Bunny: Mildew normally occurs because a plant is very dry at the roots.

Pippa: Yes, it’s definitely mildew. If you look underneath the leaves they’ve got a dense coating of white fungus. A south-westerly wall couldn’t be a worse situation for them. The foundations of your house are pulling a lot of moisture out of the soil, and if there’s an overhang of tiles or guttering, it’s stopping rain getting to the roots of the plant, so it’s a pretty dry site. Honeysuckles are woodland plants, so you’re going to be fighting a constant battle. By all means try plenty of water, and a really good mulch around the base. Thin the growth out a bit to get better air circulation. Continue spraying every two weeks if you must, and you may get on top of it, but it’s going to be a hard battle. I would say much better to scrap them, plant something that’s going to be happy in that position, and then plant honeysuckles in a partially shaded spot where they can have a decent, moist root run.

Bunny: I would be tempted to carry on a bit longer with these, to try to get them established. I have grown honeysuckles successfully on a southerly wall, but these are going to be particularly thirsty because they’re young and haven’t got very deep roots yet. Keep watering them, even when it’s raining!

Bob: Bunny is confident they’ll grow out of the problem, but I don’t think so, so I’d say get rid of them!