In addition to alerting visitors to the dangers of non-native species such as Japanese knotweed and giant hogweed, the specialist nursery urged landscapers, local authorities, designers and landscape architects to examine the source of all native plants for authenticity.
BWFP marketing manager Ian Forster said: "It is not just species like knotweed, it's other species that are cross-pollinating.
"A true bluebell is like a bent wrist with flowers hanging off the base," he explained. "Those species are very important.
"But the Spanish bluebell is now cross-breeding with our British variety and is in danger of wiping it out."
He added that BWFP would like to see a voluntary planting policy introduced by those involved in designing open spaces to ensure the survival of indigenous species.