I was wondering if I at least put trash bags over my hydrangeas, will that protect them from this freeze?

The plastic will not protect them from freezing. There is virtually no insulation. The plants will surely freeze where they come into contact with the plastic.

You could put light blankets or sheets over them. Definitely not plastic.

If they are small enough, you could put buckets or tubs or something over them.

I've actually tried protecting tomato plants with plastic buckets..... Didn't work...
Ditto on using sheets and blankets.... Even quilts and sleeping bags!

Plastic sheeting and trash bags develop frost on both sides.... Worse than using nothing.

You know what the citrus growers do in Florida?
They run sprinklers....
I'm not about to run sprinklers all through the night, but I have rinsed off a light frost in the morning before the dawn.... Sometimes it works....

Marie, it somewhat depends on how cold your weather is supposed to be. Just at or below freezing? Down in the single digits (which is what we're getting at the moment)?

If only a little below freezing, covering with a blanket or something will certainly help protect them, although I agree that plastic isn't the best idea. You could also try placing a bucket, jug or whatever of hot water underneath the covering with the plant. And, maybe for future reference, if you could make some sort of cage or other type of support for a covering that wouldn't be touching the plant, that would be ideal.

On the other hand, if your temp is going way down, I'd still suggest covering the plants up as best possible, but they will likely suffer some damage.

There is a dilemma. You can put enough cover on plants to protect them for a night down to about 25F, but if it snows the weight on the covers can break the plants. It depends on how high and sturdy the plants are.

I had to many to cover and as you know yardenman, we have had some crazy weather this week.

makap said:I had to many to cover and as you know yardenman, we have had some crazy weather this week.

I used some covered hoop supports last week. I didn't have enough, and it got too cold for them anyway. Even covered, my early daffodils just fell over.

Sometimes nothing is enough. I lost all my saucer magnolia buds this year, and half my daffodils just fell over. The daffs still flowered, just on the ground. It was a bit strange...

My Daffodils did the same
I am ready to just dig up my hydrangeas and replace with an evergreen in the front of my house. They are old and have not bloomed in years due to this strange weather we have been having.

Last year about this time year, give to take a week, we had a cold snap that totally screwed with the lilacs up here and zapped some tulips.
It looks like we will not have one this year but I will not hold my breath.
Back in 1965 the temps. this time of year were -20s F followed by sixties and seventies not long after.