Under 32F weather is usually ok up to a point and will not hurt the buds if it is "close" to 30 and the 20s but, when it happens early in the Fall or late in the Spring, it is hard to guess. So the best you can do is to "winterize" them anyways as soon as possible. There is no script that one can check regarding when the temps have damaged the buds.

If the plant began to harden for this type of weather, the flower buds may be ok. If the plant was unprepared, the buds may have been damaged. They are now invisible so you will not know for sure until Spring.

Last winter, wild temperature swings were the problem in my neck of the woods. One lacecap did fine but the other one had no blooms.

I have not tried pine boughs to protect hydrangeas but you could cover NB with hay, pine needles, hardwood mulch and other types of organic mulches... Snow is a good insulator too.

I am aware of Wilt Pruf but have not used it.

Luis

Thanks Luis, that's about what I thought and I did go ahead and winterize them yesterday. The leaves were still green and perky prior to the extreme cold, so I don't imagine the plants were quite prepared.

I've read that wilt pruf and pine boughs are used on roses, so I thought perhaps they'd be helpful for hydrangea. NB is such a tiny plant right now I'll just be glad if it survives the winter. I do have hay I could use.

Thanks for your insights and taking the time to reply : )

You're welcome. Anything you can use to protect newly planted seedlings and cuttings in their first year outside will work with your NB. The more you pile on to protect the end of the stems (where the flower buds are), the better your chances of getting bloomage in the Spring. Even if the end result looks weird. Check it mid-winter and add more mulch (in case settling exposes the stems or the winds get rid of some of the mulch).

We had some cold weather in the mid 20s that basically killed the green leaves. They looked quite bad, as usually happens. The temps then went above freezing for a weel+ and a thunderstorm that passed over the area yesterday made most of the macrophylla leaves fall so I am picking them and throwing them in the trash in the case of hydrangeas that have some leaf spot.

I hope you enjoy Nikko Blue. NBs tend to be quite sturdy and large so this may be the last year you can call it a tiny plant. If your soil is acidic, you should get nice blue blooms!!! Enjoy and have a Happy Thanksgiving!

Try out this site:
http://www.hydrangeasinthenorth.com/
The author has developed a method that works for his hydrangeas in upstate NY. He actually recommends pine boughs for winter protection. I'm going to try it. Best of luck to you.

The hydrangea plant still has it's leaves on it, although they are drooping. Should I pick the leaves off the plant?? The plant is about 30 inches high. I don't know what type of hydrangea it is. Is there any thing else I should do to protect the plant for winter??? Thanks for your help.

They will for on their own eventually; so will the blooms although "eventually longer". But if your plants suffers from some type of fungus on the leaves (leaf spot, etc), it may be best to remove the leaves when they dry out and throw them in the trash. Winterizing in your Z5 is usually needed only for hydrangea macrophyllas (aka, mopheads or lacecaps) and for serratas (a smaller version of macrophyllas whose leaves are serrated). For other varieties, maintain 3-4" of any type of organic mulch up to the drip line.