Retailers have been given a 12-month warning to sell their banned stock from 31 August 2016. This allows them to carry out existing contracts with plant suppliers. The ban is officially in place from August 2017 onwards at retail outlets including garden centres.
Despite this, Water hyacinth (Eichhornia crassipes), Yellow skunk cabbage (Lysichiton americanus) and Cabomba caroliniana can still be readily found online at £5-£10.
Curly waterweed (Lagarosiphon major) is the only aquatic plant on the list of banned plants which is no longer available to the market.
The Ornamental Aquatic Trade Association (OATA) is trying to combat the issue by suggesting alternative plants for retailers. However, it is still cautious about other water plants which may be offered as substitutes.
OATA chief executive Dominic Whitnee said: "We ask the industry to act responsibly and not seek to replace any of the banned plants with one that has been flagged up as causing an issue. We have suggested some alternative plants to help the industry replace those that can no longer be sold."
The association said that retailers should be aware of other plants which may be banned in the future because they could potentially be invasive. These include the North American Water milfoil (Myriophyllum heterophyllum) and Egeria densa.
Whitnee added: "This is another example of where the industry can act responsibly by not selling this tropical plant for ponds. It is not suitable for use in garden ponds because it tolerates cooler water too readily and it should only be sold for aquariums."
OATA's Pauline Davey added: "Water hyacinth should not be on the list because it cannot survive a British winter anyway. It will die out eventually because it won’t be able to last the cold weather."
OATA suggests to replace the banned stock with British native water plants which are properly suited the climate.
#water hyacinth alternatives: water lettuce and water soldier.
#curly waterweed: any British native submerged plants
#yellow skunk cabbage: white skunk cabbage
#Cabomba caroliniana: Cabomba aquatica