Monty Don said in a recent talk at Hever Castle that Jenkins had told him that "gardens are now a much bigger visitor attraction for the National Trust than houses".
Jenkins said: "If you look at our visitor numbers for last year many of the places in the top 10 were houses with gardens, or gardens and landscapes. Our 200 gardens are a big attraction to both members and non-members and really help us to deliver something special for both horticultural enthusiasts and those who enjoy being outdoors and experiencing the visual impact of our gardens, which are looked after and cared for by our talented gardening teams."
Hill Top, the home of Peter Rabbit author Beatrix Potter, in South Lakeland, has seen visitor numbers helped by a CBeebies Peter Rabbit series, with 3,500 visitors last week.
A representative said: "Last year was quieter because of the Olympics and weather but the group market has picked up this June."