Avoid planting invasive species into your landscapes

Monday, March 21, 2016

They sprinkle the landscape with blasts of white flowers and serve as a reminder that spring is here. Their beautiful blooms are appealing to the eye, not so much the nose, but definitely the eye.

Bradford pear trees, among other invasive species, have become a popular choice for landowners over the years to add beauty to their property. However, that beauty spreads like wildfire into other areas and chokes out native plant life.

“This attractive tree is common in landscapes across much of eastern Oklahoma and is beginning to invade adjacent prairie and forest openings,” said Dwayne Elmore, Oklahoma State University Cooperative Extension wildlife specialist.

This has been a popular ornamental in that they have early and abundant flowers and bright fall color. However, they are short-lived and are ravaged by Oklahoma winds and ice storms.

“Occasionally, the cultivars produce viable offspring (seed) that are much more fertile and seem to be more invasive,” said Karen Hickman, professor in OSU’s Department of Natural Resource Ecology and Management. “These trees are spreading rapidly from the original sites.”

This is the time of year when retailers and nurseries ramp up their tree, flower and shrub sales. Homeowners should be mindful of varieties friendly to Oklahoma’s natural environment.

“I always look forward to visiting my local plant nursery to see what is available that might fit somewhere around my home,” Elmore said. “However, every year I notice plants being sold that are invasive in Oklahoma or in surrounding states. Many of these plants are purchased by homeowners who may be unknowingly opening Pandora’s Box.”

Bradford pear (callery pear), Russian olive (autumn olive) and nonnative honeysuckle are some of the main culprits in Oklahoma.

“Honeysuckle, which may be one of several species of vines favored for their aggressive nature and bloom characteristics, is another plant that has escaped into our eastern forests,” said Elmore. “While there is a native honeysuckle that is an excellent choice, beware the Japanese honeysuckle.”

Water gardeners also should be diligent as several invasive plants are commonly sold in Oklahoma.

“Water hyacinth is at the top of the list,” he said. “This beautiful plant has already filled many rivers and lakes to our southeast. Gardeners should consider that some species that are not yet invasive in Oklahoma might become so in the future. If it’s a problem in an adjacent state, we may be at risk from that plant.”

When deciding what plants to choose for landscape purposes, homeowners should talk to their county Extension educator about options, visit the Oklahoma Invasive Plant Council at ok-invasive-plant-council.org/ or download the OSU Fact Sheet “Problem Horticultural Plants.”

“With a little knowledge and planning, homeowners can help protect native plants and wildlife by being diligent in their landscape choices,” Elmore said.