Welcome to BNut. I looked up Augusta Kansas before so I can give better horticulture advice. Your weather is probably similar to Wichita, Kansas, I'm assuming USDA zone 6, so at least once in a while your winters will get to -10 F or even a little colder. (that is -23 C for the rest of the world). No Satsuki hybrid will survive this. Some Kurume might, but you would have to research each individual hybrid to make certain its ancestry would make it hardy enough for your area.
There is no botanically significant distinction between Azalea and Rhododendron, All azaleas are Rhododendron. The gardener's definition is mainly based on whether flowers are in a truss, or single or low number of multiple at terminal bud of a branch. Intermediates between the types are common enough that the distinction is meaningless. Azaleas tend to have smaller leaves than truss forming Rhododendron. But there are some Rhododendron with leaves as small as the smallest of the azalea. Rhododendron is a huge group of species, with a wide range of traits. Only the species with leaves less than say 3 inches as a landscape plant are suitable for bonsai, with the smaller leaf species and hybrids being the best. A landscape plant with 3 inch leaves you ''should'' be able to get lead reduction to less than 1 inch, making it good for bonsai. Some of the Rhododendrons have coarse branching, and won't form fine twig patterns. The Satsuki have a nice fine branch/twig pattern.
Google John Geanangel, he's in Georgia, and is a much better azalea grower than me, he has a number of really informative videos on You Tube. He used to post here, still does occasionally, but has not had time to check in as often as he used to. Do check him out. His You Tube videos can really help you. His You Tube channel is
https://www.youtube.com/channel/UCxOEBT81SjIAoDQnpx49fbQ the Azalea videos are old, scoll back to 2011 or earlier. There are maybe 10 or so videos. Check them out. John is a well rounded bonsai artist, every video he puts out will teach you something, no matter the species.
So for Wichita area I would take two approaches.
#1. Look for azaleas sold in your local ''big box'' nurseries, or local specialty nurseries for azalea that are hardy in your area as landscape plants. These you will be able to winter by putting them in their pots in an unheated garage, tool shed, or other area to keep them out of the winter wind, and in the shade. So when they freeze, they freeze once, and stay frozen until spring. Freeze thaw cycling is rough on trees, so no direct sun in winter is critical. If the azalea is in a plastic pot, you can bury the pot to the rim in your garden bed, especially if it is in a shady spot. Mulch or cover as one would a hybrid tea rose, and dig up in spring. Easy. Low tech. Fancy ceramic bonsai pots are best if not subjected to below freezing temperatures or they may get broken. Good pots are frost proof., these tend to be expensive (north of $50 usd).
Encore hybrids might be listed as hardy for your area. Read labels to be certain this is true. I think they are fine for bonsai - but do differ from Satsuki. They have a somewhat coarse branch habit compared to Satsuki, and leaves will be larger, so plan a larger size bonsai - over 12 inches, or a design that does not need fine branching. Flowers are large, you will need to leave space between branches to make room for the flowers. If you don't compare them to 75 year old Japanese Satsuki, they are just fine as bonsai. They will no make the same refined image an old Satsuki will make. Encore hybrids are bred for easy bloom induction, which is why they bloom in Autumn. This will ''mess up'' the typical Satsuki azalea training Calendar of when to do what. In fact, you may find because of pruning work done in spring, your autumn flush of flowers on the Encore is heavier than the spring flush of flowers. If you have a collection that includes non-Encore types, you can take advantage of this.
Best reference for what to do when is the book published by Stone Lantern Press , by Callahan, I'm drawing a blank for the name, my copy is not in sight. Google Stone Lantern. Best English book on Azalea for Bonsai. Basically the techniques are the same whether it is a Satsuki or not.
Satsuki will grow in spring, pause, then flower, then resume growing. Kurume will flower first in spring, then grow. Most other species and hybrids of Rhododendron will flower first, then grow. When reading about Satsuki bonsai, remember that your non-Satsuki will respond more to the Kurume calendar of techniques.
