Woodlands Hall and the Dairy House at Glazeley, near Bridgnorth, will be open from 2pm to 5pm on Saturday, June 12.
The event will be raising money for both Chelmarsh and Glazeley Churches, as well as Kidney Research UK.
The garden is owned by Roger Gabb, and his son Caspar, a successful landscape and garden designer, said the event is also being held in memory of his mother, Annie Gabb, who died aged 77 in January.
The family have normally opened the garden up to the public once a year to raise money for good causes.
Caspar, a previous gold medal winner at Chelsea Flower Show, who has also scooped top prize at Shrewsbury Flower show, will be on hand to share his expertise with visitors.
Kidney Research is a charity particularly close to the family's hearts with Caspar having received a kidney from his father Roger, who was 78 at the time, four years ago.
Caspar was born with a hereditary condition called polycystic kidneys, a genetic disorder which causes cysts to grow in the kidneys.
He said they would be looking forward to welcoming visitors, adding: "The gardens have been developed over 40 years. There are many different gardens, so there is something for everybody. There’s a kitchen garden, a courtyard garden and more. It’s a beautiful location.
“They are very special gardens so I hope the weather holds out and that lots of people come along, enjoy the gardens and donate.”
The day will also include an unusual plants stall, a children's trail and a woodland walk, while people will be able to buy tea and cakes.
Entry costs £5 for adults and £3 for children five and over. Visitors are also asked not to take dogs.