Do visitors destroy gardens?

John Sales joined the National Trust in 1971 and served as the chief gardens adviser for 25 years before retiring in 1998. He has seen garden visiting change beyond recognition. Gardens are now by far the most popular items in the National Trust portfolio – more than half the people who join the National Trust do so at a garden.

But this surge in popularity, while welcome, brings its own problems. "It's fair to say that when the Trust acquired its gardens, it never anticipated this level of garden visiting," says Sales. With many more visitors coming from ever farther afield, space has to be found for car parks, refreshments and lavatories. "And the million-dollar question is how the needs of visitors can be balanced against garden conservation, how to make them welcome without destroying the very thing they have come to see."

Choices always have to be made – many feet will wear out grassy paths, but replace them with gravel or Tarmac, and you radically alter a garden's character. Visitor safety is paramount, but who wants to see every pond fenced? People need to sit, but too many benches will make the garden look like a public park: "Little decisions can gradually create a creeping municipalisation that undermines the atmosphere of the garden."

The role of staff and volunteers is also a delicate one. On the one hand, gardeners are delighted when visitors show an interest in their work. On the other, most National Trust gardens require a very high standard of upkeep, and there are rarely enough hands for the task. If a gardener is constantly stopping to chat, some vital task may not be performed that day. Volunteers, while invaluable, don't generally have the skills of a professional.

In some gardens at peak times, Sales says, the press of visitors is such that, "It's difficult to see what pleasure can be derived from it, let alone any understanding of the garden and how it was made, who made it, and why it is different from any other garden.

"The only way around it is either to price people out, which is unacceptable to the Trust, or to introduce timed tickets, which the public hate."