Most horticulturists are struggling to recruit British workers with the skills they need, according to a new report.
The Royal Horticultural Society said an estimated 11,000 jobs will be created in the industry over the next few years, but there are concerns that not all the positions will be filled.
Firms have told the RHS they are having problems finding young, British applicants for jobs including nursery technicians, plant growers, spray operators, pruners and environmental control experts.
Sue Biggs, director-general of the RHS, said: "Until now, concerns that Britain's green skills gap is being increasingly filled by skilled workers from abroad have been largely anecdotal.
"This investigation provides evidence direct from the experiences of the growers themselves.
"We must work hard to now to attract more young people into horticultural careers."