Bradford Pear Troubles

The following questions were sent to the P&PDL diagnosticians here at Purdue University:

Question 1: We have seven beautiful Bradford Pear trees in our yard -- six in the back and one in the front. The one in the front split and during a good storm last year, half of it fell over. We were able to cut the remaining limbs back and are in the process of trying to salvage the tree.

Our problem is that the tree service person said we need to top and trim the remaining trees because they have grown too big and the same fate (toppling over) may befall them as well. Why have these trees supposedly grown too big? And why do then need to be topped and trimmed? Is it necessary? Please advise.

Answer 1: The splitting of the Bradford pear is a very common problem. It's not that it just suddenly happened, it's just that it finally got too large and the limbs too heavy. The way they grow, - with very "v" shaped crotches, lends it self to this problem..

The very last thing you want to do is top them. What you want to do is thin out the branches at the crotches. This will relieve the stress and weight above.

When you top a tree, you interrupt the natural hormone balance. The terminal buds ( buds at the very end of the branch) produce a chemical called auxin. This reduces shoot growth along the sides of the limb. If you cut off the terminal buds which happens when you top a tree, the auxin can no longer prevent this shoot growth. The result is an enormous amount of sprout growth from the point where the cut was made. This would create a huge amount of extra weight at the top of the tree where you want it the least.

Taking care of trees is a matter of understanding how they grow naturally and using that understanding when we take care of them - either pruning, fertilizing, mulching, whatever we do. This produces healthy beautiful trees that are so beneficial to us.

-Rita McKenzie, Urban Forester

Question 2: I am writing you from Lincoln NE and we have recently had a devastating snow storm that took approximately 66% of my bradford tree down. The remaining 33% is obviously growing to one side and is an eyesore. Is there any hope for the tree to make a recovery?

Answer 2: Bradford pears are extremely brittle in an ice or snow storm and I suspect the folks in Nebraska will observe this following their recent experience. I have observed this problem across the country and no longer recommend the bradford pear as a tree suitable for the Midwest. It is a shame that such a beautiful tree has a fatal flaw that does not show up until it gets larger and experiences an ice or snow storm.

There is little one can do if 66% of the tree has been lost. The plant will be a cripple the rest of it's life because of it's unique growth habit. My recommendation is to remove it and plant another species that is less susceptible to snow and ice damage.

Sorry for such discouraging news.

-Bruno Moser, Purdue University Horticulturist

Question 3: I have a Bradford Pear tree that is approximately 5 years old. This year it flowered OK and sprouted some beautiful deep green leaves. Now I have noticed some pretty severe deformities in the leaves. They are shriveling up and not normal looking at all. The tree is starting to appear thin in the foliage. Can you comment on what kinds of diseases affect pear trees here in New England, and how best to treat them?

Answer 3: Bradford pears will develop blackening of leaves from root stress problems (drought, too much water, root injury, etc). This is their form of leaf scorch. Fire blight is also a disease that affects Bradford pear. A sample would help determine the problem.

Question 4: My Bradford Pear did not flower in the spring. I have been told that planting another one would help. Is this true? If so, how close in proximity to the other should the new one be, and why will this help?

Answer 4: In general, plants must reach a certain physiological maturity in order to be capable of initiating a flower bud. It doesn't matter how many other trees are nearby, it won't help that tree become mature enough to flower. It is not unusual for ornamental trees to take five or more years to be old enough to bloom.

Once the tree is old enough to be capable of flowering, then they are affected by environmental aspects such as light, water, temperature, etc. (The notion of needing a nearby tree is more related to the cross-pollination needed by some plants for production of fruit.)

-Rosie Lerner, Purdue Consumer Horticulture Specialist