Toxic plants \ shrubs for cows and horses

[Listentomyheart]

My garden backs onto a field with cows and horses. They can stick their heads over into my garden but can't get physically in (barbed wire). I was wanting to plant in front of the barbed wire but I'm struggling to find info as to what not to plant etc. I don't want anything that could make the animals ill obviously. I never see the farmer to ask them. It wouldn't be a tall border maybe 2-3ft max as we like to see them. I love my plants and this boundary is approx 18ft so lots of potential for lovely plants. I have lots of meadow seeds but wary of sowing them just in case. Can anyone advise please?

I should add, I like cottage garden feel aka stick any old plant in and hope for the best.

Personally I would plant a long hedge as a backdrop, put a mixed border in front. Hawthorn is the normal choice with livestock because it grows rigid. They may graze it from their side but that means you only need to trim your side and the top. It holds its shape

Definitely a hedge. Otherwise you’re planting a buffet 😆

Hawthorne, blackthorn, ash, elder, holly, crab apple (and other fruits), willow, birch, Rowan, dog roses are all fine to go in a hedge. I’m not sure about oak as the acorns are poisonous to sheep.
Yew is extremely poisonous. Lupine are also poisonous.
Cottage garden type plants that are ok are roses, poppies, lavateria, those spiky artichoke plants, poached egg plant, any fruit bushes. The ok plants will get eaten if they can reach them. Most animals don’t eat any poisonous but there’s always a stupid one.