Posted: 07/05/2017 at 08:32
That's gardening for you Rob
All those plants will recover and be fine. It just looks a bit manky. You'll sacrifice flowers on most of them this year.
I'd leave the damaged 'ends' for now, and once the weather is set fair with no more frost, you can trim and tidy them then. Damaged leaves on hyrangea will drop off, but when you have some new helathy growth on them you could remove the blackened leaves. The dahlias would have needed more protection than a plastic bottle if they were in the ground, but I'd reckon you could take the frosted bits off those, and they'll be fine. They'll just flower later than usual. The magnolia will also be fine, but you'll have to wait till next year for your display.