|What could be the problem? Pests? Too little/Too much water? They also don't seem to be growing as fast as these plants typically do. What can I do?|
|Browning at the base and slower than normal can be a sign of several different problems such as poor rooting due to being pot bound at planting time, planting too deep, overwatering, poorly drained soil, or possibly a pest or disease issue. I would suggest you work with your county extension to try to obtain a firm diagnosis of the cause and then once you know that, you can determine how to proceed. There is contact information at http://www.hgic.umd.edu/
Good luck with your Leylands!