself whether they sprayed too near the tree as the grassed area probably goes over the top of the tree's roots. However, the same treatment was done last year and the tree looked a whole lot healthier, so it could be the dry Spring and Summer. That said, the tree now looks almost like it is wilting all the time. I have fed it recently with some plant food and that doesn't seem to have improved the situation.

I took off the bad branch (sawed it off) and the wood looks in good clean condition. All light beige/brown colour, no signs of disease.

Can you show a closer view of the foliage?

I will take a closer picture asap. Thanks