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Ron Smith answers reader's questions about the world of plants and gardens.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I got a heartleaf philodendron from my best friend a few months ago. I don’t know why she gave it to me because I have a brown thumb! However, it was growing and looking beautiful, but, at Thanksgiving, my nephew grabbed ahold of it and pulled the plant out of the pot. I was heartbroken! I went on the Internet and found out how to replant it, but I think that I did something wrong because it looks like it is dying. The once beautiful leaves are turning yellow and then brown. I really need some advice on how to bring the plant back to its beautiful state! (e-mail reference)

A: The information you gave me is too thin to make an accurate diagnosis, but I can at least make some suggestions. Most houseplants succumb to overwatering or not getting enough light. If you are watering once a week on a regular basis, you probably are overwatering. If you live anywhere north of the Mason-Dixon line, the winter sunlight coming into a typical home will be too low to support a plant sufficiently, especially if you are continually watering as you were a few months ago. I would suggest getting a plant light and using it for 12 continuous hours a day between now and April 1. This is general cultural advice, with no assurances that following it will result in correcting the problem you describe.

Q: I was wondering if you know anything about royal frost birch. I have an old red leaf crabapple tree that has been having awful issues with apple rot and beetle damage. I would like to replace it because it is so difficult to maintain. Would you know if the royal frost birch is hardy or has disease problems? I assume Japanese beetles will be an issue because it has red leaves. Is there anything that works better than spraying Sevin on a weekly basis? It is doubtful we will ever rid ourselves of the beetles because we are surrounded by empty fields that are not maintained. Is the birch tree susceptible to animal damage? We have had deer eat the bark on a tulip tree and we often have rabbits in our yard. How tall does royal frost birch grow? Will it provide a lot of shade in the front yard? What is its life expectancy? Can it tolerate wind? We have lost four pear trees due to wind. We live in Indiana near the Michigan border, so we do have snow and cold to worry about. If you have any helpful information about this tree, I would really appreciate it. (e-mail reference)

A: Apparently this cultivar of birch has been introduced after my professional references were published. I can't give you any direct experience or research information on the tree, but from what I have found on the Web, all the growers have nothing but good things to say about it. There is a reference you can review at I cannot answer your specific question, but the fact that it is listed as hardy in zone 3 is a good testimonial to how tough the tree is. If you keep the root system moist and not soggy or droughty, it will reward you with more than 20 years of beauty!

Q: I have two Australian tree ferns in front of my house that are blocking the front windows. Can I cut them down and let them grow back or will they die if I do this? Do they transplant well if I can’t cut them? I can move them to a more shady and suitable location if necessary. Thank you for any help you can give me. I live in central Florida. (e-mail reference)

A: They can be cut back, dug up, divided or moved, so you shouldn't have any problems.

Q: I have a question about how to deal with black spot on roses. I have read most of the material on your Web site, but I was hoping to get more specific advice. I have seven rose bushes in my yard. The bushes were here when I moved in. I do not know a lot about growing roses. I also do not know the variety of roses I have, except that some of them are climbing. Three of the bushes are very old and large. My concern is that they all seem to have black spot to one degree or another. I have tried clipping off all of the infected areas and bagging it. However, it doesn’t take long for the new growth to become infected again. I am not sure if I have cut the bushes back enough when I did try to cut them off. I am wondering when and how would be the best time to deal with this. I have considered cutting them back to the ground now and hope the black spot will not return in the spring. However, I don't know if I want to lose all of that growth. Any advice you could offer would be greatly appreciated. (e-mail reference)

A: Assuming you live in a part of the country where rose bushes are not threatened by cold weather, you are free to cut them back now. This will remove a large part of the inoculum and make it easier to control this fungus disease. Also, as I'm sure you would anyway, clean up all rose leaf litter in the area. As you prune, try to cut out the smallest stems, especially the spindly ones, and open the center for better air circulation and sunlight penetration. Black spot is spread by splashing water, so when you water, do so using a drip irrigation system or slowly trickle the water around the base of the plant. Old, established bushes that you described will need water only under extreme drought conditions. Rose leaves are the most vulnerable to black spot fungus when they have just expanded, so an application with a suitable fungicide during the growth phases would provide protection. There are many products on the market to select from, but I'll make a couple of suggestions based on my experience. One is Ortho Rose Disease Control (Funginex), which claims to have some systemic action for up to two weeks. Another product is Bayer Advanced Garden Disease Control For Roses. Both products are a little pricey, but do the job. Old standbys, such as lime-sulfur, Ferti-lome Systemic Fungicide and Daconil, will do a good job as well. It all boils down to the timing. As new growth expands, make another application based on the product directions on the label. Your solution requires an integrated approach, which means controlling water splash, pruning to increase air and sunlight penetration, annual pruning to remove spindly or infected stems and, if necessary, digging the plant up and moving it to a better location where more sunlight can reach the plant, especially in the early morning hours.

Q: I have a pink and a white crepe myrtle. The pink looks beautiful, tall and is blooming great. The white tree has not bloomed, but is growing. What could be wrong and what should I do to promote its growth and blooming capability? (e-mail reference)

A: I'll make some suggestions, but you should check with the local county Extension Service office in your state. Go to and click on your state to locate the county office nearest to you to see if there is a horticulturist who can help you if my suggestions don't work. The location might not be getting enough sun to stimulate flower bud formation. The plant might be getting too high a dose of high-nitrogen fertilizer or the plant might be planted too deeply. This often happens, but the impact sometimes is not seen for a few years. Sometimes the only clue is a lack of flowering.

