Trees and bushes like yew, laburnum, privet and laurel are also poisonous. If there are oak trees overhanging the paddocks, the acorns will need to be collected, as these are also toxic. Many of the plants can be removed by hand or sprayed. Please wear protective gloves as these plants also harm humans. The plants need to be removed and burnt, as they become appealing to horses once they have wilted.
Weeds can be quite a problem as they compete with the grass for space and nutrients.
Nettles, docks and thistles need not be sprayed with chemicals. They can be controlled by clearing or cutting back. It's important not to cut back docks in flower, as these will self-seed. All the trimmings will need to be removed. Maintenance for spring.