I'm converting a small area into a food forest, and in the garden space is a granite boulder the size of a small car. The area was covered in ivy which I cleared, followed by a wood chip mulch on the exposed soil. The south facing boulder acts as a divider between a lower and upper area and I'm curious if people have observations they've made about the micro-climates that result from a situation like this. In particular -
Above & behind the boulder is an area where I imagine the soil will be kept warmer due to the thermal mass - are there some plants that thrive in warmer soil even though their above ground portions are more exposed? Until I establish a windbreak I can expect a regular cool breeze to take away any warm air.
In front of the boulder I imagine a radiant heat but likely less heat transferred to the soil - so the flip side of the above question - are there plants that thrive in warmer air but not necessarily warmer soil? Am I over thinking this, and the heat from the boulder should affect the area in front of it too?
The boulder is white granite and seems pretty reflective - could this a negative factor in its uptake of solar heat?
Plant recommendations welcome! :) This is in USDA Zone 8a.
I have boulders. Lots of them. Some VW size..some Mini Cooper size. I have extensive plantings in back of and in front of boulders. I use them more for shading than for heat retention and plant foxglove under their shade and in the crevices of their protection.
I do note that here I have great success growing lavender with its roots being protected by boulders. Out in the open I lose lavender. I’m in the colder drier PNW.
I plant horseradish on the North side of boulders for the root protection and it flourishes.
I plant Hollyhocks in the shade of boulders because I have learned they like their roots shaded/protected and the tops Sunnyside and hot.
I have a small forest of oregano that flourishes on top of the sunny hot side of boulders.
I’m sure there is heat retention there somewhere...I mostly enjoy my monolithic friends for their beauty.
Janet Reed wrote:I have boulders. Lots of them. Some VW size..some Mini Cooper size. I have extensive plantings in back of and in front of boulders. I use them more for shading than for heat retention and plant foxglove under their shade and in the crevices of their protection.
I do note that here I have great success growing lavender with its roots being protected by boulders. Out in the open I lose lavender. I’m in the colder drier PNW.
I plant horseradish on the North side of boulders for the root protection and it flourishes.
I plant Hollyhocks in the shade of boulders because I have learned they like their roots shaded/protected and the tops Sunnyside and hot.
I have a small forest of oregano that flourishes on top of the sunny hot side of boulders.
I’m sure there is heat retention there somewhere...I mostly enjoy my monolithic friends for their beauty.
Thank you - your suggestions are now my starting point!
Not experienced on boulders, but I imagine that the south facing aspect would help ripen fruit growing up it. I'm thinking figs, apricots, anything that might otherwise just struggle a wee bit to ripen with you.
I have a south facing slope on the side of our drive which I have terraced with our plentiful rocks and hope that the well drained soil will enable more tender herbs to overwinter better for me despite being rather exposed (photo taken in evening).
I don't have any wide experience or data to support this, but in my garden I have two citrus trees planted on the south side (northern hemisphere, zone 9b I think) of a large concrete retaining wall (with earth behind it). They grow very well, though those kinds of trees tend to grow well here anyway...