Touch or look at potting medium to make sure it is still moist, the main problem I have had with plants (of various kinds) in the garage during cold periods is them drying completely out without my seeing it.

Of course for this to work your climate area will have to be one where it does not freeze hard inside the garage - plants in containers are significantly more vulnerable to cold than the same kinds would be planted outside in mulched beds. Organized experimentation has shown a tendency for woody plants to be about 20 degrees F. hardier in the ground than above it.

Also if any of yours are examples of Hydrangea macrophylla cultivars that were grown and presented as florist pot crops some of these can be less hardy than kinds offered for garden use in cold winter climates.

It's not moist to the touch. I thought it's best to let it completely dry before watering?

Soil should stay just barely moist to the touch - not dry out completely. And you really do not need to water in the same manner as you would when the plants were outdoors and still in active growth. Just topping the top of the pot once a week or so with ice cubes should be enough to keep the soil moisture at an even level.

Should the leaves fall off once it gets colder in the garage? What can I expect? Is it the same for the mums and roses?

None of them will want to dry out completely at any time. With the hydrangeas being the least tolerant and the mums the most. You should make sure your hydrangeas aren't shriveling up and dying.

I looked around in my warmer locale's leaves... my only potted hydrangea, a mophead, is in the garage and has leaves that look as if they are curling -a little- but they have, very slowly, been yellowing and falling due to the time of the year... colder temps, less sunlight in the garage, dryness of the garage... It is getting water every week-ish or so; I test the soil regularly with a finger inserted into the soil to a depth of a few inches. Insufficient water would have shown signs of leaf browning at the edges and moving inwards.

My non-potted mums and roses, planted outside still have green leaves, blooms, etc and do not look curled. All the hydrangea varieties planted on the ground outside do not show leaf curling; they are mostly green, except for a few oakleaf hydrangea leaves that are turning a few little colors at last. Paniculatas started loosing leaves faster than the other hydrangeas but their remaining leaves still look all green. Got some green leaves and month-old blooms on some serratas. Arborescens are mostly green with a few yellowed out leaves. Smoke bush and Crape Myrtles have changed colors and lost leaves. Oh, yes, then there are those Quince bushes that have some weirdo recent blooms.... sigh... they just want to be different, don't they? ;o) Ha.

My weather has n-o-t included frosts yet; just low temps above freezing (35F is the coldest so far); watch out for those frosts as they could damage/zap leaves even in the garage if the soil is dry. Of course, no biggie if they do as the leaves will eventually "go" this season. I do try to keep an eye for those "chance of frost warnings" though. Here is knocking on wood for me and everyone else!!! Knock, knock, knock!

I tend to deeply water the root zone of ground/potted plants when early frosts are announced (the night before)... if my brain remembers to do it. I also keep the outside plants well mulched.

Ok, after a few days my hydrangeas leaves are still curling and falling. I watered them. But I also see new growth including new buds and leaves. The weather is up and down here. The other day it was 67 degrees during the day. Now it's back to the upper 30's. The garage has stayed around 40ish. I really don't want to lose them.

My roses and mums leaves are turning yellow. The rose buds are aging and falling which I assume is normal but not the yellowing.

I took a look at my outside hydrangeas. They are all curled up for the winter. The outside rose are green.

This is my first year overwintering in the garage so I'm not sure what is normal. Any advice would be great!

It sounds fine, Kay. As long as you are keeping the soil moist, they should be fine in the garage. They are deciduous so they will loose all their leaves "asap" and look like dried out sticks when leaves fall. Temps below freezing will help aid this process.

I actually have kept my potted one outside so the cold temps will make it go dormant but so far, temps just have not gotten below freezing and so, its leaves remains green. Sigh... Hee hee hee.

Make notes in a wall calendar or in an electronic calendar so you know when it finally goes dormant. To compare, in my neck of the woods, dormancy has occurred as early as mid November and as late as mid-to-late December. Places south of my location (Dallas / Fort Worth, Texas) will have hydrangeas go dormant later than my dates. Places north of my location will have hydrangeas go dormant earlier. Oakleaf hydrangeas here have even kept their leaves "on" all year in some very mild winters before (not likely in Z6 though).

Just make sure they get water once a week or once every two weeks (you can insert a finger into the potting soil to see if it feels dry or not).

OK I'm in zone 6 Ann Arbor, MI. Thanks!

Set up a reminder in an electronic calendar so you do not forget to check the soil for dryness. Or use a wall calendar (put a check mark on the same day every week to indicate you have checked the soil).

It has been so cool, like 5-(-10) every night for the past week and a half. The soil is frozen. What should I do? Will they die?

Kay, most Hydrangeas are pretty hardy, what gets zapped might be the buds and next years flowers. You will have to experiment and see if they bud out in the spring and if the buds produce flowers. If they do lose the flowers, you might look to plant some that are more apt to bloom in your zone. Go on line and check some of the catalogs and see which ones are hardy in your zone. Google 'free hydrangea on line catalogs.' In the spring, walk around your neighborhood and see what is blooming. Ask questions at the nurseries in your location. Bringing your plants into the garage is a good start. Hydrangeas are sensitive to their location - sun, shade, available water and such. The good news is that there are hundreds of cultivars and you will find many for your garden - you have to do the research and this forum is a great place to start.

There have been light green shoots growing out of the plant, for about 2 months, even the soil. Is that a good sign?

Congratulations! Start to put them out in a protected shady spot as soon as you are sure there will be no frost. They will green up with some indirect sun. If they get full sun, the new leaves will shrivel up. They are very tender but will harden up with gradual light and longer days. Keep them moist - not wet - check that they have good and fast drainage. If you are really excited to see the roots, carefully dig one up and check. Return it to the pot being sure to make a space for the roots and replace the dirt carefully in the hole. Don't pull up the new plant or push it back into the hole. A few minutes of tender care will be paid back by successful cuttings all surviving. When the roots are nice and thick, carefully pull apart each plant and place each one in its own pot. You can use a 4inch pot at this stage, but we prefer square quart pots so they do not have to be potted up (transferred to larger pots) before going into the ground. If you have the room, the new babies can stay in the quarts for one to two years.

Am I reading this right. New shoots coming from the crown of a potted plant. Hmmm, gives me some confidence on possibly keeping 1 in a pot to establish grown (with the intention to plant), but the potted plant will have a better rootball than if I had planted, then transplanted twice.

Sorry, Kay Ann, I got you mixed up with another person who was rooting cuttings. Sounds like your potted plant is doing just fine! Are you planning on putting it in the ground? If so, give it till you are sure there will be no frost - a little probably would not hurt - and then plant is a protected spot. When you do plant it I would suggest - and this will get some other opinions - washing off the soil around the root ball and planting it in a hole using native soil - same as the hole for the plant. Don't worry about the tiny white roots - they will quickly be replaced and NOT harm the plant at all. Here is a link to download an article that will describe how and why to replace ALL of the soil from the root ball. https://s3.wp.wsu.edu/uploads/sites/403/2015/03/fragile-roots.pdf  Check your download file for the article. If it does not work, copy and paste link into your browser.

I was planning to keep them in pots since I'll be moving to Zone 8a next year. They have the brown blooms on them. When should I cut those off?

Hi Kay - I would pull the plant out of the pot and look at the roots. Maybe repot 1 size up depending on what you see. For sure you can cut the brown blooms off. How warm is it now. You can always just wait till it warms up a bit more and just make your cut right above the where the bud is.

It's only in the upper 40's here. I will probably have to wait until early May to take them out.