Alan was speaking ahead of a special event to celebrate 175 years of the charity Perennial, which helps horticulturists in times of crisis.
The ITV Love Your Garden host, who is president of Perennial, said: “My chosen career and love of gardens and gardening have given me more opportunity than most to appreciate the dedication, determination and sheer hardiness of those who work in horticulture.
“From grounds staff who meticulously prepare turf for sport, to parks staff who lovingly tend borders and lawns; gardeners, landscapers, designers and nurserymen share a passion for plants and green spaces.”
Perennial will try to raise an extra £175,000 this year to help gardeners struggling with disability, debt or illness.
Alan added: “The work of Perennial is needed more than ever. Horticulture is a profession not for those who covet wealth, but for those who know watching a seed grow has importance beyond the personal pleasure it provides. Simply, it is something on which we all depend.”