- Welcome to Bonsai Nut, and possibly a life long hobby. Though "Not Yet !!!" is my answer to the question; "Have you been doing bonsai all your life?"
The Milwaukee Bonsai Society is a very active group, in Milwaukee. Unfortunately, their Oct 2 meeting was about preparing and storing trees for winter. Too bad you missed it (I missed it too, was travelling). The next meeting is November 6, Saturday, currently listed as TBD, most likely 9 am at the Boerner Botanic Garden, in Hales Corner. The November newsletter should be available by Oct 20, check back for details on the November meeting and the new newsletter.
The November newsletter will be at the link below once it is uploaded to the server, (I know the file naming pattern they use)
I am a member of the Milwaukee group. I keep Satsuki azalea, and some of my azalea have been in my care for more than 20 years. I started over with bonsai several times. Regardless, I have wintered my Satsuki type azalea and "florist's azalea" several different ways over the years.
If you have a basement, that is unheated or not heated as warm as the house, you can set up an under lights growing area, and you will be able to raise a large number of sub-tropical and cool temperate trees that need cool winter rest but can not tolerate a hard freeze. There are a couple marijuana grow supply stores in the Milwaukee area. Azaleas need about one half the light of a marijuana plant. An LED system for marijuana or tomatoes could be be used, just mount the lights to be about 25% higher above the plants than suggested for tomatoes. So if for tomatoes or marijuana they recommend the light one foot above the shelf, the light at 15 inches above the shelf would be 25% higher, and the light density per square foot would be about half compared to the mounting at 12 inches above.
Heck, for many years I used ordinary fluorescent shop lights (cool white T12 lamps, 48 inch fixtures, 2 lamps per fixture) mounted about an inch or two above my plants on a bench in the basement. The lamps were on ropes, I could raise or lower them according to the height of the plants that year. Lights were on a timer, 10 hours on, 14 hours off until February, then 18 hours on and 8 hours off until it was safe to move them out in spring. Have a small fan blowing across the area with the trees. A computer cooling fan will do, or a cheap fan from Walmart. The air movement keeps roots healthy, as air moving across the soil helps air to penetrate the soil.
Modern LED lamps are very energy efficient and run much cooler than the old fashioned fluorescent tubes.
An alternate method is you are lucky enough to have a decommissioned well house. At my current home I am lucky enough to have a well house. This is an underground room, that is deeper than the frost line. I can access it through my basement. It is where the now filled in well head was located. The roof of the well house looks like a patio in my back yard. In winter it falls to the same temperature as the ground at 5 feet below grade, roughly 32 to 40 F. Temperature is very constant even in the coldest of winters the well house stays just barely above freezing. I wait until end of November, then move all my less than fully winter hardy trees into the well house, including evergreen azalea. The well house has no lights. I have a fan to keep air moving in the room. I close the door, it is totally dark. I check once a week to see if they need water. As long as the temperature is below 40 F, there is no need for light. The metabolism of azalea, pines and other trees is so slow at 40 F or colder that very little stored sugars are used. Everybody comes out in spring.
Worst choice, or rather most difficult choice is wintering your Satsuki on a windowsill in the house. The cool from the glass will be enough to simulate a cool rest. It will be difficult keeping the plant humid enough. But it can be done.
If you can, come to the next Milwaukee Bonsai Society. Our club's member Rick W, Judy S, myself Leo S, Steve C, and Irene H, and Brian S all have satsuki azalea and each of us winter's ours differently. Rick W and Steve C use a greenhouse heated to barely above 40 F at night. I use the well house currently, Irene does the windowsill routine. I forgot how Judy does her's. Most of this list make just about every meeting. Hope to meet you.