Viewing post #527880 by dirtdorphins

growitall said:

It's sort of complicated (but fortunately, growing some desirable plants isn't ) and I'm no expert, but it's probably safe to say that for most rock garden/alpine plants, it's really the soil conditions (primarily drainage) that are important, not the presence of rocks per se.
The wetter/more humid your climate, and the more prone it is to winter wet especially, the more important drainage becomes (hence the popularity in wet areas of alpine houses - the purpose of which is usually not insulation but primarily to shelter plants from too much water!)
As shown, sand beds and gravel beds can be great for growing plants that need good drainage and lean conditions - no rocks are required at all... in fact, to be honest, unless rocks are used skillfully, as in the incredible crevice beds I showed, they can actually reduce one's planting space quite a bit.... they take up a lot of room! However, the presence of rocks allows one to create structure and build up the garden (elevating it above the surrounding area improves drainage), and some rock garden/alpine plants do like to grow best with their roots in deep crevices between rocks. As you noted, rocks also allow one to create shade and shelter. And I suppose they help people to identify it as "a rock garden"... and I just like rocks, as many of you have said too!


The tufa is all natural, bought from Rocky Mountain Tufa whose quarry is in B.C.. The rocks were basically manhandled into place (we did it all ourselves with no machinery - DH had to move the biggest pieces from the first big order that were beyond my abilities; I avoided really big rocks in the second order!) The tufa rocks were mostly place on end for height. The main thing was the process of packing a lean soil mix in between the rocks, to stabilize them all and provide the growing medium and the fill in crevices. I'll post some photos of the process.
Keep in mind that I'm not saying this is the best or only way of doing it - it's only how I did it.

Well said!!!

For me, the winter wet issue is really a spring wet issue--when it actually rains and all the snow melts and everything gets soggy. And when the ground is still frozen beneath the first few inches then we can get some serious sog. For example, delospermas survive the winter well for me but die in the spring if I plant them in my crappy clay. Conversely, in elevated free-draining areas, they do well.