"Gardening is among the lowest-paid professions and it is shocking we allow that to happen," said Beardshaw."The result is that we don't draw people into horticulture and even if we do, it is often difficult to sustain a career."
Beardshaw gave a lecture entitled Gardening Through the Year at the Camelia Botnar Foundation's Homes & Gardens centre in Cowfold, West Sussex, on 14 March.
The Foundation trains apprentices from disadvantaged backgrounds in skills including horticulture, pottery, catering and grounds maintenance.
"The UK is considered to be a leader in terms of the quality of its gardens and parks, and it strikes me as peculiar that we are in a situation where it's very difficult for young people to sustain a job in horticulture," added Beardshaw.
"The people who manage large gardens and estates do fantastic jobs and in some quarters they are not well valued. If these gardens were works of art it would be a different story."
Beardshaw congratulated the Camelia Botnar Foundation for the work it was doing to help young people gain the skills for a successful career in the sector.
Camelia Botnar's trainee development manager Emma Wild said: "All the young people who work for us in the garden centre are being fully trained as horticulturists in order to enter the industry."
- Visit www.cameliabotnar.com
"We work the apprentices extremely hard and they sometimes overcome a lot of difficulties to come to work every day so we are full of admiration for them," she said.