our temperatures are normally in the teens and twenties all winter long and my annabelle does perfectly fine. was it healthy before you got the cold snap? sometimes it just takes them a bit of time to wake back up

38F isn't cold and didn't damage your Annabelle in your mild temperate garden. It may just be slower to bud out so early to worry about it. You might give it a little more time, then try the fingernail test....make a little scrape in the bark and look for green tissue underneath. If you don't find any, you may have a problem but it wasn't caused by cold.

Isn't annabelle cold hardy to -30F?

I was kind of not dormant yet, and then the cold happened and kind of went "like it had died", but so did all the other hydrangeas, and they woke up a long time ago. It looks like a pile of dead sticks with no signs of green. By now I should have seen some signs of green, but I am just going to have to wait it out, I guess. I just wanted to know if the ones in the south ever die when they get cold? I know it's supposed to be cold hardy so I am just puzzled. Maybe it died of old age? It was over 10 years old. Maybe it should have been dormant before the cold hit so if was dormant at the time of the cold it would have lived. Maybe living in san francisco has made it spoiled and not cold hardy?

Sorry, you can't "change" the hardiness of a plant :-) That is something that is genetically programmed and even growing a very hardy plant (the Annabelle) in a very mild climate (zone 10) will not reduce or alter that hardiness. All of my macs are beginning to leaf out now but no sign of life yet from the paniculata, which was new last year. It, like the arborescens, are just slower to emerge from dormancy than the macs. Even my very tiny 'Fuji Waterfall', still in its #1 container all through our 7-10 day cold spell of temps in the teens, is beginning to show signs of life.

OTOH, my 'Little Honey' oakleaf, also planted in a container (but a large one) is still fully evergreen...or evergold :-) It didn't even develop much fall color this year if at all. Every single leaf is still intact and quite succulent and lush. What's up with that?? Usually by this time of year, the leaves, which will have their fall color, will have begun to dry and shrivel and soon fall off with new growth.

Just be patient.......it'll return.

Thanks garden gal. There are some large hydrangeas here in San Francisco, but not mine, that never lose their leaves in the winter. These old huge ones in front of houses, stay leafy all year, but the blooms become old and they stop blooming, but never go dormant at all. It may be my exposure is western and some of the others could be southern or eastern or maybe the large size and being near a house causes super winter protection. They look passably nice all year, but better in the warmer months.

It's hard to believe that Annabelle, being the H. arborescens could survive for long in z10 without being induced in a dormancy. This plant NEED dormancy!