Three rare Kalmia cuneata plants have been discovered growing at Squire's Garden in Milford, Surrey.
The plants were discovered during a cut-back of the overgrown expansive gardens at the back of the garden centre.
They are believed to be the only deciduous Kalmia in cultivation and the only National Plant Collection of Kalmia latifolia in the UK.
Group plant buyer at Squire's Tim Jacob said: "We've opened the entrance to the gardens right up - on removing a lot overgrowing Bamboo we came across the only three Kalmia cuneata in the country - possibly in the UK. It's a very rare and unusual variety."
Seven Kalmia cuneata plants arrived in the UK from North America several years ago. Four plants went to a garden in Scotland and three to Milford.
The Scottish ones have since died and now after being rediscovered, and with a lot of hard work from the team at Squire's, the Milford plants are on display for the public.
"We're hopeful a local nursery in Hampshire will be able to propagate it for us to enable us to have plants for sale in the next few years," adds Mr Jacob.