Question: Two years ago I bought a beautiful Sambucus Black Lace, which last year produced lovely pink flowers. It is now about three foot high and is planted in one corner of my lawn.
The problem is that some of the stems are covered with some kind of black fly, only these are more of a dull grey colour, and they are obviously weakening the plant, because a lot of the foliage has died and is littering the grass beneath.
Can I save the plant or should I just dig it up and buy another?
Answer: There are several species of aphids, of varying colours - those on your elder, as you say, are blackfly. They suck sap from the plant, causing foliage to distort, and the plant may be weakened.
The blackfly are active on the elder only in the earlier part of the season, so this is a temporary problem and new growth should appear.
Try to look out for blackfly in April, before the foliage curls, and wash them off. As a last resort, you could use organic insecticides based on plant oils or fatty acids, such as Bayer Organic Bug Free or Vitax Organic Pest and Disease cotrol.
I would give your elder another chance - it sounds too lovely to lose.
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