Picking wildflowers and the law
Contrary to widespread belief, it is not illegal to pick most wildflowers for personal, non-commercial use. In a similar vein, it’s not illegal to forage most leaves and berries for food in the countryside for non-commercial use.
Legislation under the Wildlife and Countryside Act (1981) makes it illegal “to uproot any wild plant without permission from the landowner or occupier” in Britain. The term ‘uproot’ is defined as “to dig up or otherwise remove the plant from the land on which it is growing”. Picking parts of a plant (leaves, flower stems, fruit and seed) is therefore OK, as long as you don’t remove or uproot the whole plant. Similar protection is given to all plants in Northern Ireland under the Wildlife (Northern Ireland) Order (1985).
However, you should not pick any plant on a site designated for its conservation interest, such as National Nature Reserves (NNRs) and Sites of Special Scientific Interest (SSSI's) in Britain and Areas of Special Scientific Interest (ASSI's) in Northern Ireland. Permission for picking from these sites requires prior consent from the appropriate statutory conservation agencies (English Nature, Natural Resources Wales, Scottish Natural Heritage or the Environment and Heritage Service, Northern Ireland). It is illegal to pick, uproot or remove plants if by-laws are in operation which forbid these activities, for example on Nature Reserves, Ministry of Defence property or National Trust land.
In addition, both the Wildlife and Countryside Act and the Wildlife (Northern Ireland) Order include a list of highly threatened plants that are especially vulnerable to picking, including plants like Deptford pink, alpine sow-thisle, wild gladiolus and several orchids and ferns (as well as fungi, lichens and bryophytes). No part of these Schedule 8 species can be intentionally picked or uprooted without a licence from the appropriate statutory conservation agency. These plants are also protected against sale. A full list of the plants, fungi, lichens and bryophytes on Schedule 8 is available here.
Finally, picking of wildflowers is also specifically covered under the 1968 Theft Act (England and Wales): “A person who picks mushrooms growing wild on any land, or who picks flowers, fruit or foliage from a plant growing wild on any land, does not (although not in possession of the land) steal what he picks, unless he does it for reward, or for sale or other commercial purpose”. However, the same restrictions apply to picking on land designated for its conservation interest as described above.