Hillier Nurseries bagged a record 65th consecutive gold with their centrepiece ‘Adventures in Gardening' exhibit.
Managing director Andy McIndoe said: ""I am absolutely delighted with our medal result. "Staging the Hillier Chelsea exhibit is a fantastic team effort, and so to win a 65th consecutive Chelsea Gold medal is a great thrill for the entire Hillier group.
"We had a mighty battle with the elements this spring, and all credit goes to Ricky Dorlay, who brought all his 45 years' Chelsea experience to bear in preparing the Hillier plant material."
The prestigious President's Award went to vegetable grower Medwyns of Anglesey.
Owner Medwyn Williams led a team covering three generations to bag the top prize at his first show in five-years.
John Woods Nurseries' also took gold for their Upwardly mobile exhibit, part of the Sun's generation gardens feature.
The company was exhibiting for the first time in a bid to promote its stockists to the general public.
Managing director John Lord said: "Upwardly mobile shows how easy it is to create kerb-to-frontage appeal to a home with original front garden design.
"We've used plants that are happy in different types of soils and situations, for example, to help inexperienced gardeners understand their options. We're delighted that the judges recognised the design principles, the planning and the sheer hard work that were necessary to bring this feature to life."
The display will be relocated to the National Garden Centre at Capel Manor College in Enfield at the end of the show.
Peter Beales Roses won its 18th Chelsea gold.
Exhibit designer Ricahrd Beales said: "Growing roses amongst the branches of trees is a concept that is often overlooked by gardeners, but it is one of the most natural ways of growing this type of rose. We are thrilled that the Chelsea Flower Show judges agree that this stand and new style of display is worthy of the prestigous gold medal."
Returning to the show after a two year break, Claire Austin's exhibition of 40 bearded Irises was also awarded gold.
She said: "I am so excited to win Chelsea Gold. It really is the ultimate accolade for every grower, and I am absolutely thrilled. It definitely makes all the effort behind the scenes worthwhile."
Burncoose Nurseries also celebrated, after netting their 21st gold medal at Chelsea.
Burncoose Nurseries owner Charles Williams said: "We are delighted to have been awarded a Gold Medal at RHS Chelsea, bringing our total tally to 21 Gold and eight Silver Gilt.
"The whole team has worked incredibly hard this year and they have had to contend with harsher than normal weather conditions over this winter. They have created a well designed and fantastically inspired garden which has a great story to tell.
"Every year the standard of exhibits and gardens improves so we are very pleased we have been awarded Gold again this year. I'd like to thank the team for all of their hard work and also our sponsors, Terra Firma Capital Partners, for making the Burncoose exhibit such a success.
Dorset based Knoll Gardens were also honoured with gold for their display of ornamental grasses.
Owner Neil Lucas said: "This is going to be an exciting year for us at Knoll Gardens, and it is wonderful to have been awarded another Chelsea Gold Medal to start the gardening year in style.
"Everyone recognises that plant quality required to win a Gold Medal at Chelsea, but I think they sometimes forget all the people that work continuously to maintain that quality. "