Question
I live in Southern California about 10 miles from the coast.  We have mild winters and warm summers.  I have two wisteria plants that I purchased from a nursery two years ago in January that were flowering nicely at the time of purchase, but did not flower the following year.  This year, we've not only had a dry winter, but we've had several mini heat waves through out December and January.  One week the high would be around 60 (don't laugh, that's really cold for us!) and the next week it would reach the upper 80's with dry inland winds and gusts.  Then, the marine layer would roll in, cool things off, and we'd get a few days of rain from Alaska and the temperature would drop.  I did fertilize my wisteria in December, as my Southern California gardening book instructed, but they shouldn't be leafing out for another month or two!  With these hot spells followed by very cold wind and rain, both wisteria are leafing out and producing what I think are flower buds - they're very large and round and the most mature of them is purplish.  Finally, I seem to have flowers, but we're expecting another cold rain this coming week.  I'm concerned that the buds will die... I certainly doesn't get cold enough for them to freeze, but I don't know how the chill will effect them.  The vines are not very big, slowly climbing a six-foot trellis that could be covered, but I don't want to break any stems off.  A Japanese maple growing in a large pot nearby has also put out a few tentative leaves and even a few small flowers (I didn't know it would flower...it's never done that before) but seems to have thought better of it.  Half the plants in my garden have started to leaf out and then stopped, and our tortoise came out of hibernation in the beginning of January and then went back into his hole a few days later.  Is the constant back-and-forth weather going to adversely effect these two wisteria, or will they just ride it out?  Last year one of them did put out a single flower - not a cluster, just one flower - during an 80 degree hot spell that quickly shriveled when the temp dropped back down and did not flower again the rest of the year.
Any advise would be very much appreciated, whether I should cover them, give them extra food, or just let them be.  I've searched the net, but all I could find was information about pruning them.
Thank you!
-Maegan

Answer
Hi Meagan,
Thanx for your question.  Sorry to be late getting back to you.  I had to go out of town unexpectedly for a few days.  I know it seems kind of risky with the ups and downs of the weather in your area.  Your wisteria should not suffer because there will be no frost.  I would not fertilize any more until later in the season.  Make sure the fertilizer is not heavy on the nitrogen side or all you're going to get is rampant green growth.  Look for fertilizers for flowering shrubs higher in potassium and phosphorus.  Once Spring is in full swing in your area fertilize according to the directions on the package.  If you anticipate cool night temperatures, you may cover the flowering sections with a sheet which will protect them from cold winds.  Remove the sheet in the morning so it won't unnecessarily heat the plant up.  Your plants should be fine and as they mature, they will put out even more blossoms.  Be sure to control their growth because if they go rampant, the blooming will slow down and eventually disappear.  By the way, Japanese maples and other maples do bloom but the blooms can be pretty obscure.  I hope this helps.
Tom