Pedigree Query

Are either of these toxic to horses? I have a spot at the end of our driveway I would like to plant some of these and the horses could possibly reach them to nibble.

Yucca is good for joint health/senior equine w/ pain

We have both yucca & pampas grass in an area horses have frequented for years. Never had a problem with the horses being harmed by the plants - but when I tried to plant more pampas grass last year they did a good job of trampling it.

Thanks for the replies.