Many British oaks are hybrids of pedunculate and sessile strains. These are highly successful in the British climate but it is forbidden to sell the acorns for replanting. This is because the seeds are from wild flowers and it is an offence to sow seeds which are not EU approved. Because wild flower seeds are highly variable they do not conform to EU regulations on distinctness and uniformity. Approved seeds grown as fodder crops, such as red clover, are highly uniform and would compete adversely with natural diverse wild species.
Approved seeds are unattractive to wild insects such as butterflies.
Many approved seeds are not native to the UK, such as Albanian buttercup contained in approved mixtures. It is a criminal offence to market the seeds of hundreds of rare fodder and fibre plants and vegetables, many flavourful and disease resistant. These rare seeds have not been tested, an expensive operation only economic for commercial varieties. Ruyton Organic gardens preserve 800 varieties of vegetables that it is illegal to sell. It costs GBP2,000 to register a rare variety of vegetable.