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Don Kinzler, Published April 13 2012

Hortiscope: Check label on grass-control product first

Q: A couple of years ago, we moved into a home that had a medium-sized flowerbed. The previous owner let it go, so it was full of weeds. We rototilled it and sprayed it with Roundup. We transplanted hostas, cone flowers, tulips and some other perennials. However, the grass has taken over again and we cannot keep up with it.

Is there a product we can spray on the flowerbed that will not hurt the flowers? I saw in a recent column you suggested using Poast. Could we use this on the flowers? (email)

A: Look for a grass-control product that contains Sethoxydim as the active ingredient. There are several on the market that have various concentrations.

The label will tell you what plants the product can be used on without causing any damage. Check the labels carefully and follow the instructions. This should help you spare your back and knees more pain.

Q: We have a red maple that is 38 years old. It’s gorgeous and gives us wonderful shade on the east, front and side of our house. However, its roots are now very close to the foundation of the house. The front walk and driveway are cracking. Is there any solution other than removing the tree?

Our local tree service says it must come out or risk foundation damage. Before killing something so beautiful, I need to know if there is another solution, such as cutting roots. What tree can be planted to replace this beautiful tree that will not do the same thing?

We recently had to remove a willow oak about 15 feet from the rear of the house for the same reason. It was huge, beautiful and healthy, but it could have been a problem if a major storm knocked it over (happened with its twin).

Those of us who don’t know any better have trees planted too close to our homes. I wish we’d known. They were so small when young and we thought we’d never get shade. Now we are dealing with multiple tree removals. Any tree replacement suggestions would be appreciated. Thank you for all the advice you give to the public. (email)

A: There are other approaches that can be used to save the tree. To correct a misconception about roots, they are opportunistic characters that will take the easiest way through the soil. Roots will follow the balance of air and water the soil contains.

A concrete foundation that is not leaking will not be threatened by any roots. Roots will be a problem if the soil along the foundation is kept moist and there are hairline cracks in the foundation.

For the sidewalk, the roots can be cut and the sidewalk reset or replaced. The addition of BioBarrier between the sidewalk and the tree roots will prevent any further root invasion.

To get information on this barrier, go to www.bio

barrier.com. In other words, keep this beautiful tree! My house is surrounded by large trees that are 6 to 8 feet from the foundation and paved surfaces. They have grown into beautiful specimens during the past 25 years.

Q: My Christmas cactus has grown very large through the years. I have made several plants out of the big one. I am wondering if some of the stems never will grow flowers or if they all are capable of flowering. I get lots of them throughout the plant but about 25 percent of the stems don’t have flowers. (email)

A: Your old Christmas cactus is probably exhibiting apical dominance on some of the branches. This process is a hormonal imbalance between auxin in the tips of the branches and the cytokinins that are produced in the roots.

There is a product available called Configure that is used in greenhouses to maximize Christmas cactus flowering. It does this by altering the balance in favor of the cytokinins to cause the blooming to increase.

For the homeowner, this might be accomplished by cutting off the top cladode (segment) of the nonflowering branches to see if this will stimulate more flowering.

If you have a friend in the greenhouse business, you might try asking for some Configure to use yourself or have your plant treated with the material during an in-house visit.

Q: I received a ficus tree at my sister’s funeral three years ago. I have it inside, and it has done well. However, for some reason, it’s not looking so good right now. It would devastate me if this tree died. I noticed a couple of branches are dead and the leaves on top are shriveled. I took the tree out of the pot and added gravel to the bottom of the pot and use distilled water at room temperature to water it.

Am I at a dead end? I’m sending a photo. Please help. (email)

A: The gravel will make matters worse in an already bad situation. The plant doesn’t look long for this world. Without knowing what is killing it, I am unable to give you any sound advice.

As an outside hope, scratch some of the more mature branches to see if the cambium is still alive under the bark. If so, then knock the plant out of the current container and repot it using fresh potting soil. Be sure to get the gravel out of the pot.

If possible, move the plant outdoors when the weather stabilizes to see if it will revive. Don’t overwater or fertilize the tree. If the cambium is not green, then the tree is dead.

You can always get another ficus tree to grow in memory of your sister.

Q: I have a lot of small trees in my big flowerbed. I cut all of them off last year and treated the cuts with some chemical. It almost looks like the small trees grew during the winter. Can I cut them down when the temperatures are in the 60s and then treat the cuts with another chemical? What would you recommend?

Thanks. (email)

A: I recommend that you find out if you are dealing with seedlings or suckers coming up from the roots of some trees. I suspect it is the latter.

If I’m correct, you will need to purchase a material called “Sucker Stopper RTU” to spray on the cut surfaces right after you prune them off. The material will keep the growth from coming back for the remainder of the growing season.

