FROM THE GROUND UP: Beware of this pretty invasive

Blooming now. The beautiful flowers of the Carolina silverbell.
Blooming now. The beautiful flowers of the Carolina silverbell. PHOTO BY PAMELA BAXTER

Around Easter time, there are always a lot of ads advising parents against giving their children adorable chicks and bunnies as gifts unless they are prepared to bear the responsibility of caring for the animals. I think that there should be other public announcements each spring that warn homeowners of the risks of planting particular trees, shrubs, and vines. Too many of the most popular plants are invasive.

The botanical culprit I want to talk about today is the Bradford Callery pear (Pyrus calleryana), which was introduced as an ornamental tree by the US Department of Agriculture in 1964. I remember how it was described by my Woody Plant Materials professor at Temple University (Ambler). He spoke passionately about the beautiful white flowers in spring, glossy green leaves in summer, and gorgeous foliage in fall. The fruits were “insignificant,” meaning that they were so tiny you needn’t worry about having to rake them up. A medium-sized tree, reaching maybe thirty feet, it had plenty of applications in both home and urban settings.

In his 1977 “Manual of Woody Landscape Plants,” landscape plants guru Michael Dirr touted this new arrival as, “One of our finest street trees, lawn trees, and all-around general purpose plants; works well in malls and planters; very fine tree and has received wide acceptance in east coast landscaping. . . . I hope to see more in the future.”

Dirr’s wish came true: Bradford pears started showing up everywhere. No one seemed to mind that the flowers do not have a pleasant odor, and it was too soon to learn that the trees had an unfortunate flaw: weak branch crotches leave the trees susceptible to breaking. They don’t have a long lifespan.


I got to witness this first-hand after my neighbors planted three Bradford pears in their front yard — beautiful, just as promised! But it soon became apparent that the least bit of wind or ice was enough to bring down half a tree. After having this happen to two of the trees, my neighbors simply had the third removed.

Over time, another unfortunate trait has emerged with Bradford pears, and it’s far less benign. Remember the movie Jurassic Park, and how John Hammond and his team of scientists believed that the dinosaurs they were creating were sterile, but they weren’t? Something similar happened with the Bradford pears, and it has become a major problem.

Here’s what writer Durant Ashmore had to say in an article published by Greenville Online at “The problem is that these trees are in fact not sterile. No two Bradford pears will ever reproduce among themselves, but they do cross pollinate with every other pear tree out there.

“Because of the cross pollination problem, pear trees have now proliferated exponentially across our environment. To make matters worse, the evil offspring has reverted to the ancient Chinese Callery pears which form impenetrable thorny thickets that choke the life out of pines, dogwoods, maples, redbuds, oaks, hickories, etc,” Ashmore wrote.

Regarding the trees’ four-inch thorns, Ashmore notes, “They can’t be mowed down. Those thorns will shred John Deere tractor tires.” (

The Bradford pear is beautiful, sure, but it’s not worth it, especially when there are excellent alternatives, such as:

Carolina silverbell (Halesia carolina)

White Fringetree (Chionanthus virginicus)

Cranberry bush viburnum (Viburnum trilobum)

Serviceberry (Amelanchier arborea)

Kousa dogwood (Cornus kousa)

(In this list, all but the Kousa are native to the U.S.)

With so much information readily available on the Internet, you can research alternative species, find a nursery that stocks what you are looking for, or even ask your local nursery if they can get specific plant material for you. With a little advance planning, you can have a landscape that is both beautiful to you and also helpful to our environment and the wildlife that relies on it.

Note: Do you have an unusual or interesting garden? Of course you do! And I’d love to write about it. Send me an email. Please describe your garden, and let me know if you’d be willing to give me a tour.

Pam Baxter is an avid organic vegetable gardener who lives in Kimberton. Direct e-mail to, or send mail to P.O. Box 80, Kimberton, PA 19442. Join the conversation at “Chester County Roots,” a Facebook page for gardeners in the Delaware Valley. Go to Facebook, search for Chester County Roots, and “like” the page. To receive notice of updates, click or hover on “Liked” to set your preferences.