Bracken is a common fern that grows throughout Britain and you must be careful it does not dominate your grassland. The whole plant contains several toxic substances, some of which remain after cutting and drying. The root of bracken is five times more poisonous than the fronds.

Although fruit trees are not poisonous at all, we have included fruit trees, because during the autumn when they are full of fruit, the fruit can cause digestive upsets in donkeys. We recommend that the trees should be fenced off to prevent donkeys gorging themselves on the fruit.

Hemlock is very common to Britain and is generally associated with damp places, and often found in the hedgerows. Hemlock will grow to 6ft in height. It has large fine cauliflower type flowers in abundance on each stem. Poisoning is most likely in spring when young leaves are eaten with other herbage, or on poor pasture.

All varieties of horsetail (mare's tail) is poisonous but field horsetail and marsh horsetail are most likely to cause poisoning. It is a perennial plant with creeping underground stems from which green, jointed, upright stems grow in spring. Poisoning is most likely to occur when horsetail is present in hay or bedding.