Sedley Place will work with Briers in "brand guardian capacity, with a remit to define and deliver positioning and marketing strategy as well as core branding across all communications channels".
Jackie Eades, founder and managing director at Briers, said: "Consistent messaging and branding is a vital element of our overall marketing plans as we seek to grow the business even further in a competitive marketplace. Sedley Place clearly understands our specialist market and our needs as a brand, not to mention the fact that the team chimes with the way we think.
"The agency’s expertise makes it an obvious choice to act as brand guardian. Everything we do and say has to be consistent, whether we’re communicating with expert professional gardeners, casual potterers or people who want a pair of fashion-forward wellies."
Ron Cregan, business director at Sedley Pace, said: "The Briers board has effectively appointed Sedley Place as its marketing team, and it’s intensely absorbing to create an effective strategy for a challenger brand in a growth market. We developing clear, coherent thinking that will be backed by inspirational creative ideas."