While plant life is the centerpiece at the Minnesota Landscape Arboretum, animals get to take a turn in the spotlight for one day only, when the facility’s Three-Mile Drive becomes a walking route for the family dog.

Canine companions are invited to the arboretum’s All About Dogs Day, Saturday April 21, from 9 a.m. to noon. The event features a bazaar of pet-related vendors, costumes and prizes. But the main attraction is the ability to walk the arboretum’s central loop with a furry friend by your side.

It’s both a departure and a throwback for the University of Minnesota’s horticultural research center, which once allowed dogs — and even horses — on its 1,200 acres. The arboretum went people-only years ago.

“Let’s face it, dogs can do some damage and not everyone cleans up after their dogs in the right ways,” said Susie Eaton Hopper, arboretum spokeswoman. “As the arboretum grew and we had more formal gardens and more visitors, [allowing pets] just didn’t seem like a good idea.”

But that way of thinking is starting to change.

All About Dogs Day, launched eight years ago, has become a popular annual event. Last year, 400 canine visitors attended. The cost is $20 per dog ($15 for members), including two adult companions. The arboretum is thinking of adding a second dog day date in the fall.

The arboretum does have trails where dogs are welcome all season long.

In 2016, it introduced Dog Commons, a swath of trails on 65 acres separated from the rest of the facility’s gardens and woods. The commons, which is typically open from April to November, includes interpretive messaging with occasional dog-centric activities. Arboretum members can add up to two dogs onto their membership ($50 annually for basic members, free for donor-level and above), and can walk those trails with their dogs — on leash at all times due to the other wildlife in the area.

Jean Larson, head of the arboretum’s Nature-Based Therapeutic Services program, was the mastermind behind Dog Commons, which she pitched as part of a larger plan to make the arboretum more animal-friendly.

“I kept on saying, ‘People have dogs. You’ll be capitalizing on a whole new population,’ ” said Larson, who has been with the arboretum for 26 years.

When Peter C. Moe became director in 2016, Larson noticed “an evolution” for making the arboretum more accommodating to pet owners. In fact, Moe will be leading one of the All About Dogs Day guided walks, along with his own dog.

The Dog Commons trails were the first phase of Larson’s plan. The next two phases will depend on donations. One would be to create a demonstration garden of a dog-appropriate backyard, including urine-tolerant grass. The other would be to install a methane digester that turns dog droppings into energy.

“That would be my dream,” Larson said.

There’s biological backing for the idea of integrating family pets into people’s experiences of this plant sanctuary.

“Being in nature is calming and soothing. It gives us a grounding and a sense of security,” Larson said. “And being with your dog and having that connection out in beautiful nature — hearing the birds, having the sun, feeling the breeze — that all contributes to freedom from stress.”

“Nature,” she said, “reboots our brains.”