Paul Hadley of DLF Seeds & Science (formerly DLF-Trifolium) spoke to landscape architects about how to ensure the grassland thrives at a Landscape Institute Midlands event at Whiting Landscapes last month.
Hadley explained how the grassland could be better delivered, covering soil type, local environmental and site conditions, root zones, wild flower seed production and selection, with a focus on the growing-in phase and ongoing maintenance.
Many landscape architects who work on large housing developments are responsible for specifying mitigation schemes that include native origin wild flowers and conservation grassland, and need to ensure that species-rich mixtures will thrive. But both specifier and supplier need to consider how they are selling the grassland concept to clients, who often do not have a good understanding of what they are planting, said Hadley.
"Unrealistic expectations of how these mixtures will perform, and the length of time they will take to establish, can often determine the project a failure way too early in the life cycle of these kind of mixtures," he added.
Contrary to what many developers seem to think, there is "nothing easy about establishing wild flowers at all", he said. Hadley explained that many developers are required to sow species-rich grassland mixtures as part of a mitigation strategy that is a condition of their development gaining planning consent.
"The perception is out there that you can just throw the seed down and walk away. That often leads to disastrous results, through no fault of the seed or the contractor or the specifier," he said. Developers often expect an "instant chocolate box look" when in fact it can be "years before these mixtures look their best".
Hadley also explained to his audience the processes involved in producing UK Native Origin wild flowers including the issue of seed purity. "There are no actual seed purity standards for wild flowers, unlike grasses, meaning seed can be sold containing significant amounts of plant and other debris - thus leaving the supply of such mixtures open to abuse by the unscrupulous supplier," he said, warning that "if a mixture is cheap, it's cheap for a reason".