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Don Kinzler, Published May 13 2011

Hortiscope: Cold-hardy shrubs work best as barricade

Q: I was in your wine class last semester. I recall you talking a little bit about horticulture. My parents have some lilac bushes that need to be replaced because they are old and not in the best of shape. However, they do work well as a property line and snow barricade. What should they plant as replacements? They are looking for something that grows quickly. (Carrington, N.D.)

A: Good, cold-hardy shrubs that would do well in your situation are meadowlark, forsythia, European cotoneaster, nannyberry viburnum, Nanking cherry and amur honeysuckle. Except for the forsythia, they bear fruit.


Q: We planted two maple trees last year. When we looked at them recently, we noticed that some of the bark is peeling off. We found very small bugs under the bark. Could the bugs be causing the problem? Should we be putting some sort of insecticide on the trees just as a precaution? Thank you so very much for your consideration. (email reference)

A: From what you’ve told me, I cannot give you an accurate answer. Peeling bark is common on some maples, especially as they mature. I encourage you to contact the nursery where the trees were purchased to have them looked at. You also can contact the Extension agent in your county or a certified arborist in your community. Go to www.csrees.usda.gov/Extension to find an Extension agent. Failing that, go to www.treesaregood.com/findtreeservices/FindTreeCareService.aspx to find an arborist.


Q: We have a number of apricot trees of different varieties. They provide us with abundant fruit at different times. For the past two years, we had very few blossoms. I have not pruned them except to shape the trees. I am wondering if my failure to prune the trees might have something to do with the lack of blossoms. Does fruit production only occur on branches of a certain age, such as branches from the prior year or two’s growth? Do I need to prune the trees to generate new growth that will produce fruit? Thank you. (Fresno, Calif.)

A: You will get better, more locally focused information if you contact the county Extension agent where you live. Go to http://ucanr.org/County_Offices for contact information.


Q: I’m wondering if you could help me with a dead grass problem. What can I do to fix the dead patches on my son’s lawn caused by his two dogs? Thanks in advance if you have any suggestions. (email reference)

A: The way to control these spots is to dilute the urine by flooding them with water during the growing season. Do it as soon as possible after the dogs relieve themselves. See if your son can limit their activity to a spot that isn’t so noticeable. Other than these suggestions, I have nothing else of substance to offer. Sorry.


Q: Now that the snow is gone from the backyard, I found hundreds of small mounds of dirt. Are these mounds caused by night crawlers, moles or worms? How do take care of the problem? (email reference)

A: From your description, it sounds like a combination of problems. Digging/burrowing voles, ground squirrels and night crawlers could cause it. You need to examine the mounds to determine just what the cause may be. Generally, the mounds can be flattened with a ballast roller filled with water. If the mounds are quarter size in diameter, that would be evidence of past night crawler activity.

Once the soil warms above frost temperatures and the grass greens somewhat, these mounds might increase in number, which would be an indication of continued activity. It can be kept in check with an annual application of grub insecticide, which, through a period of three years of application, will or should get the population down to an acceptable level.


Q: I have three globe arborvitaes. This winter, heavy snow caused them to spread apart in the middle, so now they are severely out of shape. What can I do to get their round shape back? (email reference)

A: There really is nothing you can do. Allow them to grow as they are. If they are going to return to their original globe shape, they will do so during the growing season. Perhaps you can, with skill, selectively prune them to return to that form a little faster.


Q: Can you answer a question on Juneberries? A client would like to know what he could spray on his Juneberries so they don’t dry prematurely. Someone told him he may have bugs, but he cannot see any. That is all the information he gave me. Thanks for your help! (email reference)

A: The insects would not be around on his shrub right now because they show up at the time of flowering. The problem could be blueberry maggots or plum curculio maggots. Go to www.dowagro.com/usag/delegateradiant/delegate/berries.htm for suggestions on what insecticides to consider.


Q: I received a lovely dieffenbachia recently. However, it had a good infestation of mealy bugs. Upon the advice of a horticulturist friend, I bathed the plant in a mild soapy solution, removed all the old soil from the roots and transplanted it into a larger pot using fresh soil combined with a little compost. It is doing well and I have been monitoring it daily for any more bugs. This morning, I noticed a jack-in-the-pulpit growth on one of the top leaves. Is this a flower and is this normal? I was not aware that dieffenbachias flowered. Is there anything I should be doing differently? (email reference)

A: That is the intended flower of the plant. They flower about once every 100 years in a typical home environment, so count this as your one shot to witness this. Be thankful that it has enough energy to produce a flower.


