I have a large amount of recycled concrete from a slab that was broken up, and I am using it to make terraces on a southwest slope in the maritime PNW.
So, the conditions are hot, dry in summer, but wet in winter, zone 7, alkaline, and vertical. I am looking for suggestions on how to build the walls so that I can grow small plants in them, and ideas on what plants would do well or be particularly interesting or attractive.
I am thinking already about plants such as Saponaria, Alyssum, Sempervivum, stonecrops, and a particular kind of Corydalis that is known for growing well on walls, Corydalis lutea. I'm new to rock garden plants, though, so I'm open to your suggestions!
Difficult to give guidance Gordon as the style of rock work to adopt is very much a personal thing. Ian Young of The Scottish Rock Garden Club uses, very successfully, pieces of concrete building block in his troughs . There are many different rock work schemes that might give you useful ideas and ideas for plants to use here http://www.srgc.net/forum/index.php?topic=4656.0 and here http://www.srgc.net/forum/index.php?topic=3537.0
I have used a lot of (recycled) concrete in my garden here at the west coast of Norway. I suppose the climate is similar but yours is probably a bit warmer in summer. It can be rather dry here in May, June and July but not very hot (max 28C, usually not more than 25C).
I find that some Primula species and particularly some Saxifraga species do very well. They even self sow a lot.
I have faced some of the concrete with ordinary rocks to get variation.
This is my shed roof. The tiles are concrete and I have covered them by a thin layer of sandy soil and lot of rocks (also pieces of concrete).
This is also my shed roof.
This is naturally occurring Saxifragas in calcareous rock.
Thanks for these ideas. I love the crevice gardena and troughs, and Saxifraga and Primula do look like well suited plants.
Aesthetically, I am thinking that it would be wrong to try to make the recycled concrete look like natural rock, so the "old decaying ruin" effect would be what I want to create. As if an old abandoned wall had been colonized by nature.
As for plants, anything that is at home in limestone crevices would be worth trying. PNW natives Sedum spathulifolium and Sedum oregona are on my list.
Yes, those look good, Toole. Do you know what some of the plants are? I see what looks like a white-flowered Corydalis, and maybe a violet-flowered Saxifraga. This does show, though, that once the plants get established, you hardly notice the concrete pieces.
I think the white Corydalis is C.ochroleuca.
The yellow one is Corydalis.lutea.
Violet flowering plants are Haberlea rhodopensis.
Looks like one of the wood anemones, Anemone nemorosa cascading from the top of the wall down behind the large rock.
Name for the daisy like silver green growths escapes me for the moment.....