Confession: I stole a massive azalea from a local nursery.

[Glaucus]

Dsd- so I read through the overwintering guidelines and they are very thorough. The only question I have is- if they are so sensitive, why not bring them inside like a tropical? ...assuming adequate space and light of course.

Almost all evergreen azaleas are from temperate regions. Not subtropical. On top of that, your specific cultivar was bred from R.mucronatum forms in Geneva, Ohio by Mr Girard.
So they are not that susceptible. But as evergreen plants with shallow roots, they face some more risk than say pines or maples.

Putting it in a pot makes it more susceptible to the winter cold. People generally say that takes off a single point of hardiness zone.

Bringing them indoors has problems associated with it. They need a dormancy period.

Winter is generally a period of some anxiety for all expensive bonsai. Because while they are dormant, you can't monitor their health. And a tree cannot recover from poor health either.
So some azalea lost over winter are not actually killed by the extreme cold, I would say. I have not seen many images here of dead or damaged satuski bonsai with clear frost damage.
If you had a 500 USD satsuki bonsai, rated at 5F, then you would be in a different situation vs now with nursery material bred by a local nurseryman.

 

[JackHammer]

Almost all evergreen azaleas are from temperate regions. Not subtropical. On top of that, your specific cultivar was bred from R.mucronatum forms in Geneva, Ohio by Mr Girard.
So they are not that susceptible. But as evergreen plants with shallow roots, they

Putting it in a pot makes it more susceptible to the winter cold. People generally say that takes off a single point of hardiness zone.

Bringing them indoors has problems associated with it. They need a dormancy period.

Winter is generally a period of some anxiety for all expensive bonsai. Because while they are dormant, you can't monitor their health. And a tree cannot recover from poor health either.
So some azalea lost over winter are not actually killed by the extreme cold, I would say. I have not seen many images here of dead or damaged satuski bonsai with clear frost damage.
If you had a 500 USD satsuki bonsai, rated at 5F, then you would be in a different situation vs now with nursery material bred by a local nurseryman.

Yeah, I thought they might be subtropical and I could get away without a dormancy. Shucks. It makes sense though.

In my microclimate, we have a up to 120+ inches of snow every year and prevailing winds down to -5 (or lower). It gets a little rough. I do have a drafty greenhouse and a garage. I will use both and hope for the best. I am also thinking to wrap the base in some old blankets. Hmmm. I guess I better figure it out soon.

 

[Glaucus]

They say cold dry winters are the biggest killers. When the roots are frozen for a prolonged time, a plant can slowly desiccate.

With satsuki, the Japanese say that as long as during the way, the snow melts off the soil, the satsuki bonsai is perfectly fine.
Just prolonged periods of cold with freezing during the way, which I believe you have, are harder to deal with, for satsuki bonsai specifically.
If you can protect this tree so it will experience a zone 6 winter, you are probably ok. I assume most of your winters will be zone 6 winters, generally.
So you'd have the option to give it a zone 7 winter for most winters, right?

Things like blankets and bubble wrap mostly help short periods of frost in spring, when the trees have already have waken up, but then there is an unusual cold night. Temperatures drop for just a few hours just before dawn, and could damage the tree. So then, bubble wrap will keep the heat inside.
Because day temperatures are then above 0C, and the drop is short, you can insulate. You cannot really temperature-insulate a plant from being say -5F when temperatures are below that for more than 24 hour periods.

 

[Deep Sea Diver]

Yeah, I thought they might be subtropical and I could get away without a dormancy. Shucks. It makes sense though.

In my microclimate, we have a up to 120+ inches of snow every year and prevailing winds down to -5 (or lower). It gets a little rough. I do have a drafty greenhouse and a garage. I will use both and hope for the best. I am also thinking to wrap the base in some old blankets. Hmmm. I guess I better figure it out soon.

Sooner is better than later getting a wintering over plan done

Heat size greenhouse do you use. Does it have electric nearby?

Our greenhouses are 8x6. We use a standard cheap electric heater plugged into a Thermo Cube Model TC-3: Thermostatically Controlled Outlet - On at 35-Degrees/Off at 45-Degrees which is plugged into the nearby outlet (it’s a gfic - it’s easy to get a plug in gfic). Used this method the last two years. No issues keeping the temperatures in the zone.

Azaleas aren’t the only plants we winter over. We’ve had many species from Chojubai to Mountain Hemlock to winter plant purchases hunkering down inside. .

cheers
DSD sends

 

[queenofsheba52]

DSD, that is good advice. I believe I might be in a similar microclimate to jackHammer: south west Michigan about 50 miles in from Lake Michigan. Our particular neighborhood has terrible winds in winter such that I can't grow lavender or hydrangeas, which should be hardy in my zone. I put all my azaleas inside my unheated garage during the winter. I usually give them a small drink every time the weather gets above freezing, but I realize that is not a long term solution. I am going to look into your set-up with the Thermo Cube.

