AUGUST
2009

 

 

 

By
B. Rosie Lerner
 
Purdue
Extension
Consumer Horticulturist

 

 

 

 

 

08-06-09

Question and Answer

Q. One of my neighbors recently peeled away a band of bark from his hickory, and I'm wondering if this is a preventative measure against insects or something? Should I be doing this to my hickories?

A. Let me preface my reply with the recommendation that most of you should NOT try this at home! Though the most reliable way to understand why your neighbor peeled the band of bark is to ask him, there are a couple of possible explanations. Depending on how deep one cuts into the tree, one could be either trying to promote fruiting or trying to kill the tree! The removal of a band of bark all around the circumference of a tree is called "girdling." Girdling to remove the bark and the very thin layer of tissue, just below the bark (phloem), is sometimes done to fruit and nut trees to reduce overly vigorous foliage growth, to induce earlier and more numerous flowers, and to improve fruit size and numbers. While not necessarily a fatal injury, this gaping wound is certainly a possible entry point for disease and insects and can eventually weaken the tree. But realize that commercial fruit production aims for quality and quantity of fruit, and trees are routinely scheduled for replacement.

Foresters sometimes use deeper girdling to actually cause tree death by cutting through bark, phloem and the next even thinner layer of tissue, known as cambium. But in a forest situation, there might be occasion to want to thin the stand without removing the tree.

These girdling techniques are not recommended for home gardeners.

Q. I recently found a garden forum where someone asked others to submit the plants they wish they had never planted. Among the plants submitted were asters and bleeding hearts. I understand why after having planted them only two years ago. They're easily triple their original size in their third year in my garden. How far can I cut them back right now (mid June), and can I transplant the asters without losing the autumn blooms, or do I have to wait until after the asters bloom to transplant them?

A. Ah, this just further illustrates how beauty is in the eye of the beholder! I personally embrace the ability of asters and bleeding hearts to fill space! Of course, by the time you read this, it will be much too late to cut the asters back without sacrificing autumn blooms. But for future reference, summer is not a good time to move the plants anyway because we usually experience hot, dry weather that would inhibit re-establishment. Early spring is the ideal time to move them, before or just as they make new growth. Granted, this summer has been a bit out of the ordinary, with cooler and wetter conditions than most years. But it's best to wait until late winter or early spring to transplant asters.

Q. We have one tree that died this spring and now the one beside it is dying also. The leaves are drying up and falling off. I think they are ash trees. Can you tell me whom to call to see if they can give me some answers? We don't want to loose any more trees if we can help it.

A. There are several Purdue offices that can provide assistance. First, contact the Purdue Extension agriculture educator in your county. The ag educator can help identify and assess the tree and determine if further diagnostic help is needed. Diagnostic service is available from the Purdue Plant & Pest Diagnostic Lab, http://www.ppdl.purdue.edu, and/or the Purdue Entomology Department Emerald Ash Borer Program, http://extension.entm.purdue.edu/EAB. You'll find contact information for all of the county offices of Purdue Extension at http://www.ag.purdue.edu/extension/Pages/Counties.aspx.
Q. Every year I plant cucumber seeds. They come up and grow to about 3-4 inches, and then they just die off. I have also tried buying the plants and the same thing happens after a few weeks. Can you tell me why this is happening? Thanks for you help.

A. Sounds like you might have a soil-borne fungus coupled with soil that is staying too wet. The young seedlings are likely being killed by damping off, a fungal disease that attacks seeds as they germinate. The seedlings may be killed before or after they emerge from the soil. If after, the stem at the soil line takes on a darkened, water-soaked appearance quickly followed by collapse and death of the plant. Damping off is not likely to attack transplants; however, similar fungal organisms cause root rot. Wet soils lacking in adequate aeration allow the fungi to thrive. Cold, wet soil leads to slower germination and root establishment, leaving plants more susceptible to attack. But some species of root fungus thrive in warm, wet soil.

You'll want to try growing cucumbers in either a completely different location on your property or perhaps in containers. The fungus overwinters in soil as well as on containers and tools so good sanitation practices are critical to preventing this problem in the future. You can buy seed that has been treated with a fungicide to help prevent damping off, but make sure you start with clean containers and media. Discard contaminated potting media and start with new, pasteurized mix. Sterilize containers and tools with diluted (5-10 percent) bleach solution before reusing.

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox,