Aster Pruning for winter?

I bought some hardy asters two years ago. Last autumn they were still small so I did nothing but cover them before the winter. I covered them too early and a warm sunny day fried them. But they forgave me and came back this year.

I know not to be hasty to cover them again but I keep hearing about cutting them back in the fall and have no idea how to do this. My other perennials such as phlox, peony, die down and I clean them up in the spring before the new growth gets more than an inch high but these asters, I'm stumped.

Here is ampicture of them right now. Too early to cut back but the right time to find out what to do when the time comes.

 

Think I would leave them alone at least until the first frost.
I dont think you need to cut them back, just a quick tidy up next spring would probably do.

 

Thanks @pete. That is what I will do. These plants are expensive and it is heartbreaking to lose one.

Spring it is!

 

Lori, that is just my guess, I think it will survive under your snow all winter, they are pretty hardy normally.

 

I have a cold frame cover for that side. It's certainly not air tight but it should protect them some. When there is a mild, sunny winter day, I shovel a bit of snow under the covers to moisten the area. Hope that works for these fellows too

 

I find that interesting, do you consider that kind of cover necessary, as I was under the impression that this kind of Aster, what I would call Michaelmas daisy are totally hardy.

I probably underestimate the amount of cold you get, but remember seeing wild versions of these growing in places like Colorado, which get some cold winters, worse than we we get here.

 

Yes, it would be pampering. I had made the cover before I switched over to the asters so I am debating with myself whether to go ahead and put it on when snow flies. There are some primroses and also allium in that bed now too but they are also hardy, from what I understand.

 

You get that frost that goes right into the ground, not something I have seen here for many yrs.
But I think primrose and allium should be able to live with that under the snow.

 

Yes, it can freeze down to about 18".

I'll find another spot for the cover. Or just leave it hanging on the fence at the side of the house.

 

That is unbelievable, I'm not sure what can actually survive that.

 

Lots of things survive. I think it only freezes down to around the 9 or 10" mark in my area. I have made the mistake of trying to pull out metal plant supports - you know the ones that are thick with corkscrew tops - before the middle of April and bent them because they were still frozen in the ground. And I shove them down about that far.

 

Apple and pear trees, Phlox, Iris, Hosta, Peonies, Clematis, Michelmas Daisies, Roses, Lonicera... all perennials getting the usual at least minus 10 centigrades winters, sometimes worse in Finland. The ground freezing half a meter down, and hey ho, the plants are just fine.

Living in this temperate climate I do also keep getting surprised with the plants my Finnish fellow gardeners grow without a worry.

 

I leave my asters un-pruned until late winter or early spring but I now add about two inches of organic mulch. I do not cut the blooms as it allows the birds to collect the seeds from the flowers and keep the growing cycle going. Water only if the soil feels dry to the touch.

 

Good to know @luis_pr . I also like to leave flower heads for birds to enjoy. It's been raining nearly every other day here so luckily I don't have to do any watering.

 

I agree with Pete but the only thing I would add I would reduce the top by a 1/4 to stop any wind rock loosening the roots as they do get a bit top heavy plus a mulch around the base would help keep them safe over winter.

I have found asters tough plants they tend to be neglected but a good feed in early spring and well watered during the summer they will really put a show on for you and keeping them well watered stops them getting or lessen having mildew.

Spruce