"It's a totally different atmosphere at night," Joanne Jackson said.
By night, the garden transforms into a space for raccoons, coyotes, bats, deer, rabbits, owls and frogs, instead of a place for people.
"There's no large crowd bustling about, there's absolute silence, except for the sounds you hear in the garden," Jim Jackson said. "The darkness makes it a world of its own. It takes on a whole different aura. When darkness falls, the garden is taken over by the garden itself. It's a very interesting place to be with the sounds and animals. It's solitude but not loneliness."
Garden spiders are the one animal that bring more interest and conversation among participants, Jim Jackson said.
"It's probably because of the fear," he said. "Almost everybody is in awe, even if they have an aversion to spiders, because when you're there in the daytime, you would never think there's a spider there."
As the weather gets warmer, the spiders get larger, he added.
The couple's adventures include running into packs of raccoons, finding 50 pairs of eyes staring. Coyotes have also followed the group during exploration.
"The night walks give a chance to explore Descanso with people, Joanne and I, who are interested in exploring it a little further," Jim Jackson said.
As the months get warmer, the bats will come out in greater abundance in search of insects, a sight that Jim Jackson recommends to visitors for his next walk.
"We enjoy sharing Descanso with people," he said. "It's a way to get away from the television. It's a very easy way to spend an enjoyable evening."
David Brown, executive director of the gardens, became familiar with the Jacksons and the tour after he began his job in summer 2005.
"In my first few weeks as executive director, I took the night walk with Jim and was both inspired and entertained by Jim's far-reaching knowledge of the gardens' colorful history and the various critters that take over that beautiful place when all the people leave and the sun goes down," Brown said.