Guernsey Clematis is now an official supplier to the Royal Family.
The nursery has received recognition from Prince Charles.
The grower - which has won multiple gold awards at the Chelsea Flower Show - has been granted a prestigious Royal Warrant.
Founder Raymond Evison has described it a a 'great honour and privilege'.
Royal Warrants are only bestowed on companies who supply products to the royal household over a number of years and who reach the highest levels of sustainability in their production.
Raymond told Island FM:
"I knew from other people involved that if we've been a regular supplier to His Royal Highness for five or six years then we were invited to apply for a Royal Warrant. That meant going through various stages and filling in a very long form about sustainability.
This about sustainability in the production of our plants - such as the reuse of water, the reduction in the use of peat and chemicals - the business practices and the social responsibilities with staff.

"We are delighted to be granted the Royal Warrant. It says HRH is very happy to grow our Clematis in his garden."

Talks ongoing to enable Guernsey ferries to access St Malo
"No shortage" of flu jabs for Guernsey vaccination programme
Both winning CI Christmas Lottery Tickets sold in Jersey
Guernsey women's murder trial "unlikely ever to resume"
Guernsey actor to reprise Doctor Who role for Boxing Day Dip
Aurigny to fly between Guernsey and Jersey next year
Review into healthcare complaints in Guernsey to go ahead
Former CI Co-op boss awarded more than £3m