DECEMBER
2002

 

 

 

By
Beverly Shaw
 
Advanced
Master Gardener
Purdue University

 

 

 

 

 

12-5-02

Question and Answer

Q. My honeysuckle is pretty wild looking. Dare I cut it down this time of year, or should I just grin and bear it? -- Jean Phillips, Lafayette, Ind.

A. You won't kill it if you prune it now, but the cuts are areas that could dry out during winter. It's best to wait until spring, just before it leafs out if you're going to do drastic pruning. If you just want to tip it back a bit to keep it from being so wild, then go ahead and do it now.

Honeysuckles are hard to kill and tolerate heavy pruning well. I'm not sure if you have a honeysuckle vine or bush, but both can be cut back to 12 inches from the ground and will still spring back with vigor. They're so vigorous that you might want to think about whether this is the wrong plant for the spot. If it is always exceeding the space available, you might want to remove it instead of pruning it back.

Q. I have three rhododendron bushes that won't bloom. They are 3 or 4 years old, and, this spring, I had only one bloom on one plant. They are planted on the west side of the house and near a large pine tree. They don't get much sun. Do you have any suggestions? -- Stan Bennett

A. Rhododendrons cover a large portion of the United States, and there's a great deal of variability in the hardiness of different rhodos. It's important to choose the right plant for your climate. The American Rhododendron Society lists recommended species and cultivars on its Web site at www.rhododendron.org. Look for the proven performers for Indiana. It's a good list, but we all seem to suffer from plant envy (sometimes called hardiness zone denial) and choose plants on other state lists!

Even if the buds on your rhododendron are usually hardy to your area, the temperatures in recent winters could have been a problem. Late spring cold snaps can damage buds, in which case you would see the damaged buds but not get any blossoms.

Hardiness is only one possibility. Some cultivars require some sun for flower production while others like more shade. Yours could be suffering from a lack of sunlight. It would be helpful to increase the amount of morning sun on the plants, if possible. Be careful, though, because winter sun on an evergreen rhododendron can cause desiccation.

Finally, your plants may be just settling in. They're fairly young, and rhododendrons can establish slowly. With regular water, nutrition and decent temperatures, they could put on quite a show next spring.

Q. I am a true blue reader of your column. I never knew that hens and chicks bloomed, but as you can see in my photo, they do. I have a very sick dogwood tree. It has split bark. What can I do? -- Doug Hall, Celestine, Ind.

A. Dogwoods are susceptible to a handful of pests and diseases. Take a sample of the branches to the Purdue Extension office in your county for diagnosis so that you know how to treat the tree. There's no sense in spending the time, energy and dollars, as well as exposing yourself to pesticides, just to spray an insecticide on a plant with a disease or a fungicide on a plant riddled with insects.

It's possible that your tree has dogwood borer. The larvae enter through a wound in the bark, like those caused by lawnmowers on trunks. Once inside, the larvae feed in the inner bark. The damaged area of the trunk swells until the bark falls off. This may not kill the tree in the first year, but years of reinfestation will cause the tree's demise.

Check the main trunk and branches in early spring and early fall for signs of dogwood borer. Infested trees develop seeping cracks that contain piles of sawdust-like frass. If dogwood borers are a chronic problem in your area, you can apply an annual borer spray in early May. Follow all label instructions regarding amounts of pesticide to use, method of application and safety warnings. For information on insecticides for dogwood borer, refer to publication E-41, "Recommendations for Managing Insects and Mites on Shade Trees and Shrubs," which is available from the Purdue Extension office in your county.

In addition, some cultural practices will reduce borer injury. Regularly watered and fertilized trees remain vigorous and are less susceptible to borer injury. Avoid pruning during the summer months when the moths are laying eggs, and avoid wounding or injuring the tree.

Another possibility is sunscald. This occurs when thin-barked trees receive winter sun. The southern surface warms more than the bark on the northern surface. A sudden drop in temperature can make the plant cells rupture, causing damage to the bark. Prevent sunscald by wrapping the trunks with burlap or a commercially available tree wrap.

Thanks for sending the photo of the Sempervivum, or hens and chicks. These are interesting plants, and many people collect them. The parent plant, or hen, creates many chicks, or offsets, that are easily plucked off and transplanted. When they bloom, typically in summer, they send up a tall, alien-looking flower stalk. The rosette that bore the flower typically dies, but the offsets live on.

Q. I realize you are a gardener, but I hope you can answer my question. What kind of spider makes webs between trees and other close objects? I live in the woods, and every year these pesky spiders make a walk in the woods a challenge. The spider is very dark in color and looks like it has some sort of shell or large thing on the rear part of its body. I just want to cure my curiosity. -- Gordon Vander Ploeg, DeMotte, Ind.

A. I asked an entomologist, and he said that it could be one of dozens of spiders! He recommended purchasing the "Golden Guide to Spiders," one of the commonly available, inexpensive nature guides, to aid you in your quest for identification. My sister lives in Canada and has the same situation, although it's probably caused by a different spider. When visiting, we walk the path to the lake each morning waving a stick before us!

 

Contact: B. Rosie Lerner
Editor: Olivia Maddox,