Here’s the thing about Rhododendrons.
1. I honestly believe they could make a motivated grower fairly wealthy. Nobody is growing them, especially in zone 4!
2. Rooting them is tricky and best done over bottom heat in the winter. Warm roots, cool tops, 45 degrees or lower.
They hate wet feet, they hate heavy soil. My place would be perfect for them, sandy soil, but at this age they would be a multi year project and I’m just not looking for that kind of commitment.
But if I were, I’d buy about 3,000 rooted cuttings, $2.00 each, line them out in beds 8″ apart, mulch them, water as needed. Pinch them so they develop nicely then take as many cuttings as I could year after year after year.
Then I’d probably line them out in the field, get them to 30″ size and sell them to landscapers for a lot of money. At least $30 each but maybe keep them longer just to get the cuttings, then sell them for $40 each.
I’d hire a professional digger to get them out of the ground.
I’d only do about 4 or 5 varieties.
I could build a multi generational business with those five plants.
I have more to add to this post as soon as I get some photos etc.