On 22/02/2016 18:12, Broadback wrote:
I know they have a tenancy to push themselves above ground, but many of
them are also laterally displaced. Who might the culprits be? More
importantly can I do anything to stop it?

Its usually birds, a number of different ones do it, always covered mine
until they had rooted themselves.

--
Charlie Pridham, Gardening in Cornwall
www.roselandhouse.co.uk
National collections of Clematis viticella & Lapageria rosea