What's wrong with this plant?

[ArtichokeAardvark]

I planted a sambucus nigra 'Black Beauty' in April this year. It's grown masses over the summer, but never looked brilliantly healthy and over the past few weeks it's started to look completely dreadful. The lower leaves on all stems are mottled with brownish grey (picture included) and drooping. The newest growth at the very top seems fine, its just the lower leaves.

I'm new to gardening and this is the first elder I've planted. Soil is good - loam, possibly verging into chalky. It is planted under beech trees, but we have a very high water table so the soil never dries out too much even though its technically in a rainshadow. I haven't tried treating it with anything yet as I'm not sure if I'm dealing with virus, fungus, or beastie!

Wise gardening experts of mumsnet, any ideas?

Its very green for a black beauty? We're getting on for autumn, lots of trees are chancing colours and many are dropping leaves. The common elder in my garden, as well as a lemony lace, have both started dropping theirs.

'Black Beauty' here

I don't know quite what you have there but I have the same Sambucus and it looks like these Google images show. It's quite possible that your plant isn't happy under the beeches - I think beeches release chemicals into the soil to deter competition from other plants, so it might not be the rainshadow that's the culprit.

Under trees is a tricky place to grow plants anyway, I have cyclamen corms in my dry shade bed as they thrive in that aspect. I certainly wouldn't expect a shrub/small tree (mine is reaching first floor windows, I pruned it back last winter so this is the regrowth) to grow well under other trees. The competition for resources is just too fierce realistically.

My tree is also starting to lose its leaves, the leaves remain purple but just drop. Your plant looks like it's being attacked by aphids or similar, but I really don't think it's Black Beauty, sorry.

Would agree its not a Black Beauty (too green). You do get Nigra that are green, just not the Black Beauty or Black Lace. Also think needs to be in open spot, not under trees, those that I see growing well are usually planted in full sun.

Any sign of beasties?

Interesting. I've just checked the label and it's definitely meant to be a black beauty! The foliage was also a lot darker when I bought it, it's got greener as it's grown. It is planted under trees but a good 7-8 metres away from the beech trunks (they are hugely tall ones so the canopy extends a long way) and gets lots of sunshine as its southwest facing so I don't think lack of sun is the issue.

I might cut it right back in late winter and see what happens. If it grows back green I'll know I have an imposter! Ditto if it's still not happy I'll move it elsewhere.

The leaves are a very different shape as well as colour.

I wonder if Black Beauty is grafted? It’s normal practice for named varieties of trees a) because you need the tree to be genetically identical to its parent, which is guaranteed with a graft b) it’s the quickest way to propagate in bulk. If so, what can happen is that the graft fails, and the rootstock takes over, which in this case would be common elder.