The NGS Traineeship programme will identify four trainees a year to work at one of the four RHS gardens - Wisley in Surrey, Harlow Carr in North Yorkshire, Hyde Hall in Essex and Rosemoor in Devon - for 12-months.
During the programme the trainees, who must have a Level 2 Diploma in Horticulture-level qualification and at least six months of practical horticultural experience in a professional environment to be accepted, will get on-the-job training in a range of disciplines, including ornamental cultivation, glasshouse growing, fruit growing and rock gardening.
The four NGS trainees will also work with private gardeners in the run up to the NGS Open Gardens programme, where gardens across the garden are opened up to the public for charity during the National Gardens Weekend in June.
RHS executive vice president Jim Gardiner said: "The creation of these NGS Traineeships is yet another example of horticultural organisations coming together to provide more people will the skills they will need to thrive in what I consider to be the most enjoyable and stimulating profession in the world. The partnership also underscores our commitment, expressed in the Horticulture Matters report, to help more people forge careers in horticulture.
"The RHS already enjoys a hugely positive relationship with the NGS, but the creation of the traineeships really reinforces our joint aim to ensure that everyone has access to the wonders of gardens, gardening and horticulture."
National Gardens Scheme chairman Penny Snell said: "We see this initiative as the basis for an exciting new partnership between the RHS and NGS and emphasises our commitment to training young gardeners for a career in horticulture."
The first four NGS trainees will begin their training in September.