Winter care for perennial container garden

[mshel]

Hi! I hope a more experienced container gardener can help me keep my garden healthy through a Northern VA winter. In May I planted a wonderful container garden on my rooftop terrace. I have evergreen shrubs, tall grasses, weigela, salvia, dwarf grasses and a few annuals.

I don't know how to care for the plants during winter. I love the tall grass! It's almost 5 feet high and is beautiful. The weigela is training nicely along a trellice. The evergreens are also doing well. I have a built in watering system, so it's very low maintenance.

Does anyone have suggestions for what to do with the plants during winter? Do I cover them? Prune them back? Bringing them inside is not an option...I don't have much room!

Any suggestions are very much appreciated!

[Grey]

Your garden sounds lovely.

Your evergreens should be just fine.

What kind of grasses? Some grasses will survive a winter, some will die back and return in the Spring, and some will die in a cold winter. It all depends upon what they are. I have an aztec grass that I must cover or they will die back to the ground, and it took all summer for them to begin to fill out.

Salvia will die.

I'm not sure of the wigela, so hopefully someone else can help you there.

[Brie]

It would be better if you could take them inside, but if that's not an option you could trim them back then cover them with a tarp or blanket to save the roots. You'll just have to let it grow back next year.

[opabinia51]

For plants that you cannot move inside (preferably into a well lit garage as apposed to inside because plants need their dormant period) youk can build structures that you lay over the plants with plastic and wood to cover them for the winter. I had some neighbours once that did this.

[mshel]

Thank you to everyone who replied to my questions about winter care for my container garden.

The grass that I am the most fond of (and worried about) is a lovely Maiden Grass. It is currently about 4.5 feet high and about 4 feet wide. It has been healthy and beautiful all summer. Does anyone have an idea about what I should do with it during winter?

(again, I'm in the high real estate market of Northern VA, where there is barely room for me, let alone my plants, in the house, so coming inside is not an option!)

The other that I am not sure about it the Weigela bush. It has trained nicely along a trellis, but I'm not sure if I can leave it as it is, or if I need to prune it back and let it grow again next year.

If anyone has any experience with these plants, I'd love to hear about it. I am considering building the "shleter" that was suggested before. But someone asked me specifically about what type of grass plant I had so I wanted to answer! Thanks very much.

[Newt]

Hi Mshel,

I'm 'around the corner' from you in Maryland, so I know your conditions. Your greatest concern will be drying winds to your evergreens and the freeze and thaw that can happen in our crazy winter weather that we get here. I would suggest you use an anti-transpirant on your evergreens and water everything well before a hard freeze. Check the label to make sure each of your evergreens will tolerate it as some don't.

It's best not to prune at this time of the year, especially if your plants aren't dormant yet. The warm weather can cause a growth spurt and the tender growth won't have time to harden before a possible hard frost. Best to prune in the late winter or early spring - late February to March.

[url=https://www.ces.ncsu.edu/depts/hort/consumer/factsheets/ornamental_grass/miscanthus_sin-gracillimus.html]Maiden grass is Miscanthus sinensis 'Gracillimus' and hardy in our zone[/url], so it will be fine. Cut it back before new growth in spring. You can enjoy the movement all winter.

There are many salvias. Some are hardy here and some aren't, so it will depend on which one you have. I wouldn't cut it back as the birds might enjoy the seeds this winter.

You will want to make sure that the pots or planters don't freeze and thaw and refreeze during the winter. You may need to find a way to insulate them.
https://www.google.com/search?hl=en&lr=&q=insulate+rooftop+planter&btnG=Search

Your weigela is hardy here so not to worry. Any branch tips that get freeze dieback can be pruned in spring. Since they bloom in spring they should be pruned within two weeks of finish of bloom for best flowering.
https://www.springmeadownursery.com/article_4.htm

Newt