JackHammer, I kept my first azalea bonsai in the plant room in the basement overwinter and it did die, from not being able to go into dormancy. That was before I had discovered this great site. Live and learn.

Daughter and I will be traveling to NE Ohio next April to see the total solar eclipse. I'd love to visit this nursery, If you wouldn't mid telling me the name.

 

[JackHammer]

Sooner is better than later getting a wintering over plan done

Heat size greenhouse do you use. Does it have electric nearby?

Our greenhouses are 8x6. We use a standard cheap electric heater plugged into a Thermo Cube Model TC-3: Thermostatically Controlled Outlet - On at 35-Degrees/Off at 45-Degrees which is plugged into the nearby outlet (it’s a gfic - it’s easy to get a plug in gfic). Used this method the last two years. No issues keeping the temperatures in the zone.

Azaleas aren’t the only plants we winter over. We’ve had many species from Chojubai to Mountain Hemlock to winter plant purchases hunkering down inside. .

cheers
DSD sends

I think I have a plan for winter.

My greenhouse is 10x16. It is near my garage so I can bring in power but I really don't want to.

My current plan is to build a cold frame in my greenhouse. It certainly will be very cold but I think that will minimize the number of days below freezing. I think 45 is not realistic for me without a heater but I am hoping that I will be close. Right now, I am still getting 95 in mid September, with the door wide open, so that is making me hopeful. In past years, i did get ice in my rain barrel but not too much.

My concern is that I will have a number of very hot days (full sun 60-80) and plenty of pretty cold ones (cloudy and snowing for 5 days 30-45). I will probably have about 200 gallons of water to help stabilize the temperature but I don't know how the plants will do with the wild swings.

 

[Glaucus]

So your local climate is colder than Geneva, OH? And you have it in a container, not full ground, So you need additional protection? Probably correct. But no way you need to stay at or above 45F.

If you want to maximize growth, you just want a longer growing season. You still want to get them to be pretty cold anyway. At least some 20Fs.

And yes, the risk with a greenhouse is that a warmer very sunny day will heat up your greenhouse, wake up your plants/trees, and then some frost hits them anyway.
You want a plant to experience near 32F/0C temperatures in autumn as quickly as possible. Then, when it is dormant and the truly cold weather comes around, you want to protect.
But when spring is coming and the extremes are over, it reverses again and you actually want to keep the plant cold and dormant for as long as possible.
And when it does wake up, you suddenly want to protect it from the cold once more.
It is a bit of a switcheroo.

Yours is a zone 5 plant. That's -20F. But that's in the ground as a landscape plant. If your winters usually only go down to 30F, then yes the main concern would be your greenhouse waking up the trees too early.
With temperatures of 30F in late winter, I would move them out of the greenhouse so they can experience those rather than the 60Fs.
The issue is below 10F daytime temperatures or prolonged periods below 32F.
Zone 5 is way colder than that, so some protection during the true cold snaps would be good.

This is my go-to article I always look regarding evergreen azaleas in really cold winters:

QBARS - v34n2 What About Evergreen Azalea Hardiness

Butler, Pennsylvania wouldn't be too far away from where you are at, right?

 

[snowman04]

So your local climate is colder than Geneva, OH? And you have it in a container, not full ground, So you need additional protection? Probably correct. But no way you need to stay at or above 45F.

If you want to maximize growth, you just want a longer growing season. You still want to get them to be pretty cold anyway. At least some 20Fs.

And yes, the risk with a greenhouse is that a warmer very sunny day will heat up your greenhouse, wake up your plants/trees, and then some frost hits them anyway.
You want a plant to experience near 32F/0C temperatures in autumn as quickly as possible. Then, when it is dormant and the truly cold weather comes around, you want to protect.
But when spring is coming and the extremes are over, it reverses again and you actually want to keep the plant cold and dormant for as long as possible.
And when it does wake up, you suddenly want to protect it from the cold once more.
It is a bit of a switcheroo.

Yours is a zone 5 plant. That's -20F. But that's in the ground as a landscape plant. If your winters usually only go down to 30F, then yes the main concern would be your greenhouse waking up the trees too early.
With temperatures of 30F in late winter, I would move them out of the greenhouse so they can experience those rather than the 60Fs.
The issue is below 10F daytime temperatures or prolonged periods below 32F.
Zone 5 is way colder than that, so some protection during the true cold snaps would be good.

This is my go-to article I always look regarding evergreen azaleas in really cold winters:

QBARS - v34n2 What About Evergreen Azalea Hardiness

Butler, Pennsylvania wouldn't be too far away from where you are at, right?

Great article with tremendous research behind it!

