The year to the end of June was 11 per cent down on last year with May sales eight per cent down and June sales three per cent up.
The HTA says latest GDP figures, which show that between April and June the UK economy shrank by 0.7 per cent, reflect what the garden industry has been seeing in recent months.
HTA marketing director Andrew Maxted said:
"The latest HTA Market Update reflects the reality of exceptionally tough trading conditions this spring. Growers, garden centres and landscapers alike have seen the wettest and coldest April-June period in memory combining with low consumer confidence and squeezed household budgets.
"The core garden market is however resilient and still shows every sign of wanting to take advantage of the recent improvement in the weather and this latest report focuses on opportunities within the older and keener gardening consumer segments.
"At the same time the narrowing gap between inflation and earnings should help attract younger gardeners back into the market and the HTA’s new Plan it, Plant it autumn PR campaign is very much designed to build on this."