I have a bit of an odd inquiry and not sure where the best place to post it would be, so I figured I would try here. I have numerous recently built retaining walls and steps which are made using Allen Block (some pics below). My question is, to give an impression of age and character I have added sedum amongst any cracks I can find but would also like to incorporate some Lichen as well? Is this possible? If so, how do I go about finding some Lichen and then "planting" it on to my walls and steps? Will Lichen do okay on a porous concrete based product? Any suggestions as to which Lichen may do well and look good in this area? Thanks - any advice you can provide would be very much appreciated.
Some one once told me that if you painted statues (concrete) with milk it would encourage them to go green ie. moss. Don't know how true that is. Might be worth an experiment. Liz
I have used moss blended in a blender with sour milk and "painted" my brick paving stone cracks with good results - but not sure if that trick would work for Lichen as well, may be worth a try.
Probably not. I think lichen tends to like it dry. Different plant altogether. You will probably have to wait for father time to do his bit. After all lichen is one of the things that breaks down rocks. If it likes your nice new shiney wall it may try to colonize. Have you thought of trying rockery plants that hang down from top. We always had masses of rockery plants hanging over a bluestone retaining wall (large basalt rocks cut by convict labour in the early white history of Aust.) Were very cheap to buy once but now cost an arm and a leg. I meant Alpine type http://www.alpinesandgrasses.co.uk/06alpinesA.htm Liz
Thanks Liz - love the history behind your retaining wall, and it sounds magnificent. We have started with some rockery plants and even have a variegated Ivy in one corner where we do not care if it takes over! I was not sure whether Lichen would break down the concrete blocks, so it probably is something best left alone for Father Time :-)
The airborne-distributed lichens will colonize on their own. They tend to be fairly substrate-specific. As for breaking down rock material - well, yes, but you wouldn't be able to measure the difference in our lifetimes and likely not for a few hundred generations before being able to see a noticeable difference.