 

[JackHammer]

So your local climate is colder than Geneva, OH? And you have it in a container, not full ground, So you need additional protection? Probably correct. But no way you need to stay at or above 45F.

If you want to maximize growth, you just want a longer growing season. You still want to get them to be pretty cold anyway. At least some 20Fs.

And yes, the risk with a greenhouse is that a warmer very sunny day will heat up your greenhouse, wake up your plants/trees, and then some frost hits them anyway.
You want a plant to experience near 32F/0C temperatures in autumn as quickly as possible. Then, when it is dormant and the truly cold weather comes around, you want to protect.
But when spring is coming and the extremes are over, it reverses again and you actually want to keep the plant cold and dormant for as long as possible.
And when it does wake up, you suddenly want to protect it from the cold once more.
It is a bit of a switcheroo.

Yours is a zone 5 plant. That's -20F. But that's in the ground as a landscape plant. If your winters usually only go down to 30F, then yes the main concern would be your greenhouse waking up the trees too early.
With temperatures of 30F in late winter, I would move them out of the greenhouse so they can experience those rather than the 60Fs.
The issue is below 10F daytime temperatures or prolonged periods below 32F.
Zone 5 is way colder than that, so some protection during the true cold snaps would be good.

This is my go-to article I always look regarding evergreen azaleas in really cold winters:

QBARS - v34n2 What About Evergreen Azalea Hardiness

Butler, Pennsylvania wouldn't be too far away from where you are at, right?

This is really good news. I am a little west of Geneva and have a nearly identical climate. It sounds like the greenhouse will be plenty of protection without doing anything additional.

 

[Glaucus]

I am actually interested in breeding with zone 5 evergreen azaleas that survive -20F winters and therefore introducing them to Europe. It seems that Pride's azaleas have not gained that much traction.
I can only find 'Pale Lilac' as having online presence.
We have some other very winter hardy azaleas from NA like 'Herbert', 'Stewartstown' and 'Girard's Fuchsia', though.

Not sure if these azaleas show up often in nurseries in Ohio, Michigan, Pennsylvania that don't have a website.
Would be cool to try these in Poland, non-coastal Scandinavia, Baltic states, etc.

One more article on Orlando S. 'Lanny' Pride:

JARS v38n1 - Orlando S. ‘Lanny’ Pride

Scholarly Communication is a dynamic landscape, and we are continually evolving. Many scholarly communications activities have spun-off into their own departments, such as VT Publishing and Digital Imaging and Preservation Services, and Digital Library Development. Our focus is on supporting the...

scholar.lib.vt.edu

He, Girard and Gable did a lot for hardy evergreen azaleas in your neck of the woods.

 

[JackHammer]

I am actually interested in breeding with zone 5 evergreen azaleas that survive -20F winters and therefore introducing them to Europe. It seems that Pride's azaleas have not gained that much traction.
I can only find 'Pale Lilac' as having online presence.
We have some other very winter hardy azaleas from NA like 'Herbert', 'Stewartstown' and 'Girard's Fuchsia', though.

Not sure if these azaleas show up often in nurseries in Ohio, Michigan, Pennsylvania that don't have a website.
Would be cool to try these in Poland, non-coastal Scandinavia, Baltic states, etc.

One more article on Orlando S. 'Lanny' Pride:

JARS v38n1 - Orlando S. ‘Lanny’ Pride

Scholarly Communication is a dynamic landscape, and we are continually evolving. Many scholarly communications activities have spun-off into their own departments, such as VT Publishing and Digital Imaging and Preservation Services, and Digital Library Development. Our focus is on supporting the...

scholar.lib.vt.edu

He, Girard and Gable did a lot for hardy evergreen azaleas in your neck of the woods.

I had no idea and it looks like I stumbled into something really cool. I certainly saved all my cuttings and will check with some of the local nurseries for cold hardy varieties. I live in what is called "the snow belt". Wind comes from Canada over lake Erie and picks up water from the lake and then there is a rapid change in altitude that creates rain and snow. We have gorgeous summers but really brutal winters. -5 f with heavy wind happens several times a year. Due to the climate, there are certain things that do really well here like grapes and sugar maples (for syrup) but some things can't take the cold as I am slowly learning.

 

[Deep Sea Diver]

The first overwinter is the hardest.

The biggest source of concern for hardy trees is damage to the top hamper, fine branching especially. Trees in nursery soil seem to be a bit more hardy. Once trees are put in bonsai medium and styled and especially when they start getting finer ramification, they are quite a bit more sensitive.

Given you have a greenhouse, wind damage shouldn’t be much of an issue. Other key variables are Intense sunlight, cold, overwatering, dryness and fungus are important issues left. As far as temperature goes, we just open the doors when the temperature exceeds 45F. Works for us.

Good luck!
DSD sends