The event attracts 12,000 people over nine days. He said filming and weddings boost income during the year, but "we have never had the visitor numbers we would like".
"We'd like to see more visitors and we'd like those people to enjoy the features of which we're most proud. That's where the Enchanted Woodland comes in."
The illuminated walk around the arboretum and 18th century lake is "doing well" after "a few difficult years of getting established".
Martyn said the event focuses on the arboretum and is a "huge boost to the morale of gardening staff at a depressing time of year".