We gleefully pillory both venerable "old ladies" from time to time. But the loss of either would leave an unfillable gaping hole in British society.
The benefit gained by 200 years of effort and enthusiasm from the RHS is writ large in the science of horticulture and the arts of gardening. Change is pushing the RHS towards more outward-looking and collaborative attitudes. Not least, it seeks greater partnerships with the associated societies - restoring their recent neglect.
Similarly, qualifications give the RHS golden opportunities. It owns a complete slate of qualifications from the certificate that attests to competence in basic skills to the flagship Master of Horticulture. M.Hort holders are well versed in science and are capable business practitioners exploiting knowledge in pursuit of profit. That may be social, environmental or financial profit.
Gaining this qualification is by self-motivated, part-time learning guided by approved mentors. This ideally suits candidates with established employment wishing for career advancement. Qualifications provision has emerged relatively unscathed, being a small group of staff with a tightly organised operation. By their determination, the RHS is headed towards becoming a formally recognised horticultural examinations body.
Bringing children towards an appreciation of plants and gardens is a long cherished RHS ambition. Its programme of welcoming children into the four gardens is being boosted. The aim is achieving more than "a botanic appreciation of plants".
Its network of regional advisers offers practical gardening education. Learning centres are being established with each garden around the country and these will operate in collaboration with other local gardening interests. Regional activity is one of the RHS's major strategic successes and the recent donation that is funding Rosemoor's new learning centre typifies that success.
Professor Geoffrey Dixon is managing director of GreenGene International.