I'm hoping to get some information for creating rock garden soil, and possibly some ideas on plants for the area. I live in a river canyon, with rocks everywhere. I also have large boulders that either landed together, or were piled together, and I would love to create a rock garden area in and around some of those boulders. I have an endless supply of rocks to create nooks and crannies for plants, but I have an extreme shortage of soil to fill the areas in so that I can put plants in there.
I have some semps and sedums that I plan to move to these rock garden areas to begin with. This area is outside of the fenced in yard, and I'm overrun with deer out there, so anything planted has to be deer resistant. I have lots of iris growing out in this area, and the deer haven't touched the iris in 3 years, but I need something other than iris in the new rock garden area. Also, short plants will be much better for this area, since I don't want to obstruct my view.
I've successfully grown both semps and sedum in my yard, which oddly enough has very few rocks in comparison to outside of the fenced yard, but I'm really not positive on what is perfect for either of those in a rock garden setting. I amended the clay soil in my garden for the semps with a lot of large sand and small pebbles, and they seem to love it. I've also planted semps in potting soil in a very shallow whisky barrel, with maybe 3 inches of potting soil, and they've grown like crazy in there with almost no additional water given to them. The growth rate may be due to the fertilizer, but they have been blooming, so I'm not sure that it is actually a problem having the fertilizer mixed in. It also could just be that particular semp, which I can't remember the name of, grows like crazy wherever it is. I'm in zone 6b/7a in north central Idaho, with blazing hot summers at times (up to 116 degrees for a few days during a couple of summers in the last 7 years), and harsh winters at times (covered in solid ice for almost 3 months one winter), but it's usually a little more on the mild side in comparison. Last summer never got above 100, but it did stay in the upper 90s for a long while, and the occasional short stretch of low 100s is normal during summer. My property faces south, and there is zero shade in the area I want to plant, so plants need to be tough! It's also not in an area that will be easy to provide water to on a regular basis, though I will certainly do that until plants settle in and get established, and I can do that occasionally as needed. I do not want to have to be watering anything out there weekly though, as it's just way too much work for me, and I'll possibly run into a rattlesnake or two, which I'm not fond of doing.
Specifically, I need information on creating the proper soil mix for the plants. More than likely, I'll have to purchase whatever "soil" I can find at Home Depot or the farm and ranch store and amend it to fit my needs. I know they sell something called top soil, but it's basically steer manure that has no soil in it because it hasn't even composed. It's nasty stuff. They also sell Miracle Grow garden soil, which appears to be partly composed wood with slow release fertilizer mixed in. That stuff works fine mixed in with the native soil for a regular garden, but I don't think it would work for a rock garden, especially on its own. Maybe I'm wrong though? It would be great if that would work, because it's readily available where I live, but I have pretty much no native soil to mix with it. Yes, I have some in my yard in the form of mostly clay, but I'm not willing to dig a hole in my fenced in yard. There is probably a rock garden mix that is commercially available, but I've never seen one here. I do think that the garden soil/partially composted wood might be a little too rich for what I would eventually plant there anyways, especially since it contains fertilizer, but again, I could be wrong about that.
Any suggestions on what to do will be most appreciated! I have no idea what to do in order for this to be successful to any degree!
