On a crisp, bright morning, Bob Newell, 77, from Wokingham, Berkshire, plucks a sprig of rosemary from a pot, smiles, and says it reminds him of roast lamb. Memories are precious to the retired metallurgist; he had Alzheimer's diagnosed ten years ago.

He is walking through a kitchen garden on a country estate just outside Reading, but this is a garden with a difference, one that is designed to evoke fond memories. It is decorated with wind chimes, water features and old-fashioned washing lines.

The garden is part of a network of plots and farmland at the charity Thrive, an organisation that promotes therapeutic gardening at its headquarters, set in 130 acres. It aims to improve wellbeing and independence in dementia sufferers by engaging them in horticulture.

Thrive takes about ten people a day. They do everything from planting seedlings in the glasshouse, to working on their individual plots of ground, in which they can grow whatever they like, from hollyhock and sweet peas to lavender and potatoes.

Newell started attending the Thrive project five years ago after a family friend recommended it, knowing that he was a keen gardener.

Val, Newell's wife, says they couldn't have imagined how positive the experience would be: “We've never looked back. It has done wonders and came just at the right time.” Alzheimer's is a cruel disease, slowly eating away at personalities and stealing independence. Val believes that the gardening project has helped Bob to hold on to his sense of self.

“When someone loses so much, finding something that they can do, and enjoy, means an awful lot,” she says.

Nicola Carruthers, the chief executive of Thrive, says that the simple act of planting, nurturing and growing a plant can be surprisingly empowering to someone who is struggling with dementia. “It's all about ownership. It's so you can say that's mine; that's what I worked on. The disease causes a massive sense of isolation. As people decline, they lose themselves. They may have previously been high-fliers, but after the diagnosis people start talking to the person next to them, not to them directly,” Carruthers says.

She adds that the project helps to ease the pressure on carers, providing respite while their loved ones are at the garden. It can also help them to see their family member as a person again.

“For a lot of people, their family stop seeing them as a person and only see them as the illness. A lady who brought her mother along said she never expected much from this project, but has now started gardening at home with her mother and the rest of the family. They are starting to see her as mum and granny again,” she says.

With the money gained from the Times appeal, Thrive hopes to make a series of booklets and DVDs for people with dementia and their families. These will provide tips and techniques for gardening at home, with suggestions and advice on which plants to grow.

“It doesn't have to be a grand project - something as small as a tub or a windowbox is enough. It's about having some fun and lifting the burden of dementia, even if it's for an hour only. Imagine how good that would feel,” says Carruthers.

Val Newell echoes this sentiment. “If you have a loved one with dementia, find an activity that they can enjoy and get satisfaction from. It's so important when so much is taken away from them.”

And although Newell is in the later stages of the disease, glimmers of his personality and humour still shine through. After the Times photographer thanks him for his time, Newell says as he walks back to the garden: “This one is free, but I'll be charging next time.”

Thrive is one of the charities that will benefit from this year's Times charity appeal.

Donate to the Times Christmas appeal online timesonline.co.uk/timesappeal