I have a beautiful Rose of Sharon I planted 15 years ago. Now, even after cutting it back, it's blocking view and am wondering if there was a way to dig it up and put it someplace else. I know to wait till fall and that it's not something I can do on my own. Suggestions? Recommendations?
I'd be inclined to take semi ripe cuttings in late summer/fall - they root quite easily, and once they've got to a reasonable size, you can then remove the one you've got and plant one of the cuttings in its place, or just plant one or two elsewhere.
If your Hypericum has been in the ground for 15 years and it's big enough to block the view, it's likely Hypericum 'Hidcote' - you can try digging up a portion with roots attached, but trying to move the whole thing may not be successful. Taking cuttings first, then trying to move it if you want is a better idea. Information on semi ripe cuttings and how to do them here: Cuttings: semi-ripe.
Its just occurred to me that what we Brits use the common name Rose of Sharon for is Hypericum, but in the USA, rose of sharon is what you call Hibiscus syriacus, along with Hypericum and one or two other plants, so this information probably doesn't apply. Which plant are you talking about exactly?
What view is it blocking? I would leave it right where it is and start thinning this shrub. If you 'head' it by cutting it down you are only energizing it to get denser. To thin a shrub you prune out all the little branches, dead stuff, and essentially make this shrub into a small tree. At 15 feet it most certainly qualifies. At 15 feet, even transplanting in winter you'd have at the most a 25% chance but I think it would be less.
A small tree would provide framing and enticing 'peek a boos' of your yard. While at the same time giving the viewer a foreground view that adds to the depth and perspective of your yard. That shrub is worth its weight in gold to expand one's views if managed correctly. I can most certainly help with pruning over the internet. Need pictures of course. Sharp bypass pruners, pruning saw and alcohol.
If you are really set to try moving this shrub, you can start right now by digging a foot deep and wide trench around a root ball you could manage to move via dragging it on a tarp. Perhaps you could find someone with a big forklift to help?
To have any success at life after major surgery, that trench will help your plant put out more feeder roots within the root ball it will have to survive with until after planting and after the winter. Dig the trench around the base of your plant's trunk at a minimum 2' radius. If you have access to a forklift to use this early winter, before the ground is frozen then make it 3' radius. Fill the trench with straw and soak with water. Purchase mycorrhizae fungal spores from a decent nursery to sprinkler in the trench and over the root ball. Save some for after transplanting. This greatly helps the roots to be able to take up water and chemicals necessary for photosynthesis.
Your root pruned shrub will need to have the top growth thinned and headed. Divide prunings into 2 or 3 sessions this season because doing too much in one session >30% is major stress at the same time as the roots are making sense of a smaller area with which to derive water and chemicals to do the job of photosynthesis, which feeds the roots to survive winter and the move. I would only prune <20% each session. You are in fact 'root pruning' so the top growth needs to be reduced as well
This will only ensure 50/50 chance. I'd like to see the view you are discussing and this gorgeous 15' shrub. Think of 'Bonsai', or a multi stemmed patio tree framing your view. Send pictures. If you had a company 'pluck' this shrub out of the ground, they would do all the same things I've explained. Then they would sell this shrub for...easy 4-5,000 bucks.