Question
Hello! I'm in Eastern Washington (climate 6a) and despite Western Wa being lush, rainy, and green, the east side of the state is essentially desert-y. I just bought some small, gorgeous H. macrophylla- small, in one gallon buckets, with 1-2 large mopheads in bloom. I have put them in planters because I'm nervous about the winter. My questions are regarding care of these pretty things in to the winter: I put them in planters so I can drag them in to the garage this winter.I'm planning on transplanting them as they get larger, and (granted I keep them alive, transplanting them to the ground later in their life.) They bloom until "hard frost", when should I pull them in to the garage? How often do I water them while they're dormant? When in the spring do I place them back outside? I've read about taking them out of their dormant phase too early then letting them get hit by frost kills any blooms you have forming. The blue flowers need acidic soil.. could I use coffee grounds to acidify the soil and then a general plant fertilizer? I have a really shady back yard, that I'd say only gets a hour or two of direct sunlight a day, is that enough in a hot dry desert climate, then getting shade the rest of the day? I know they love water as well, and I've been keeping them moist daily. I've also read that in my climate I can plant the hydrangea, put a cage around them, fill the cage with leaves and pine needles then tarp the cages. That makes me too nervous, especially if we get a cold snap.. is it safe and reliable to do in my climate? I just don't want to trust bad informaiton and end up killing my plants!
Thanks in advance for your help, I just need to learn what to do to keep these gorgeous plants from demise in my desert-ish home.
Sarah

Answer
Hi Sarah,
Thanx for your question.  Zone 6a isn't a bad zone for the type of hydrangeas you have.  I'm pretty much in that zone in Eastern Kansas.  We have cold, relatively dry winters with an occasional ice storm and maybe one or two deep snows.  The springs and falls are mild although we can go into  a hot phase in late spring and early fall or an early cold snap in April or October.  The weather is pretty unpredictable.  I wouldn't mess with containers for your hydrangeas.  They need to be planted in a place that gets full sun except maybe for some shelter for full afternoon sun if you get into the mid90s to 100s.  I see them growing in the Kansas City area in places where they don't get sun for the whole day.  They seem to do well like this and in our type of climate they don't like too much shade.  They do need to be kept moist so a good cypress bark mulch will do well.  You can use coffee grounds to fertilize but there are also some good organic fertilizers for acid-loving plants out there.  I do not mind recommending Miracid for this.  We don't seem to have a lot of trouble in Zone 6a getting nice blooms even though we occasionally get a late cold snap.  It might do our peaches in but it usually doesn't decimate the hydrangeas.  I do believe the mulch of leaves in the wire bin is very helpful and very realistic.  The hydrangeas are not as delicate as one might think.  The problems they have are more in Zone 5.  Here's a link I think you'll find helpful and please feel free to contact me anytime about your plant questions.
I hope this helps.
Tom

http://www.hydrangeashydrangeas.com/index.html