I seem to have numerous problems getting my Sambucus Racemosa Sutherland to survive (never mind thrive!) in my garden! I've tried it 3 times and they've all disappeared despite the claims that it's a hardy plant? It's planted out in an open, sunny site next to a Purple Smoke bush and a blue butterfly hibiscus.

I know I have heavy clay soil but I've used soil conditioner and grit and manure to improve drainage.

Now, I've resorted to getting one in a pot and have left it just there. However, just today I've noticed loads of black creepy crawlies up and around the stems and the plant seems to be looking rather sorry for itself! Does anyone have any good advice to encourage a healthy Sambucus??