Some garden centres have reported shortages in some product areas this spring, which has seen fluctuating supply and demand and lacks the former £90m turnover Solus. Scotts bought the company out of administration in July 2014 after a prolonged process, which meant the new Scotts Solus was not fully prepared for the 2015 season.
Scotts bought Solus brands including tools and birdcare under the Yeoman, Joseph Bentley, ChapelWood, Botanico, Garden Nation and Bermuda names.
Gardman is now the largest supplier in the market and Harper said air freighting a range of lighter-weight garden product has to be done this spring.
He said Gardman picked up a lot of business and increased stock holding by £2m and turnover by 20 per cent in the first quarter, but "peaks and troughs" in the market this spring have led to distribution issues across the industry.
Harper, who is also Growing Media Association chairperson, added that at least two compost companies were having some supply issues.
Harper left Bord na Mona UK at the end of January 2015 to take up a post as sales director at Gardman.