Q: Would it be too early to core aerate my lawn? I’m chomping at the bit but feel like I should wait until growth that is more active occurs and follow the aerating with mowing and fertilizing. Is this a wise idea? Should I be waiting until the soil warms up and dries a bit? (email reference)

A: Give the grass a chance to green up and reactivate its root system before core aerating. If you want to do something, rake the lawn to get the trash and litter off and get the surface exposed to the warming spring sunshine. After you’ve mowed it at least once, go ahead and core aerate/power rake. Doing this aggressive operation too early shifts the environmental advantage to weed seeds.


Q: We have nine birch trees on our property. I love the beauty of the trees, but they are so messy. The dried seeds from the trees scatter from the pods beginning in midsummer. They clog our gutters and window tracks. They cling to our shoes and then are tracked into the house. On top of the seeds, small twigs consistently break off during moderate wind days. Do you get the picture that we are getting tired of the maintenance? We are so tired that we are considering taking all of them out. However, that seems so wrong because they are beautiful trees. (email reference)

A: I’m glad you talked to me before you had these native beauties removed! Yes, they do require some maintenance, but all living trees do. It seems that more and more, folks want maintenance- free plants. What I would suggest is that you contact a local certified arborist to have the situation analyzed. Perhaps selective pruning and a hormonal spray that is timed just right for your region of the country can greatly reduce the problems you and your hubby are experiencing. Go to www.treesaregood.com/findtreeservices/FindTreeCareService.aspx to find an arborist.

Too often, homeowners don’t realize just what a contribution to the property and neighborhood that mature trees make. I have two beautiful trees in my front yard. I have a standing contract with a local arborist who is a fraction of my age to come every spring after the trees have leafed out to do selective pruning. We also have screens over our gutters. Good luck, and I hope the arborist can work with you to keep most, if not all, of the trees you have.


Q: The home we moved into has four beautiful hydrangea bushes that bloom gorgeous blue flowers. In early fall, my landscaper cut down the dried hydrangeas all the way to the bottom of the plant. Now that spring is around the corner, I’m quite concerned that he may have destroyed the hydrangeas. Can you offer any insight on the situation? (Westchester, N.Y.)

A: Find something else to worry about. If they were healthy last year, they should be breaking bud shortly and grow beautifully for you. What your landscaper did is a rite of passage for most in this species. They are cut back hard in the fall or early spring. In 30 days or less, depending on your local weather conditions, they should start blooming for you. If they are a species that only bloom on old wood, then all you will get is lush growth this season. In that case, keep the landscaper away from the plants this fall so you get flowering the following year.


Q: I have been looking for someone to help me select trees to plant on some property I own. The ground is primarily a course, heavy sand/soil mixture. At one time, the lot was mostly large pine trees. However, they were removed for construction purposes. A few of the pines still exist. I would like to repopulate the ground with deciduous trees that would provide some shade. One concern I have is finding a tree with a rooting system that will hold in the soil because we do have quite a bit of wind at times. Also, I would like to find a tree that grows rapidly.

I have considered hybrid maples, autumn blazes or red sunsets. Would these trees be a good choice? Do you have recommendations on planting and setting up an irrigation system? Thanks for your assistance. (Rehoboth Beach, Del.)

A: Go to http://ag.udel.edu/extension/index.php# to find your local Extension agent. The agent may be able to assist or hook you up with a horticulturist or arborist at the University of Delaware. Your selection is a sound one. We grow them in the Midwest with a lot of success. I just am not sure of how well they might do in your part of the country.


Q: I have cut down a problematic silver maple on my front boulevard. Would you give me some tips on digging out the stump? I cut it off about 10 feet off the ground, so I have some leverage to pull it out. I know I need to dig around it and cut off many roots. Cutting it off flush and grinding the stump is not an option. Thanks for your help. (email reference)

A: You have the correct approach in mind. Not knowing your age or physical condition, I would encourage you to take stock of the task before jumping right in. I’ve never known any of these removals attempted by homeowners to be a piece of cake. You might want to have a backup of some young, strong backs, arms and shoulders. Very likely, you will have to employ a truck with a chain attachment to tow it out or wrench it loose. Of course, the standing trunk you left for leverage will have to be cut to manageable handling sizes. Be sure to observe all the precautions when handling a chain saw. Remember that a chainsaw cuts wood very nicely until the chain becomes dull when it hits soil.


To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail ronald.smith@ndsu.edu.