Well, you could sow annual wildflower seed mixes. Then you'd have the pasture full of flowers, and they'd reseed and you'd have them again next year.
If I had a pasture, I'd sow wildflowers in a hearbeat!
A plant in the alley
I found another list of poisonous plants in case you guys are interested.
http://en.wikipedia.org/wiki/Poisonous_plants
Josephine.