It's hard to say :-( Cold damage to flower buds on macrophylla are most often associated with late season freezes, occurring after the plants begin to emerge from dormancy. But it can also happen early in the season if the plants are subjected to cold temperatures prior to entering full dormancy.

While it might have appeared frozen under the house, I am sure it was a far more protected area than if the plants were left exposed in the garden, so perhaps all is not lost. OTOH, moving them under the house implies these were containerized plants to begin with. Containerized plants are far more vulnerable to cold damage - not to the buds but to the roots. Plant roots, which are normally insulated by the garden soil, are more vulnerable to cold damage by as much as 20 degrees than is the top growth. Again, the protection offered by being out of the weather and under the house (some radiant heat is being produced) may be sufficient to avoid any significant cold damage.

FWIW, low temperatures here (just a bit north of you, along Puget Sound) have been in the teens all week. None of my hydrangeas has been offered any protection and I don't expect to see any significant loss of flowering next season. We went through a similar, extremely cold spell early last winter also, and it had no effect on the blooms.

btw, if you hit a low in the single digits, you are more likely in zone 7 rather than zone 8.

Kelso/Longview is on the news this morning at 7 .I am at about the 1200 foot level overlooking them. My temp. gage is reading -5. Yes they are in containers with a few of the newer ones having been bought bareroot in sep. Do you think it would help prevent further damage if I covered them as well? I was thinking of letting them thaw out next week then covering them for the rest of the winter. The pipes froze so I know it froze under there.

Hi Madeyna - I'm not an expert but from what I understand, those *fat buds (leaf or flower)* on the nodes of the canes, are provided by nature w/ several layers of protective coats(bracts) & should be able to survive freezing for a short while. I would, however protect, if temps fluctuate ... also freezing winds are more devastating due to drying effect.

For your potted collection & in your zone, unless you have a protective system that works, huge cardboard boxes from the big-box/appliance shops might help ... cut out small holes to breathe & use bricks to hold down ... much like using rose cones.

Good Luck & Happy Holidays!

Thanks I hadn,t thought about big boxs .They would make a perfect cover the the ones under the house. We have a ice storm warning so I.m hoping the outside Endless summer ,Snowflake and Pinky winkie will be okay with their landscape fabric covers.