Q: Last year, the leaves and fruit (peaches, cherries and plums) started falling off my trees before the fruit was mature. What caused this?

We did not have a lot of rain last summer here in the midwestern part of Illinois. Could the lack of moisture cause this problem? Do fruit trees require a lot of rain?

We tried to spray as much as possible between the winds with Ferti-Lome Fruit Tree Spray using 1 ounce of product added to a gallon of water. However, we still had insect problems.

Also, must the fruit trees be sprayed immediately after it rains even if it is more than seven days between spraying intervals?

Also, thank you so much for answering and solving my problem when the lower greenery of my bom bon plant turned brown. The plant is beautiful this year. The browning must have happened because of the salt used on the sidewalk to melt the ice and snow and to overwatering in the summer. (email)

A: You need to get a fruit tree spray schedule established. Your local Extension Service agent can help you with that. Because you didn’t give me your exact location, go to www.csrees.usda.gov/

Extension/ to find the contact information for your area.

Knowing which species of fruit you are concerned about and the symptoms will go a long way in getting the problems identified and properly controlled. I’m glad my advice helped to solve the other problem you were having. Thanks for letting me know.

Q: I have two Colorado blue spruce trees in my yard that were planted in 1994.

They were beautiful. However, during the winter, one tree turned brown, but the other tree looks fine. I was told the brown tree has rhizosphaera needle cast.

Will the tree survive if it is treated for the problem or should we have it removed? I would like to save the tree if possible. Thank you for your knowledge. (Illinois)

A: Needle cast can debilitate a tree slowly to the point that one would want to take it down before it dies. You should get the tree checked by the plant diagnostic lab at the University of Illinois. Go to http://web.

extension.illinois.edu/state/findoffice.html for details on how to submit a sample for analysis.

It is extremely important that the pathogen be identified properly so the tree gets the proper treatment.

Q: How extensive are the root systems for green giant and steeplechase arborvitaes? I’m considering about planting a few that would be near our geothermal wells, so I want to make certain they won’t cause a problem. I think I’ll be able to plant them far enough away from the wells, but I want to be certain.

What is the range of how tall the steeplechase can grow? Is it advisable to plant these arborvitae trees near a fence? In other words, would shade from the fence cause any concern?

Would the green giant and steeplechase be a good choice for where it is windy and cold? I would like to use them as a windbreak. I’ve read that techny arborvitae is very wind- and cold-resistant. (email)

A: Steeplechase and green giant are cut from the same genetic bolt of cloth.

They will get to about 25 feet in height and 12 to 14 feet in width in about 10 years. Both are cold-hardy. All arborvitae species are fibrously rooted, which makes them popular with housing contractors because they are easy to transplant.

The side of the arborvitaes that will be against the fence will thin and die eventually. This is normal for any evergreen.

My advice is general and based on upper Midwest growing conditions. Any significant deviation from this location will influence the growth of these plants, such as bigger or smaller and faster or slower. If you live north of zones 4 or 5, you should not use either of those arborvitaes. If you live north of zones 4 and 5, get eastern arborvitae cultivars such as Brandon or technito.

Q: I thoroughly enjoy reading your column in our paper. I have a question about transplanting shrubs. Due to the unseasonably warm weather we’ve had in the past couple of weeks, many of my shrubs have buds and some are beginning to leaf out.

I need to move several of them. I have a few lilacs that also need to be relocated. They are large enough that we will be using a tree spade to move them. Should I wait to move them until after they’ve bloomed to avoid losing that feature this year? I also have some smaller shrubs (some flowering, some not) that I need to transplant. (email)

A: Moving them now as they are leafing out will cause wilting and possible viable bloom loss. If you can wait, a fall transplanting is recommended as being a better time. The best time is Labor Day weekend or one week before or after.

The same applies to your smaller shrubs. If you can get them out of the ground with the roots 100 percent intact and planted right away, you should be able to get away with moving them now.

Q: We are having problems with many of our pine trees in our shelterbelt. The needles are brown, and the trees look like they are dying. The trees are more than 25 years old and have been doing great until this year. Please help. We have been-deep soaking them. Our underground water level is high. Thank you. (email)

A: This could be normal winter burn. However, if the water table is elevated, why are you soaking the trees? Even if the water table was not high, now is not a good time of the year to be soaking.

If the soil is dry and the roots are not moist when you do a physical check, then give them a shot of water and wait until things dry before watering again.

I can’t help you based on the information you provided. Please get in touch with your local Extension Service agent for assistance. Go to http://www.csrees.usda.gov/Extension/ and click on your state and then county to find your contact person.


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 email ronald.smith@ndsu.edu.