Bradford pears

Bradford Pears

Most trees and shrubs are emerging from dormancy now, some displaying colorful flowers and others just starting to leaf out. Several native trees are producing flowers including the deep pinks of the redbuds (please see our last Nature Note if you missed it) and whites of the serviceberries which brighten gardens and roadsides. Several species of native maple are also producing red or rust flowers.

Unfortunately, one eye-catching tree in flower now has escaped cultivation and is invading sunny fields, forests, and roadsides. If you see an oval-shaped small to medium-sized tree with white flowers and dark branches growing upward, it is probably a Bradford pear. While the Bradford pear may look pretty right now, it is not a welcome addition to our landscape.

The Bradford pear is a deciduous tree and one of the first spring trees to bloom in Maryland. It is a very common cultivar of the Callery pear- which is also an invasive species to Maryland. The Bradford pear is a small to medium height which grows relatively fast to about 30’-50’ tall and 20’30’ wide. Its white flowers carry 5 petals grouped in clusters. Its leaves, like most pear leaves, are simple, alternate along the stems, with an oval or oblong shape and fine round toothing along the edge. The leaves appear shiny and leathery and the bark can seem very dark contrasting nicely with the flowers in spring. Their rapid growth, dense foliage, and a profusion of flowers made these pear trees a highly desirable tree for landscapes and they were planted widely along highways and new developments since they also tolerate most type of soils and partial shade.

While the original ‘Bradford’ pear that was introduced in Maryland was self-sterile (unable to receive pollen from the same cultivar), it now cross-pollinates with many other non-sterile Callery pear cultivars and produces viable seeds. These pears produce small round greenish-brown fruits between its thorns in early summer. Birds and small animals eat the Bradford pear’s fruits and then carry these now viable seeds into areas of wilderness. This has made the Bradford pear a highly invasive species and a considerable danger to native trees because it forms dense, thorny thickets in wild areas out-competing and preventing the growth of native plants such as Eastern redbud (Cercis canadensis) and serviceberry (Amalanchier canadensis).

The key take-away is to ensure that you only purchase and plant native flowers and trees. Several helpful apps can complement the information on the labels at nurseries when you look for new additions to your yard or garden. If you are specifically looking for a smallish tree with gorgeous white flowers, consider a serviceberry which also carries fruit in June which birds and many other small animals relish. Many serviceberry cultivars also offer a showy red autumn color.

SSD. Nature Note for 3/17/2023

TREE SHELTERS 2014

These are often used in reforestation projects to protect the seedling for three to five years until the tree enlarges above nearby weed competition or to the point where the tree is larger than the deer browse line. (It is best to wait for the tree to reach an 8-foot height before removing the shelter.) The seedling is first planted, then the shelter is placed to cover the young tree, supported by a wooden stake.

Finally a plastic mesh “bird net” is placed around the lip of the shelter to prevent birds from climbing into the shelter.

Tree shelters were developed in the United Kingdom in 1979 to protect hardwood seedlings. Most evergreens do not grow well in tree shelters. The shelter protects the seedling from animal browse, chemical spray, machinery, and the elements.

Tree shelters also shelter the young tree from vines, brambles, or other plants that would suffocate the young seedling. The shelters are made of a translucent material designed to allow sunshine to reach the small plant. This stimulates upwards growth of the young seedling, and as a result they typically grow 40 percent faster than a seedling outside a shelter. Some shelters also have small perforations to allow some air flow inside the enclosure. The tree shelter also provides a greenhouse effect, maintaining a fairly moist climate inside the tube which will benefit the seedling during periods of drought. Today there is a wide assortment of shelters on the market.

They come in a variety of colors and materials such as plastic, wood and bamboo. Once the seedling outgrows the shelter, the shelter is removed and often can be reused.

Sometimes the shelter is damaged and should be discarded. The plastic shelters can be recycled; the organic shelters will decompose.

Many studies cite that with good maintenance practices and the use of tree shelters, a plantation should achieve an 80 percent survival rate. Observations in Frederick County confirm these results

Nature Note for 3/17/2023