Businesses are being forced to recruit from overseas amid an "alarming" shortage of skilled workers in the UK, according to a new report spearheaded by the Royal Horticultural Society (RHS).
In a foreword to the report, Titchmarsh warns that gardening is undervalued by the Government, the public and young people, and suggests that more should be done to encourage the nation's teenagers to spend more time working with "plant cells rather than cell phones".
Previous research has shown that many youngsters believe that horticultural careers are unskilled jobs for those who have failed academically, said the TV gardener and presenter.
The study, which surveyed around 200 horticultural businesses, found that more than 70% are struggling to find the skilled workers they need, while two thirds (67%) suggested that those entering the profession are inadequately prepared for work. Around a fifth (19%) of the businesses questioned said that they are being forced to recruit workers from overseas.
The report warns: "The seriousness of the situation must not be ignored. The main cause of the crisis is the belief that horticulture is simply a hobby, and not a serious or rewarding career for talented people; this despite the fact that most in the industry are highly skilled and have undergone years of professional training. This misconception is not helped when politicians regularly refer to gardening as an unskilled, manual job.
"One consequence is that teachers and career advisers seldom recommend horticulture to their students and the demand for further and higher education courses is in decline."
In his foreword, Titchmarsh said that gardeners have "the best jobs in the world". But he adds: "And yet our role is undervalued by Government, by the population and by young people in particular - in every instance because they just do not understand the breadth of what we do and its importance in terms of the wellbeing of the planet and its population."
RHS director general Sue Biggs said: "We are unanimous in the belief that there must now be urgent action to save British horticulture and it must happen now. Our report calls on the Government, employers and those in the education system to take action to safeguard the critical role that horticulture plays in Britain today."