Buddleja (alternative spelling “buddleia”) is commonly-known as the Butterfly-bush, and is a deciduous shrub that can grow up to 5m tall. It is particularly problematic because each flower can produce over 40,000 seeds which can lay dormant in the soil for years. Even though it is classed as invasive in the UK it is still available to buy for people who want to plant it in their gardens. It has been found catchment-wide in the River Thame.
It is a very attractive plant which attracts many butterflies. It is this feature which encourages so many people to purchase it, but you can help by recommending native ‘butterfly loving’ plants that would naturally occur in the UK.