Posts tagged walnut

The deadly juglone of black walnut trees

The following is by Linn County Master Gardener, Claire Smith:

    The seeder wagon is in place.  The lawn mower towed it out of the shed down to the water way and then with two planks and my favorite son’s strong back we pushed and pulled it to the other side of the ditch.  With the addition of an old wire garden gate staked behind a sapling, a hand pump from my parent’s former home and a rock lined pseudo fire pit filled with Petunias that were on the end-of-season sale, the area reflects the peaceful primitive atmosphere I was striving for.  This is the area I mentioned in an earlier blog that became inaccessible to mow due to last year’s flood.  Hosta, native grasses and prairie perennials will grace the space next year.  We continued our zeroscaping to include a part of the road ditch that I learned is also impossible to mow after the mower and I suffered a close encounter with the culvert.  Now that waterway is filled with large rocks and what was a sloping grassy space is mulched. 

            Hosta will ring the two Black Walnut trees in the roadway ditch.  Hosta is a plant of choice there because I have some that need transplanting and they are not sensitive to Juglone, a chemical secretion from Black Walnut Trees. 

             Discovered in the 1880s, Juglone is produced in the fruit, leaves, branches and root system of several trees with Black Walnuts exhibiting the highest concentration.  The greatest intensity in the soil exists within the tree’s drip line, on an average 50 ft. radius from the trunk of a mature tree.  Plants susceptible to Juglone display yellowing leaves, wilting and eventual death.  Plants sensitive to Juglone include Peonies, Hydrangea, Asian Lilies, and Lilacs.  There are multiple choices that will withstand close proximity to Walnut trees such as most grasses, Phlox, Sedum, Daylilies, Iris and Hosta.

            Now my challenge is to determine plants that are not only resistant to Juglone, but also to the deer population in this neighborhood.  Unfortunately, Hosta is one of the critters’ favorite choices.  They have already decimated the Hosta and Bee Balm in the ditch on the other side of the lane.  A great winter  pastime will be comparison shopping perennials and grasses that are both deer and Juglone resistant as well as low maintenance for those landscapes. 

             I actually enjoy mowing.  And I like the challenge of creating and maintaining flower beds, but the  simple clean lines of zeroscaping does appeal to me.  A few plants and shrubs easily embellish the area without overstating the purpose of low maintenance.

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Answers to your questions and what about those tiny worms??

Cyndi Lee asked the following: I have found a large trail of what at first looked like sawdust, but upon closer examination are very tiny worm like things. They are falling from the large tree I have which overhangs our deck. Any idea what these are? They are very tiny and are falling in clumps. They are a pale yellow in color.

 If you know what the worms might be, please leave a reply below.

 Linn County Master Gardeners have answered some of the other questions you’ve been asking:

 Q: We have a small vine-like weed that is taking over the gardens and flower beds. they are small leafed the stems are strong and grow upon the plants and choke them off. I pull them constantly but they continue to grow back. Is there anything that I can spray them with without killing off the flowers and garden plants? I would appreciate your input.

ANSWER: Cut and paint cut end with undiluted Round Up.  Use a small foam brush.

 Q: I found a large worm on my mom’s apple trees and what to know if they are good worm or bad. where can I take then to find out? I can take them to Ames but where in Ames?????

ANSWER: Bring sample to Linn County Extension Office, 3279 7th Ave., Marion.  We’ll try to identify it here, or give info to ISU.

 Q: I am in need of help to get rid of the seedlings from my pear tree. I need to know when and how to manage them as I have a flowerbed under my tree. I did not put these in but inherited them from the previous owner. They are a nightmare to deal with. Thank you for your help.

ANSWER: They will need to be pulled out.

 Q: I have a beautiful Walnut tree but it has been sprouting branches near its bottom and just does not look right. Can I prune them now ? If so what angle? And should I put something on the exposed ends? Some of the branches are approx. an inch in diameter. I surely don’t want to harm my tree!

ANSWER: The tree is under stress for some reason.  Prune now.  Do not paint anything on wound.  It will heal itself.

 Linn County Master Gardeners also answer questions on Iowa State University extension’s horticulture hotline at (319) 447-0647.

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Your questions: tree talk

Readers have trees on their minds this month.

Dale, who lives in southeastern Wisconsin, submitted the following question: I have a beautiful Walnut tree but it has been sprouting branches near its
bottom and just does not look right.  Can I prune them now ? If so what angle? And should I put something on the exposed ends? Some of the branches are approx. an inch in diameter. I surely don’t want to harm my tree!

Teresa submitted the following: I am in need of help to get rid of the seedlings from my pear tree. I need to know when and how to manage them as I have a flowerbed under my tree. I did not put these in but inherited them from the previous owner. They are a nightmare to deal with. Thank you for your help.

If you have advice for Dale or Teresa, leave a comment below.

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