Stop Planting! Stop Planting! STOP PLANTING!!!!March 30th, 2015
Did you really plant that? Or perhaps, did you really buy that? Did you really order that? Did you really grow that? Did you really think the Bradford Pear was the ideal tree you were looking for? Seems a little harsh?
Not really- the Bradford Pear – Pyrus calleryana and all of its sister cultivars are proving to be a difficult habit to break for suburban homeowners. I will grant you the tree does have some nice attributes, glossy leaves, bright white flowers and amazing fall color. Certainly all characteristics which we place value in when we are choosing that special tree or trees for our own yards. We, the horticulture industry, have gotten smarter over the years, realizing some problems with the ‘Bradford’ cultivar itself – mainly its propensity to split and fall apart after a heavy windstorm once they begin to mature. We solved this issue with better branched cultivars, more open growing habits and less dense branching patterns. No sooner than we resolved that weakness of the pear, we discovered another one here in the Midwest. All Callery Pears, Bradford, Aristrocrat, Red Spire, Whitehouse & Capital to just name a few are susceptible to Fire Blight. What is Fire Blight? Fire Blight is a bacterium which gets spreads at time of flowering between trees. Starting on the East coast, fire blight has made its way to Missouri – a disease we rarely worried about twenty years ago. Easy signs to recognize are wilted or brown/black flower structures which droop at the tips of the branches. As the blight persists, the tree becomes covered with “burned” branch tips and leaves. Ultimately spreading throughout the tree and killing it. Control of the fire blight is difficult at best- the time to treat is at flowering- the exact time that our insect pollinators are busy doing their jobs at the very same time. Argghh – bad news for one our most heavily planted ornamental trees.
Ironically perhaps, the Callery Pear was first brought to our country from China and Korea in the early 1900’s. According to Dr. Michael Dirr, the Callery Pear was brought here in hopes of breading in resistance to fire blight for our fruiting varities of native pear. As spring makes its long awaited return here in St Louis, keep a watchful eye out for the beautiful white flowering pears all across our town. Notice where they are, so in another 6-8 weeks you can begin to notice the impact the fire blight is and will continue to have on our pears. Fire Blight can attack all members of Rosaceae family: Pears, Apples, Cherries, Plums, Pyracantha, Roses, Hawthorn, Serviceberry, Quince and others. So it only seems logical that we look for other cultivars which have resistance to fire blight before this blight thing gets out of hand.
From bad to worse… as if the above discussion was not enough, with all of the pears being planted in suburban areas, open pollination of flowers between pear trees and pear cultivars have created a plethora of fruit for our birds to enjoy in the winter time. The resulting dispersal of pears seed indiscriminately across open fields and right of ways has introduced a new invasive species into the Missouri landscape. These pear volunteers are colonizing highway right of ways in St Louis County and out state Missouri alike. So much so that the Callery Pear has appeared on the list of non-native plant species threatening the Mark Twain National Forest. As the pear volunteers spread, so does the fire blight – so will the impact on our native forests and urban landscapes alike. Arggghhhh!
Stop planting – not really, just stop planting the non-natives. Look for Autumn Brilliance or Robin Hill Serviceberry as a great native substitute. Enjoy the Spring. CGC
“When the World wearies, and Society ceases to satisfy, there is always the Garden”