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Sharp drop in temperature may be a cause for concern in trees

Western Kansas experienced an extremely sharp drop in temperature recently. Temperatures in some areas of northwest Kansas were near 80 on Wednesday and dropped to near 20 or lower Friday morning. Unfortunately, trees were not hardened off before this happened. In other words, they were not ready for these cold temperatures.

What does this mean? You can read the whole article here in the Horticulture News. Go to this page and scroll down partway:

http://www.ksuhortnewsletter.org/

Tips and tricks on planting trees before you trick-or-treat

(Megan Kennelly, KSU Plant Pathology)

My family did a campfire and cooked our first pot of chili in awhile – it’s really feeling like fall! We have a few weeks remaining in October, and between now and Halloween is still a great time to plant trees and shrubs. Here are some articles with tricks of the trade before you trick-or-treat:

Nice summary from Johnson County:

https://www.johnson.k-state.edu/lawn-garden/agent-articles/trees-shrubs/planting-trees-shrubs-in-fall.html

Excellent nuts and bolts of tree planting:

https://www.bookstore.ksre.ksu.edu/pubs/MF3313.pdf

A few more details on methods:

https://www.bookstore.ksre.ksu.edu/pubs/mf402.pdf

Watering new trees and shrubs:

https://www.bookstore.ksre.ksu.edu/pubs/MF2800.pdf

Now, with all that, truly your most important FIRST step is deciding on what to plant. If you have not yet done your research on that question, here are some more resources on tree and shrub selection.

Trees and shrubs for difficult sites:

https://www.bookstore.ksre.ksu.edu/pubs/MF2205.PDF

Trees for Northeast Kansas:

https://www.kansasforests.org/community_forestry/community_docs/NE%20Kansas%20Preferred%20Trees.pdf

Trees for Northwest Kansas:

https://www.kansasforests.org/community_forestry/community_docs/NW%20Preferred%20Trees122016.pdf

Trees for Southwest Kansas:

https://www.kansasforests.org/community_forestry/community_docs/Pref%20Trees%20SW.pdf

Water-wise plants for south central Kansas:

https://www.sedgwick.k-state.edu/gardening-lawn-care/documents/Water%20Wise%20Plants%202015.pdf

 

 

Goldilocks and the three trees. (Site conditions that are “just right.”)

When it comes to trees:

Trees need water. Not too much, not too little, but just right.

Trees need appropriate temperature. Not too hot, not too cold, but just right.

Trees need to prune. Not too much, not too little, but just right.

If you are looking for some cozy winter reading, you can check out our publication about Tree and Shrub Problems in Kansas.

In addition, I just came across a great publication from University of Kentucky that discusses tree and shrub decline. The information is similar to parts of the Tree and Shrub Problems in Kansas book, but sometimes it is helpful to read information from a new source since everyone presents information in a slightly different way. The reference is Stress and Decline in Woody Plants.

Happy reading!

 

 

The case of the exploding bark

(Megan Kennelly, KSU Plant Pathology)

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This post’s info and photos are by Beth McKinzie, our diagnostic lab intern for the summer. Judy O’Mara, our lab director, is mentoring Beth.

The London planetree, Platanus x acrerifolia sheds its bark mid-summer in Kansas. This is a normal phase for the London planetree. A similar pattern can be observed with Sycamore trees, Platanus occidentalis which shed their bark, but not as extensively as seen on the London planetree. Both are in the same family, Platanus. There are many theories to why these trees shed there bark, which you can read about here (https://www.nycgovparks.org/news/daily-plant?id=19242). As this is a normal for these trees no management would be recommended.

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Trees losing leaves from summer stress

The following article is by Ward Upham, Dept Horticulture and Natural Resources:

 

There are three situations we may run into regarding tree leaf loss this summer.  The tree may produce yellow leaves scattered throughout the canopy of the tree, all the leaves on a tree may turn yellow and drop or the leaves may turn brown but stick to the branches.

If falling leaves are well distributed throughout the tree and result in a general thinning of the leaves, the problem is not serious.  Trees will often set more leaves in the spring than they can support during the summer. Heat and drought stress will cause the tree to lose leaves that it cannot support with the available soil moisture.  Leaves that drop are most often yellow with no discernible disease spots. However, at times, we can have green leaves drop that appear perfectly healthy.  As long as the leaf drop results in a gradual thinning of the leaves, the tree should be fine if it is kept watered during dry periods.

In some cases we may see virtually all of the leaves drop.  Certain trees such as hackberry can drop all of the leaves and enter summer dormancy. We are a bit early for this to occur but may happen later in the summer if the dry, hot weather continues.  Trees that are summer dormant should have supple twigs and healthy buds. Usually, the effect on the health of the tree is very minor and the tree leafs out normally next spring.   As long as the tree has enough stored energy reserves to make it through to next spring, it will survive.  The twigs and buds tell the story.  If the buds die and the twigs become brittle, at least that part of the tree is dead.

The last case involves trees that have leaves that die and remain attached to the tree. This can happen seemingly overnight.  In such cases, the tree couldn’t keep up with moisture demands and died quickly.  This year, the cause may be due to excessive rains this spring damaging root systems.   As in the last case, the twigs and buds are the most important clue as to the health of the tree.  As long as the buds are alive and the twigs are supple, do not remove the tree, it still has life.

If you limited ability to water and need to prioritize, trees should come first because they are the most difficult and expensive to replace.  They also take the most time to reach an acceptable size.

Last week we had a couple of articles on watering trees.  You can find those articles at: http://hnr.k-state.edu/extension/info-center/newsletters/2016/June21_2016_25.pdf  (Ward Upham)