By day, visitors flock to the University of Minnesota Landscape Arboretum in Chanhassen, attracted by its showcase gardens, tree collections, prairies and wetlands.

By night, the plants lure a different audience: deer. They chow down on the preserve’s trillium, arborvitae, roses, apple saplings and hundreds of other delicacies.

Now the arboretum has launched a counteroffensive: It’s building a $260,000 galvanized fence along nearly 3 miles of its southern boundary to keep the deer out.

“We had the worst deer damage in 25 years this last winter,” said Peter Moe, director of operations at the arboretum, which attracts hundreds of thousands of human visitors annually. Deer chomped every green shoot and killed every yew and arborvitae along the arboretum’s shrub walk, he said. They feasted on dwarf conifers, azalea buds, hostas and dozens of other plants, including areas near the arboretum’s main parking lot and visitor center.

The deer are jeopardizing research projects, the beauty of the grounds and natural reproduction of plants and trees at the preserve, Moe said. “We just can’t tolerate as many deer as we have on the property.”

For years, the arboretum has fenced its research orchards and other key growing areas to keep deer out, but now almost all of its 1,127 acres will be fenced, except for a portion along Hwy. 5 that includes its main entrance.

But human neighbors across the street from the new fence don’t like its shiny steel poles and braces, and doubt that the structure will be effective.

“It’s just so unsightly,” said Kara Thom, one of about a dozen homeowners along 82nd Street where the fence runs.

“A fence is so unbecoming for what we know and love about the arboretum,” she said. “To me, it doesn’t represent what they stand for at all.”

A crew neared completion of the project last week. Moe said it’s the same style of fence used widely in Minnesota to keep deer out of orchards, vineyards and nurseries.

It’s made of galvanized high-tensile steel, with 8 feet of woven wire mesh and two smooth wires strung across the top, making it 10 feet tall. The mesh is mostly 6-inch-by-12-inch squares with closer spacing at the bottom. It’s nearly invisible from a distance.

It is not buried, Moe said, so that foxes, raccoons, skunks, opossums and other small wildlife can squeeze through or under it.

Ross Johnson, another neighbor, said that the segment of fence across from his home looks like a baseball backstop, with shiny poles and braces as the fence makes a turn to the north. “It’s entirely within their right to do it, but it contradicts much of what they publish about environmental preservation,” he said.

Guarding the garden

Moe said he understands the neighbors’ concerns, but the arboretum had run out of options. In addition to temporary fencing in certain areas, officials have allowed bow hunting each fall to reduce the deer population, he said. However, an aerial survey after last year’s hunt showed that there were still 44 deer on arboretum property in early January.

While the grounds can tolerate some damage, Moe said the number of deer in recent years is far too many. “We are not a nature center,” he said. “An arboretum or any public garden is really a different type of institution.”

The arboretum keeps track of where many of its plants came from, when they arrived, where they’re located, and how they’ve grown for the past five, 10 or 50 years, he said. “What we have is plant collections, and they’re very valuable,” Moe said.

The arboretum has added other valuables, including a new outdoor sculpture garden with nearly two dozen world-class sculptures that are in the process of being installed.

Moe said deer, not security, was the driving factor in building the fence. A private donation is paying for the project.

“Security is part of the issue,” he said. “We’ve had equipment stolen and some car break-ins. We don’t make a big issue out of it, but we’ve had some of the same crimes that happen at other public facilities.”

An offensive fence?

Thom said she doesn’t think the fence will be effective, because deer can cross into the arboretum from the north, along Hwy. 5, which will not be fenced. When she heard about the fence planned along her street, Thom said she and others asked the arboretum to install wooden posts instead of galvanized steel, to lessen the visual impact. They also wanted arboretum managers to erect the fence farther from the road and to plant shrubs or spruce trees to hide the fence.

Because they did neither, Johnson said neighbors are frustrated.

“I’m sure it will soften over time, but right now it’s pretty raw,” he said. “Everybody’s a little bit upset, and one of my neighbors says it’s like living across from a prison.”

Wildlife is also confused, Johnson said. Wild turkeys caught on the arboretum side of the new fence just keep walking into it, he said, because they can’t get out.

Moe said steel poles were installed instead of wood because they’ll last much longer, and the arboretum wants to be a good neighbor.

“We’ve told the neighbors that we’ll do some landscaping,” he said. “We just haven’t said exactly what.”

But Moe is firm that after years of struggling with deer damage, a fence is needed to ratchet up protection.

“We’ll always be a terrific place for almost every species of wildlife to live,” he said. “But the ones that feed on plants — they have to be excluded.”