Her own garden is divided into three. A scruffy wildlife area with willow, birch and plum trees and a pond full of frogs. An informal garden with densely planted beds, apple trees and a well surrounded by rhododendrons. In the small vegetable garden she grows runner beans, potatoes, chard and carrots, and plants out cuttings and seedlings for the following year.

Susan says: 'I've always been self-taught, but I decided to take things a step further by enrolling for a three-year diploma course with the Horticultural Correspondence College. It's quite scientific, and mainly theory rather than practice, studying things like the chemistry and biology of plants and how soil systems work. I've always used compost and manure, but now I know why it works.

The Royal Horticultural College diploma in horticulture is a challenging qualification, which is the equivalent of two A levels. It's divided into 12 bite-sized chunks, which means that you can take it at your own pace and do more in the winter, when there's less to do in the garden. If I pass the examination in 2002, I might go on to study a degree course in garden history or garden archaeology. Home study fits into our way of life here. There's a lot of physical, hard work in gardening, but life here is so peaceful. I wouldn't want to change a thing.'