The 12-centre Hillier group has reached £5m in plant sales, which remain its top category. Managing director Chris Francis said Hillier has to keep its reputation as a plants-based group, with only the best-quality plants and best range acceptable.
But Francis said he sympathises with 22-centre Klondyke, which has plans to cut planteria size at its Carlisle centre and has built a more compact planteria at its Garforth centre in Leeds. Francis said Klondyke often has worse weather to deal with in the north and Scotland, and he might have similar ideas were Hillier's centres further north.
In an interview to be published in the new year, Klondyke's incoming chief executive David Yardley said: "Having a big planteria is not the right thing. You can get two or three deliveries a week so don't need one. Big garden centres mean big overheads and don't make the money. It's better to have a compact garden centre with the ability to expand and not start with anything too big."
Outgoing chief executive Bob Hewitt added: "A lot of our planterias are too big. A lot garden centres are finding that. (Flagship) Carlisle is too big, so we'll cut it and add a shed concession. It makes it more manageable for staff. We will not just maintain space for the hell of it."
At Garforth, the covered planteria is 4,000sq ft and the outdoor area is 8,000sq ft, while the shop is 26,000sq ft. Many Hillier centres have different proportions, with larger planterias and smaller shops. Francis said that can suit its reputation as a grower. He added that Hillier is now the largest customer of its own nursery, with 25 per cent of stock going to its garden centres.
Nursery stock, bedding and restaurants still make up more than 50 per cent of sales in the season, he pointed out. Overall sales are up nine per cent in the financial year to September 2016 and 17 per cent up afterwards.
Only one Hillier, Eastbourne, offers a "shopping village" concept and a 20,000sq ft five-concession extension is to be built there, due for completion in May 2017.
Francis added: "This year has been a very good year. The financial year to the end of September ended nine per cent up and we're 13 per cent up since then. This was a good result after the wettest winter ever in 2015-16 and the coldest spring until the end of April. But we had the best ever May by a long way and that carried on into June, July and August."
He said Hillier's RHS Chelsea Flower Show stand will be in the same place as 2015, in the pavilion, but not next to the monument. Sarah Eberle is designing and Caitlin Mclaughlin, the RHS young designer of the year, is also involved.
The second annual Hillier Garden Centre Awards, recently held in Southampton, saw planteria of the year won by Newbury (up 24 per cent) and plant category supplier of the year awarded to Meon Valley Nurseries.
Retail consultant Neville Stein said: "It is a good idea to reduce the size as long as stock turn is improved. In other words, the skill is to sell more from a smaller site. By having a reduced space for plants it means that the space has to be managed more effectively. This will, of course, involve more work if one is to increase the stock turn."
He added: "There will be more deliveries being received, more paperwork to process and, of course, more merchandising. But the benefits of an increased stock turn, fresher plants, a frequently changing range etc all outweigh the disadvantages. If one can sell more from a reduced space then it does mean that the extra space can be used for new product categories, which in turn will help to grow sales."
Mdj2 associates director Andy Newman said: "It is noticeable that external planterias seem to be getting smaller, especially in new-build and redeveloped centres. That said, many leading operators have been introducing more versatile buildings that can create a more versatile balance between indoor and outdoor space dependent on weather conditions - such as Bents 'open skies' building and Blue Diamond's atrium at Redfields.
"As we have seen over recent years, it's not necessarily the size of a planteria that matters. It's how well it is designed, fixturised and merchandised that matters. You don't need masses of space, instead healthy, fresh-looking plants really well merchandised are much more likely to catch a customers eye - and purse or wallet."