You haven't said how large the planting area is, but it doesn't look very big, certainly not big enough for much. If the plum tree has only been in less than two years, nothing should be planted within a foot of it anyway - and after two years, you'll still need a foot all round that isn't planted because of the roots. In such a tiny planting space, maybe a couple of Skimmia 'Magic Marlot' either side - they're dwarf shrubs and don't mind shade. I would have suggested Mahonia aquifolium, but just one will get up to five feet wide.

Euonymus fortunii stay quite compact and are brightly
variegated. The flowers are totally inconspicuous but the shrubs do well in shade and are the same all year.They will stand clipping back if they get wider than you want.Take Bamboo's advice re leaving space round the tree - you will need a bigger bed if you want to plant under the tree.
You can plant bulbs within the bare area though.

But before planting anything permanent I would honestly wait until the autumn and move the tree further from the fence. Remember its going to be a tree. In that position three quarters of the branches will overhang your neighbours gardens so you would lose most of the fruit and your neighbours would be within their legal rights to cut off any overhanging branches.

Thanks a lot for all your advice. I think i am going to go with the Skimmia Magic Malot. I already have a Euonymus fortunii in this patch. I will send you pics when i am finished. The tree is more away from the fence than it looks in the pic. Thats the farthest i can go as its not a very big garden. Thank you again :)

Nevertheless I stand by my advice. How far is it actually from the fence? Can't be more than 2 feet? Unless it is a dwarf tree you risk arguments with neighbours when it gets bigger. Do you know what sort of stock its on? Fruit trees can have different rooting stocks which affect how big they grow. Did the label say how big the tree would grow?I don't want to depress you, just trying to save you difficulties later. If you really want a large tree in your size garden the best place would be well out into the lawn.

hi there Steragram . Please see link for details of my tree: http://www.amazon.co.uk/gp/product/B00FJXNRHG?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00