Moss Blog

February 25, 2010 Life on the rock.

Some species of mosses can grow on rocks even in the sun. In the FAQs I mentioned the limitations of growing full sun mosses but if you buy a rock already populated with sun loving mosses then you just need to know how to give it a proper home.

I once visited Hoerrs, a large nursery and landscaper in Peoria, Illinois and was surprised to find some really big tufa rocks that had all kinds of alkaline loving mosses and lichens. The biggest rock was more like a boulder and probably weighed at least a ton (907 kg) maybe two tons. This was not some recently excavated rock. This rock came from a natural setting where mosses and lichens had been growing on that rock for many, many years, possibly hundreds judging by the types of lichens also growing on the rock. I asked a landscape architect to come out into the stone yard and look at her million dollar rock. Hopefully the rock was placed in a part sun part shade setting where the mosses and lichens could survive.

Now tufa rocks are primarily populated with alkaline loving mosses and my goal last year was to find a nice sandstone rock with Grimmia genus mosses as well as some neat looking lichens. As you can see I finally found my rock. This rock came from Quint City Stone in Davenport, Iowa. The moss in the center of the rock is a Grimmia species and the moss in the lower left is Hedwigia ciliata which I added.

Now both of these mosses can handle full sun. But their appearance is dramatically different on a hot dry day then on a day when the mosses are hydrated. The picture above is when the mosses are fully hydrated.

It is best to give even a full sun moss some shade because it will grow and look better than if it is in full sun all the time.

Hedwigia ciliata I have seen growing in full sun on the southern exposure of a granite rock in central Indiana. Yet when I go on vacation to the Ludington, Michigan area I find it growing on the cabin roof which is under tall oak trees in the shade.

Hedwigia is a tough moss. Yet when it falls off the roof of the cabins at the small resort where we stay it dies on the sandy soil even if it gets enough moisture and sunlight. Hedwigia does not like to grow on any kind of soil. However for several years I have grown Hedwigia ciliata on the artificial mat system in the shade on the ground and it looks great.


Red sandstone rock with Grimmia species moss in center, Hedwigia ciliata moss lower left and several lichen species all over the rock