The Northern Lights Series of Deciduous Azalea. This group of azalea hybrids is based on north american native species of azalea and is incredibly winter hardy. I only owned one for about 3 years, and never got it past pre-bonsai stage. The can work, don't try to make too small a tree with them. They will be frustrating, because the length of the internodes will be very long. You'll get a cluster of buds and branches, then a long stretch of wood with no buds or nodes, often over 6 inches between clusters of buds. or nodes. Aggressive pruning, alternating with letting it grow out a bit might bring it under control, but I have no first hand knowledge of success on this. I think more should experiment with this group. Some of the Northern Lights are good through zone 4, so are more than hardy enough for anywhere in the lower 48 states.
Other Rhododendrons - there are so many it is hard to generalize. PJM is a common hardy hybrid, leaves are a bit too large for bonsai, though some have used it. One parent of PJM is
Rhododendron dauricum which is very winter hardy, and has very small leaves, it is a nice dwarf plant, but tends to be shrubby, almost ground cover like. This species has been used as bonsai, some of the other hybrids from it are pretty good too.
Approach #2 - build, develop, create, or find suitable winter storage for less than fully hardy true Satsuki, or the sub-tropical florists azalea. I winter my Satsuki in an unheated, below ground well house. It used to hold the pump for the farmhouse well. It is below ground, and in late autumn quickly gets colder than 40 F (+4 C) through winter it never gets colder than about 29 F, (-1 or -2 C) It is about 6 feet x 4 feet, I store all my zone 6 and 7 trees in there. I put the trees in after a few frosts, but before the pots have frozen solid. In the well house I have a fan running, just moving air around 24 hours a day, anytime there are plants in storage. Fan really helps with fungus issues. There is no light. IF trees are held at or below 40 F, metabolism is so slow that light really is not necessary. In spring the well house warms up as soil temps warm up. There is a point at which it will get over 40 F, and trees will want to start to grow. At that point I either begin the ''in& out Dance", or I squeeze them into the orchid's light garden. Usually this period is no more than 2 weeks, then it will be safe to leave them out for the growing season.
If you have a cool greenhouse, most Satsuki are happy with a winter dormancy where nights are between 55 F and 32 F, ( +13 C to 0 C). Note anytime temperatures are above 40 F Satsuki need bright light. They will be active to some degree when above 40 F and so will need the brightest light you can provide. A cool at night south windowsill can work quite well.
About the ''Florist's Azalea'' - these are hybrids, often with Satsuki, hybridized for the floral industry. Like the Encore series they were bred to be easy to induce blooming, so that they could be forced on schedule for holidays. They usually have R. simsii in their background, which is a species from Taiwan, and is quite frost tender. If you pick up an azalea at a ''big box store'' or even grocery store, and it is not specifically listed as being winter hardy, then it is probably one of the Florist's azalea hybrids. These can be trained just like a Satsuki, but they will tend to bloom in late autumn or winter, or early spring. They need to be treated like a tender sub-tropical. They will not tolerate a hard freeze. Colors in this group are almost as good as the Satsuki. I have several and they really are turning out to be nice. I winter them in the light garden with the orchids. Or in the dark, cold wellhouse. Either works well.
So, those are the basic thoughts I had. Some of this was copy and paste from past posts. There is a lot of detail to learn to design a good azalea bonsai, but they are sure fun during the learning process. I love the flowers. Right now I have only 5 Satsuki, one Satsuki-Kurume hybrid, and 4 different ''Florist's Azalea''. Not a big collection, but as they mature it takes more an more time to wire them out properly. Only 3 of my Satsuki are developed enough to be in ceramic pots, and get wired out every year. The rest are in plastic pots, pre-bonsai at best.
Azalea horticulture - soil, water, and fertilizer are a complex topic. If your water quality is good, water with low dissolved solids, rain water is ideal. Some places municipal water is good, most it is not. If your water is good, or you are able to use rain water 80% of the time or more, you can grow azalea in just about any mix. If your water is hard water, with lots of dissolved calcium, more than 200 ppm as Calcium Carbonate, you will have to do a bit of work to develop a potting mix and fertilizer program that will work for you. Your municipal water department should issue an annual water quality report. Look to see what the total dissolved solids is, usually in ppm. and if possible the total alkalinity in ppm as calcium carbonate. Either of these two numbers is much more important than pH. Don't bother getting excited about pH until after you know either your TDS or your total alkalinity. When you know your numbers, get a hold of me and we'll talk.
I have never seen a large leaf variety reduce well. I recommend Evergreen types when starting.
