Canoe Creek State Park environmental education specialist Heidi Mullendore shows a Russian olive shrub near the park’s Terry Wentz Education Center. Mirror photo by Patrick Waksmunski

Those heading out to Canoe Creek State Park over the coming weeks might notice an abundance of shrubbery that appears to be taking over some of the park’s open spaces.

Russian olive and autumn olive — the two beautiful yet extremely invasive shrubs — are not only found at the park, but across Blair County’s landscape. Canoe Creek employees are working to control the spread, and property owners are urged to do the same.

Russian olive and autumn olive can get quite large and “ruin” the view, said Heidi Mullendore, Canoe Creek’s environmental education specialist. Instead of seeing a field with flowers and birds, there can be a mass of shrubs “everywhere you look.”

Originating in Asia, these plants were imported for aesthetics and their strong survival skills. Plants feed on three main kinds of nutrients: potassium, nitrogen and phosphorus. The fact that these shrubs are able to fix their own nitrogen means they are able to thrive on poor, disturbed soils — such as lands near coal mines or roads. They are drought-tolerant, too.

“By the time we noticed, it’s taking over the native landscape, it’s too late,” said Lisa Haas, environmental educator with the Blair County Conservation District.

The shrubs are thriving in state parks and native lands. They are green almost year-round and produce a lot of berries. Their seeds get easily carried by birds and spread even wider.

Mullendore said the plants’ leaves come out earlier than native plants, therefore they choke out native plants that are trying to grow.

“Invasive species like that can form a monoculture; instead of the diversity of native plants that would be there, you would just have Russian olive and autumn olive,” Mullendore said.

The plants’ seeds are also not very nutritious for birds. They are mostly made out of carbohydrates and are low in fats. As an explanation of the nutritional value, Hass said birds eating these seeds are eating cake all day instead of a balanced diet.

However, removing these plants has been a challenge to the state park. Mullendore said the seeds could stay in the ground for decades.

“As soon as you cut down the shrub, the soil is exposed to the sunlight, and the seed gets exposed to sunlight and starts to grow,” Mullendore said. “So you can remove the shrubs in one year … within three years that field will fill right up again with full-grown shrubs.”

“State parks don’t have an unending supply of volunteer labor or money to face this problem to any successful degree. We are always playing catch-up,” Mullendore said.

Joe Basil, Canoe Creek State Park manager, said the park is proactive in keeping autumn olives out by mechanically removing them with a skid steer and chemical treatment. The park also plans to do a prescribed burn this fall.

If people ever discover these shrubs in their yard, Haas advises treating them as soon as possible.

“When it’s very small, and you get it in time, you can hand pull it,” Haas said. “You have to be careful and take out all the roots. Even if you just left part of the roots in the ground, it can re-sprout.”

However, what people can see the most are full-grown, 20-foot shrubs with probably the same width; then, the only option is to cut them down and spray herbicide on the stump. This will effectively kill the plant to its root.

People can replace those shrubs with any of the following native plants: spicebush, arrowwood, gray dogwood, winterberry, black haw and bayberry.

Haas also urges people to purchase plants from reputable sites and look up what are the native species.

“We discover something that we thought to be good but actually not, every single day,” Haas said. “If you have a choice to go out and plant something, make it a native plant.”