Beardshaw said the industry's failure to shake off its image problem combined with ongoing skills shortages were hampering recruitment into the sector.
"Having spent years in education, I still find it increasingly frustrating that modern-day courses in some cases don't actually relate to what goes on in the real world," said Beardshaw.
"I still meet people who have no concept of the complexity of hard landscaping and planting design. Colleges are faced with a real challenge to provide sufficient knowledge for students in the short time they're at college."
Beardshaw launched his own mentoring scholarship last year. Budding horticulturists compete for the chance to spend a year working alongside the RHS medal-winning designer.
Last year 15 people had applied but this year 80 applications are in and Beardshaw expects the figure to rise to 150.
Beardshaw's first scholar, Lindsay Anglin, from Bristol, won an RHS gold medal for her Bradstone Bacchus Garden at the Malvern Autumn Show last weekend. She set up her design practice Green & Stone after gaining a garden design diploma from Pickard School of Garden Design and will build an urban garden at the RHS Chelsea Flower Show in May, under Beardshaw's supervision.
Anglin said: "It's the launch of my career as a garden designer."
Beardshaw will reveal the second winner of his mentoring scheme in May.
- Horticulture is set to be given a boost when gardening returns to prime-time BBC One in November for the first time since Ground Force was axed. Beardshaw will team up with Nick Knowles to present Wild About Your Garden, a six-part series that transforms back gardens from no-go areas into wildlife havens.