Last month, the Gazette reported on a fire that gutted the information centre at the park, off The Parkway, in Hayes.
The blaze seriously damaged an 18th century statue of a woman and Cupid, which used to stand by the River Crane.
Bob Barton, secretary of Cranford Park Friends, said the figure was believed by some people to have inspired the legend of the Grey Lady, who is rumoured to haunt the 144-acre park.
“This is a major blow to the Cranford Park Friends group at a time we are attracting increasing numbers of volunteers, bringing the community together and working closely with Hillingdon council and Macmillan Cancer Support,” Mr Barton said.
It’s a very relaxing place and patients enjoy coming here once a month to work and meet with other people”
But the fire has not stopped more than 20 volunteers, including patients from Hillingdon Hospital, continuing to look after the garden.
The walled garden is one of the few reminders of the Earls of Berkeley, whose estate consisted of the park and surrounding land, now managed by Hillingdon Council.
Macmillan Cancer Support, which opened an office in the hospital in Pield Heath Road earlier this year, has been working with the friends group to organise the volunteer work.
Lorraine Barton, a Macmillan cancer specialist and one of the founding members of the park’s friends group, said: “It’s a very relaxing place and patients enjoy coming here once a month to work and meet with other people.
“It gets people out of their homes and active, which is important when you are recovering.”
The walled garden’s features include a small vegetable and wildflower plot, a natural well and its own grapevine, which this year helped produce 20 bottles of Cranford wine.
The Berkeleys were one of the country’s richest families but the family home was sold in 1918 and later demolished.
As well as the walled garden, a few remnants of its opulent past remain, including stables and a huge tiled cellar hidden underground, which the Friends hope they will be able to restore in the future with the help of the council and a Heritage Lottery Fund grant.
Cranford Park Friends are on the lookout for volunteers. For more information go to www. cranfordparkfriends.org.