For over 15 years, the tall, evergreen pine trees of The Old Rugged Cross Memorial Garden have been an essential part of the charm of the small Pokagon Township park that caretakers have called a “church without walls.”

A fungal pathogen has taken root within a sizable portion of these trees, though, which threatens to scar the garden’s landscape.

Earlier this year, members of Pokagon United Methodist Church responsible for upkeep of the green space discovered that Rhizosphaera needle cast, a tree disease caused by the fungus Rhizosphaera kalkhoffi, had infected several of the blue spruce trees within the park. The disease primarily affects younger needles contained on lower branches, causing the needles to become discolored and eventually fall off, which creates large bare spots on the otherwise healthy tree.

The spruce trees had been suffering from issues since last year, said Bev Bennett, a volunteer who manages the garden.

“It’s been happening for quite a while, but we didn’t know what the cause was until the spring,” Bennett said.

Chris Thomas, an arborist with MAAC Property Services in Niles, made the diagnosis. Thomas has been helping the group combat the disease, which will eventually kill the entire plant if not treated.

The fungus has already claimed the life of one of the garden’s trees. The remaining infected plants will be trimmed 5 to 6 feet up from the ground, in hopes that the increased open space will improve air circulation and eliminate the damp conditions the fungus needs to thrive, Bennett said.

This work should begin later this summer, though only time will tell how effective the treatment will be at halting the disease or on the impact it will have on the aesthetics of the garden.

“We’re just kind in limbo about what will happen until we see how the garden looks when the trees are trimmed,” Bennett said

The blue spruces have been around since the garden was established in 1998 by members of the Methodist Church, which is located across the street.

“We have lots of different trees, but the blue spruces are so pretty,” Bennett said. “They’re kind of the primary tree we have, since they circle the hill at the edge of the property.”

This is the first time that the nine-member committee responsible for overseeing the property has had to deal with a potentially deadly plant disease. The church had originally bought the foreclosed property 16 years ago, transforming the lot into a spiritual garden, with religious statues and iconography joining with the small stream and abundant plant life. The space is often used for small church services and weddings, Bennett said.

“The garden is mostly used by people who want to stop by and enjoy the peace and quiet, to meditate and pray,” she said. “People from all over the world have come to enjoy it.”

The committee is seeking donations to help cover the cost of treatment and for other landscaping concerns with the garden. People can contribute by sending money to the church, which is located at 31393 Kansas St. in Dowagiac.