Yellow or Brown Leaves on Bradford Pear Trees: a Watering Problem?

Or Does the Problem Lie Elsewhere?

Image: proof that 2 plants can be the same type, growing next to each other, yet be different.
These two trees are the same type (Bradford pear) and growing right next to each other, yet one has fall foliage and the other doesn't. David Beaulieu

Bradford pear trees are subject to a number of problems (which is why experts argue against growing this cultivar), some of which may be signaled by the presence of either brown leaves or yellow leaves during a time of the year when a healthy specimen would have foliage of another color (typically, green in spring and summer, reddish in fall). What are the possible causes for such discoloration? Well, that will depend on a number of different factors.

By way of example, let's look at problems reported by two different readers.

Cause of Browning on Bradford Pear Trees: Underwatering, Overwatering, or Something Else?

Reader #1 lives in Michigan. He reports that he planted a Bradford pear tree in the summer, and that brown leaves and leaf-drop ensued. He wonders if it is due to overwatering or to a lack of water. Here was this author's response:

"My guess is that your biggest problem is not how much or how little water your Bradford pear tree (Pyrus calleryana 'Bradford') is getting, but rather the time of year you decided to plant it. Summer simply isn't the best time to plant trees. Generally speaking, spring and fall are the best times.

"But it is possible to be even more specific. Purdue University lists Bradford pear trees as one of the 'slow-to-root trees that should only be planted in spring.' The summer heat is very difficult for new trees to tolerate under the best of circumstances, and you can easily understand why this would be doubly true for plants that are slow to root.

Shade cloth or some other shelter you can rig up might help to some degree, affording protection from the blistering sun.

"Your Bradford pear tree is, then, probably just plain stressed out; the brown leaves may be due to something referred to as 'leaf scorch.' As to watering requirements for young Bradford pear trees, only approximations can be offered.

This is because a number of variables must be factored in (variables which the 'expert' offering advice has no way of knowing for your particular case), including soil type, for information on which please consult this article: How to Find Out Your Soil Type.

"Purdue offers such approximations when addressing the issue of watering newly-planted trees, recommending 1 inch of water per week for an optimal soil (that is, soil that is well-draining, but not excessively so), 2 inches for a sandy soil (where drainage is actually a little 'too good'), and less for a clay soil (which retains water well)."

You can learn more about planting or transplanting trees here.

After digesting all of the above information, you may want to take your reflections one stage further and contemplate a more fundamental issue: namely, the wisdom of planting Bradford pear trees, in the first place. Due to the susceptibility of their branches to breakage during snow storms, ice storms, or wind storms, they have fallen out of favor with the landscaping community. True, their dazzling displays of white flowers are impressive in spring, and they are good fall foliage trees. However, wonderful substitutes are now available, such as Pyrus calleryana 'Autumn Blaze.'

Possible Causes for Bradford Pear Trees' Leaves Turning Yellow in Spring

Reader #2 wrote in to ask, "My Bradford pear tree has yellow leaves this spring. Do you know what the problem could be? It is mid-April, and the leaves continuously turn yellow and fall off the branches, two or three of them at a time. Is my plant dying? What can I do, if anything, to solve this problem?" She received this response:

"When you see leaves turning yellow on a Bradford pear tree, it is always a good idea to rule out some kind of nutrient deficiency first (for example, an iron deficiency in the soil causes chlorosis in plants). Have your soil tested by sending a soil sample in to your county extension. If you do not understand their findings or recommendations, they will be happy to explain -- just ask.

"Have you ruled out a nutrient deficiency?

Yellow leaves on Bradford pear trees in spring could also be a sign of overwatering. In this case, the culprit could be either nature or you. That is:

  1. Has it been particularly rainy this spring in your region?
  2. How often have you been watering the plant?

"Whether the plant is receiving too much water from nature or from you, poor drainage is likely your bigger problem. Water will pass relatively quickly through a soil that drains well, and your plants are less likely to be adversely affected. If you have clay soil (which tends to retain water), you may need to improve the drainage and/or aerate the soil. If the specimen sits in a low spot, you may also need to improve the drainage.

"To aerate clay soil, you may have heard of puncturing the ground with an auger. To improve drainage, you could dig channels to facilitate run-off. The latter, of course, is more feasible in a mulched area than in a lawn area. But hopefully it is just a case where you have over-watered the plant and simply need to stop watering so much. The most that you should be watering a Bradford pear tree in the spring season, generally speaking, is twice a week. In fact, if it has been raining a lot, it might be best not to supply any supplemental watering at all."

But the Tree Right Next to This One Is Fine. How Can That Be?

Note that problems based in the soil (nutrient deficiencies, drainage problems, etc.) can be extremely localized. That is, just because the ground drains well in one location in your landscape, that does not mean that you may not have a drainage problem at another location in your yard -- even when the latter is just a few feet away from the former.

Likewise, not all plants are created equal. Take susceptibility to chlorosis, for example, the direct cause of which is partial failure to develop chlorophyll, but the indirect cause of which is an iron deficiency. One plant may develop chlorosis in the very same soil in which another plant is growing without problems. The University of Arizona Extension observes that "susceptibility to iron deficiency varies greatly between plants, and it is not uncommon to see a plant with severe iron deficiency growing adjacent to one in identical soil with no symptoms at all."

Consequently, never take it for granted that two trees of the same type that are growing right next to each other are necessarily going to turn out the same way. For an illustration of how erroneous such an assumption can be, simply check out the picture on the present page.