Can anyone tell me what is going on with the leaves on these plants? (pics attached)

[curlyLJ]

I've recently spent a lot of time and effort trying to get my garden in order and it's starting to look good, except for the leaves on these 2 plants. They are in totally separate areas of the garden and their leaves are looking like they have some sort of disease/problem. My friend however said it may be because I watered them when it was too hot and sunny and have scorched them.

One is a delphinium and is a new plant I bought a couple of months ago, the other is a Sedum (stonecrop) and it has been in the garden for years (I have others and they are fine). Thanks in advance if anyone can offer any diagnosis/solution.

I can't see very well but I think it's just mildew. Some plants are prone to it more than others, it's a sign they have been stressed, probably lack of water.

It won't kill them , just doesn't look very nice. You can spray them with a fungicide if you like. It won't fix the old leaves but the new ones will be ok .

Spray them with water with some milk added - a tip from a gardening friend who really knows his stuff.

The first one looks like powdery mildew, caused by stress, like lack of water or poor growing conditions.
Not really clear on the second.
I have also heard of the milk treatment. 30:70 milk and water sprayed on to the leaves about once a week. It's more of a preventative measure apparently, so it won't cure damaged leaves.

Will the milk method work for Dahlias with a mildew issue.

?

Well I haven't tried it on dahlias, but it works on courgettes, if that's any help! If you are concerned your courgettes are not producing enough, and are not sick of the sight of the bloody things

oooh yes my courgettes (and pumpkins) always get mildew. We normally have thousands (slight exageration) of courgettes but this year has been pretty bad :(

I might test the milk thing on one Dahlia and see how it goes

Thanks for the replies.

If it's just mildew, what do I do at the end of the flowering season - should I cut it right back so it grows better next year? or just leave it alone to do it's thing?

As for the milk tip, thanks I will try that although I have never heard of it.

I agree about the mildew on the first plant. The second does look a bit more like scorch from having water droplets on the leaves. I normally leave mildew to sort itself out - I put the worst affected leaves in the green waste bin and then water the plant well, as it's largely a disease of drought.