Q: My husband put twice the amount of fertilizer on our lawn than needed! It was a granulate fertilizer. What can I do to stop it from burning? I watered right after it happened. If you get the chance, let me know if there's something I can do. Thanks so much! (e-mail reference)

A: You did the right thing. Water heavily again when you can, which I hope you did the first time. If it was a good-quality fertilizer, there is a chance it will not burn, but the lawn will grow with a vengeance.

Q: I have hosta plants with holes in the leaves. I’ve been told my problem is slugs. How can I get rid of them? Also, my lawn is uneven and bumpy. I think night crawlers are causing the problem. (Webster, S.D.)

A: You are correct in both of your assumptions. There are a number of ways slugs can be controlled. There is the old recommendation of pouring beer in a shallow aluminum pie pan. Make sure the edge of the pan is at ground level so the slugs can crawl into it and drown. There also are a number of products on the market that are poisons. For visibly noted slugs, sprinkle some salt on them and they will expire quickly. With night crawlers, there is no product on the market that is labeled for them to my knowledge, but correctly assuming that everybody's lawn has a grub infestation to some degree, the application of a grub insecticide would bring the night crawler population down about 25 percent to 30 percent. Follow that up with a rolling using a ballast roller.

Q: I have a storeowner who says her poinsettia has white dots on the underside of the leaves and some of the leaves are curling. Do you have any idea what the problem is and how it can be corrected? She was wondering if they are some sort of insect egg. (e-mail reference)

A: Most likely the problem is scale insects. Get the owner to get some insecticidal soap. With rubber gloves on, soak a rag with the stuff and wipe the underside of the leaves off.

Q: I’ve had an apple tree for several years, but this year was the first year it had about a dozen apples on it. In late August, I noticed that all the apples where gone except two. I thought the neighbor kids had raided the tree. After further investigation, I found the apples lying on the ground in a pile of mush. The two apples still on the tree had large holes with bees feeding on the flesh. What happened and what do I do to prevent this next year? (Fargo, N.D.)

A: What probably happened is the apples were found and fed upon by apple maggots, which caused the apples to drop prematurely. The mature maggot is a fly that lays eggs just below the surface of the developing fruit. As the apple matures, the eggs hatch and the maggots tunnel through the fruit, causing the apple to drop in many cases. The quality of the fruit is compromised, which causes rotting to begin and attracts yellowjackets to feed. To prevent this from happening again, there are a couple of approaches to take. Follow good sanitation procedures by cleaning up the apple and leaf litter beneath the tree. You can use sticky traps of false apples to catch the female fly next spring. There is no way to kill the maggots after the apples are infested by the adult. Protect healthy apples by applying Sevin after the flower petals drop and again about every 10 days.

Q: I read an article that had suggestions from you on how to raise healthy trees. I have got a horseshoe-shaped shelter belt around my home. Last summer, one tree was very brown on the side that faces the house. This summer, there were 11 more that had some degree of browning. The browning always starts on the side that faces the house. A person from our local nursery said I had needle cast and would have to spray the trees. I then called our local Extension Service office to inquire about where to buy enough chemical to spray 150 trees. The Extension agent wanted to see the trees. He said they are planted too close together, so no air is circulating around the trees, which is causing the trees to turn brown. I might add that we have not had rain for a long time. He also said I shouldn't rule out drought damage, but I question that because it is only the trees on the north side of the house that turned brown. He told me I should remove every other tree. I should add that we had the trees planted by the Soil Conservation Service out of Aberdeen. Moving that many trees is going to be expensive, so I would like another opinion before I hire someone to start that process. (e-mail reference)

A: I think if you contact the SCS folks you will find that the spacing of the planting was meant to be temporary. As the trees began to grow and fill in, some of the trees should have been removed to allow for better air circulation. What I am surprised at is that the people who paid you a visit did not see any spider mite activity because it sounds like this is what your trees might be suffering from. No rain for a long period of time is a sure way for these pests to develop and do some devastating damage. We all tend to think in monocauses, when in fact there are likely multiple problems going on, such as drought damage, spider mite activity and possibly diplodia tip blight. These all are guesses. The only way to be sure before you invest a lot of money in spraying is to have the South Dakota State University Plant Diagnostic Lab folks check out what is going on. SDSU has very competent diagnosticians working and managing the lab.

Q: I bought some sweet corn that was really good. I saved a couple of ears to plant next year. How do I go about drying the kernels? (e-mail reference)

A: Sorry, it won't work. These are hybrid varieties that are good for one generation. You would get corn of some kind next year, but not the same quality as you enjoyed this year. The seed isn't expensive, so you are better off purchasing fresh seed every year.

Q: What is a good winter fertilizer for my yard? The company that sprays my yard during the summer suggests 28-10-10. Doesn't that seen high in nitrogen for a winter fertilizer? What would you suggest? Thanks. (e-mail reference)

A: It is a little high, but not excessive. Generally, it is the nitrogen and potassium (the first and last numbers in the analysis) that are responsible for conditioning the lawn for the winter. Be sure the source of nitrogen is not totally water soluble or else it will overstimulate the grass and keep it too lush and soft going into the winter months. The usual winterizer fertilizer that is marketed by Scotts is a 22-3-14, which reflects an adequate level of nitrogen with some timed-release or water-insoluble nitrogen and the higher levels of potassium. The phosphorus, which is relatively immobile, isn't needed at all at this time of year. If your lawn care operator applies what he has, no harm will come to your lawn unless the operator is using close to 100 percent water-soluble nitrogen.

Q: You have given me some good advice several times. Now I have a question about chives. I have a bed of them that is about 10 years old. This year, it did not do very well. Should the bed be dug up, separated and replanted every so often? (e-mail reference)

A: That’s a good idea to do with almost any herbaceous perennial. Otherwise, they are almost bulletproof!

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
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