Pretty problems from Bradford pear trees

Wednesday, February 28, 2018

There are plenty of reasons people choose to plant Bradford pear trees on their property. They are the same reasons cities, parks, grocery stores and neighborhoods line roadways with them.

Their white flowers are beautiful in the early spring. They are extremely resilient and drought tolerant. They have excellent foliage all summer long, regardless of the terrible living conditions Oklahoma can throw at them.

All that is great, but there are some major downfalls to the tree. Some are obvious, like their awful smell, while others are a bit more subtle.

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,” said Dwayne Elmore, Oklahoma State University Cooperative Extension wildlife specialist. “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.”

Invasiveness

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 rapidly invading adjacent prairie and forest openings,” said Elmore.

While these trees can’t literally pack their bags and move from a backyard to an open prairie, they do have a particular set of characteristics that allow for easy spreading.

“The reason they are so gorgeous is because they have a ton of flowers, but then the ton of flowers turn into a ton of fruit, and the fruit is loved by the birds, which spread it everywhere,” said Lou Anella, a professor in OSU’s Department of Horticulture and Landscape Architecture and director of The Botanic Garden at OSU. “Some other plants have seeds that will just fall straight down and most of them will die in the shade of the plants they are under.”

Bradford pear trees are adapted for Oklahoma climatic conditions.

“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.”

Some of the more popular places to find the thorny seedling versions of the commercially produced and often planted Bradford pear trees are along fence rows and below power lines, both common hangouts for defecating birds.

“Literally, a bird was sitting on that high line and pooped a seed out,” Anella said. “The birds spread them everywhere.”

Weak structure

Bradford pear trees have been a popular ornamental because they have early and abundant flowers and bright fall color. However, they are short-lived and are easily ravaged by Oklahoma winds and ice storms.

As a Bradford pear tree grows, it forms a lot of branches in the same area, creating a weak spot. While the flowers are pretty, the narrow branch angles and density of branches in the same area create weak spots, often causing the tree to split.

“Bradford pears break up when they get old,” said Anella. “They have very, very weak branch structure and they fall apart.”

A heavy wind, much less a tornado, would be crippling to adult Bradford pear trees. That is not good news for a tree that can reach 30 feet tall and 20 feet wide.

“Also, due to their dense growth form, they are a terrible choice for public places such as shopping center parking lots,” Elmore said. “They tend to congregate birds such as starling and grackles, which then defecate on automobiles.”

Treatment

The best advice is to just not plant Bradford pear trees, but sometimes it is too late for that.

“If you have just small seedlings, mowing or burning can kill the seedlings,” said Elmore. “But once you have established trees, they’ll resprout so you have to use some type of herbicide control to keep them from sprouting.”

Trees can be cut down, followed by a herbicide treatment to the remaining base, or the chemical can be injected into the stem. Either option is significantly better than just leaving them alone.

“I would highly encourage people not to plant them, and to remove them if they already have planted them,” Elmore said. “Consider enjoying the blossoms one more time this spring and then as soon as the flowers fade, remove the tree before it seeds.”

Alternative selections

As the word continues to spread about the downsides to Bradford pear trees, homeowners are looking for alternatives. OSU fact sheet “Problem Horticultural Plants” lists the Eastern redbud, American plum, Mexican plum and Carolina buckthorn as good choices.

Options for replacements are good to have as some plant nurseries, like Big Creek Nursery and Landscape, LLC, in Stillwater, Oklahoma, have begun trying to turn people away from the Bradfords.

“We do not stock them, but we will sometimes special order them. The demand is still quite high, but we are trying to turn people onto other varieties,” said Big Creek owner/manager, J.D. Oldsen. “I discourage people from buying that tree, because for the most part, it is a tree that needs to disappear.”

When deciding what plants to choose for landscape purposes, homeowners should talk to their county Extension educator about options or visit the Oklahoma Invasive Plant Council at ok-invasive-plant-council.org/.

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