I have searched in your Poisonous Plants book, (this CD rom is a very valuable item for me as I now own my own land, so am in a better position to improve pasture, or at least mitigate for its shortcomings and avoid planting pitfalls) and I have seaarched on the search facility here on the forum but cannot find any reference in either to Leylandii being poisonous - yet I seem to remember that it has been cited (I thought by you) as causing birth defects in horses if ingested in sufficient quantities. Do you have any knowledge of this?
Jacquie, do you mean 'leyland spruce'? There is no genus 'Leylandii', that is the name of a species or variety. I need more accurate info from you before I can respond. -- Dr. Deb