By Valatwell
Essex,
United Kingdom 
This year, many plants that would have died back on their own are still in full leaf and even have flowers still, penstemon, gaura, large alstromeria. Should I cut these right down now, as I don't fancy waiting till the weather is really bad to do it as my health isn't at all good. I really don't know what to do for the best. I'd be grateful for any advice received, thank you
18 Nov, 2021
Answers
I agree with the advice. I leave my penstemons alone until mid spring too.
I'd also leave the Gaura untouched as the remaining stems protect the crown. If you decide to cut back now protect the crown with a mulch.
The Alstromeria die back when they are ready and they do have a storage tuber that needs to be fed by the foliage.
If you hate the sight of the dead stems then cut them down now but if we have a hard winter you may loose them. If we have a hard winter you may loose them anyway :o)
19 Nov, 2021
THANK YOU BOTH FOR YOUR ADVICE, i SHALL LEAVE THEM TO LOOK AFTER THEMSELVES AND KEEP MY FINGERS CROSSED THEY SURVIVE. THANKS AGAIN
19 Nov, 2021
I agree, just leave them. The sky won't fall. They'll be fine and you can tidy things up later. The leaves will mulch down naturally and protect the crown from freezing as do the hostas.
19 Nov, 2021
Leave Penstemon alone, the top growth protects the crown over winter. Cut them down in Spring.
Don't grow Gaura so cannot help with that.
Alstromeria are not cut down as such. They are prepared for dormancy by having the dead stems pulled out.
18 Nov, 2021