Surfinias and trailing double petunias

I have one surfinia and three trailing double petunias in my hanging basket. They are dying off slowly as the season changes. I'm deadheading daily and feeding every 3 days now which gives them a boost each time, but it's clear the end will be in sight soon as the basket gets more faded and sparse.

A very newbie question, but a quick Google search indicates these are both perennials - is that right?

How should I store the plants over autumn and winter to keep them safe and have them come back next year? - My greenhouse is nearly up now if that helps, though at present I have no plans to heat it.

If there is no way to save the plants themselves for next year, is it possible to take cuttings or have I left that too late? If I can take cuttings, can I follow a typical YouTube instruction video or is there anything special I'd need to know about these plants? (Like for example I saw on Beechgrove that you shouldn't use rooting powder with pelargoniums... there might be similar tips for these plants.)

Thanks

 

Hi Anzia,

I 've never kept them from year to year as I find they're cheap enough to grow from seed or buy again every year.
However If you have any that you particularly like, they're easy enough from cuttings. Just take a piece about 3" long and remove the bottom set of leaves. Insert them around the edge of a pot.

I personally have never used rooting powder in my life, it's just a personal preference.

 

Thanks @Anthony Rogers for the advice