Alton Garden Centre director Andy Bunker said strong sales "bodes well for autumn" with pack bedding sales double normal levels in the past two weeks.
He added it was the best ever bank holidy on plants, with gardening aquatics and BBQ also doing well: "There’s a lot of people still gardening and we’re very, very busy. It’s been one of the best bank holidays we’ve had and it’s been a good year after last year."
He said August was 10 per cent up compared to August 2015, and year to date is 6.5 per cent up. The planteria is eight per cent up in August, and four per cet up year to date.
Mappleborough Green Garden Centre in Redditch has seen "about a three-fold increase for the centre plus steady growth in the coffee shop," in the past few weeks after expanding following redevelopment.
Hillier director Chris Francis said August garden centre sales had been "very good", "with nursery stock sales being particularly strong".
Perrywood’s Hannah Powell said: "The first three weeks of August garden centre were up seven per cent compared to last year. This is a similar increase to previous months of 2016 here at Perrywood. We’ve kept well stocked with plants through the summer and as a result sales have been good. Good sales of discounted furniture. Coffee shop similar to last year."
Hayes Garden World e-commerce manager Lyndan Orvis said: "It's certainly been one of those years where the weather has not played ball as often as we would have liked. But some nice weather of late has meant that the season has run a little longer so should end up been a good season."
CBI figures showed 35 per cent of retailers said that sales volumes were up in August on a year ago, while 26 per cent said they were down, giving a balance of +9 per cent, beating gloomy post-Brexit forecast.
UK garden pots supplier Woodlodge director Michael Wooldridge said on the August Bank Holiday garden retail sales: "It is encouraging to see strong garden centre trading figures across August’s Bank Holiday weekend, and it’s unlikely to stop there. With predictions for a mild September, customers will make the most of the weather and spend as much time in the garden as possible. This means strong sales are likely to last well into autumn and early winter. Garden centres and retailers must ensure they meet customer demand by keeping shelves well stocked – this will not only to maximise sales but continue to attract and inspire visitors.
"Although the wet spring made for a slow start to 2016, we’ve had a very successful season at Woodlodge and are glad to see sales of pots and planters maintaining momentum at this time of year."
At Waitrose, total divisional sales (excluding fuel) were up by 4.7 per cent, compared with the same week last year.
Food to go sales performed strongly, up 10.5 per cent. Finance director Loraine Woodhouse said: "The summer sunshine and the sporting spectacles in Rio have been inspiring people to head outdoors, with outdoor living up 24 per cent and sun creams up 37 per cent. Fresh produce continued to show strong sales, up 9.6 per cent, as customers picked up British seasonal fruit and veg such as sweetcorn (+six per cent) and cherries (+36 per cent).
John Lewis sales were +1.3 per cent on the year at £72.9m, with Outdoor Living products finishing the week at +64.6 per cent.
With a week to go, sales month to date are 40 per cent up on 2015 and have been driven by strong demand for its garden furniture, BBQ and solar lighting ranges.
Year to date gardening is tracking 16 per cent up on 2015 numbers, with horticulture sales nearly double at 93 per cent up.
Gerrard Smith, JTF senior buyer, said: "We are really pleased with our results so far, especially considering the growth is on the back of our record ever sales year in 2015. We are supported by a strong supply base who have performed well for us in terms of supporting with innovation & maintaining availability throughout the season."
On the High Street, the number of people out shopping in the UK on Saturday and Sunday fell by 4.1 per cent compared with last year's August bank holiday, retail researchers say.
Analysis firm Springboard had predicted a 6.5 per cent increase in footfall at shopping centres, retail parks and high streets.
Springboard's Diane Wehrle said bank holidays were becoming more focused on leisure activities such as eating out, and that there had been a shift from daytime shopping to evening trips, helped by food outlets staying open.