You are here: Home Columns Hortiscope Hortiscope
Document Actions


Ron Smith answers questions about flowers, trees, gardens and shrubs.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I planted tulip bulbs in a pot inside and I water it daily. It has been more than a month now, but there is no sign of plant generating anything. What should I do? (email reference)

A: Throw it out because very likely the bulb has rotted by now. My guess is that it did not receive a cold treatment before you made the purchase. They need to go through a dormant chilling, which takes place in the winter months. If that happens, the result is beautiful flowers in the spring.

Q: Upon researching Harrelson apple trees, I came upon your wonderful column. I am hoping that you can help us. Our Harrelson is dropping leaves. The leaves appear to get brownish or gray spots and then drop. The tree is losing many leaves daily. In fact, several small branches are bare. This started after the apples developed. A local garden center recommended a hormone treatment, so we poured a water-soluble product around the roots. That was about 10 days ago. So far, the situation has not changed much. We would appreciate any help or advice you could give us. (email reference)

A: Hormone treatments have very little to no value at all. This sounds like either apple scab or rust. If you could send me a photo or two of what you are talking about or a sample in the mail (not the best way), I could identify what is wrong with the tree and get the correct recommendation to you.

Q: Since you helped us save our linden tree from an early demise, I'm hoping you can give us some advice for a birch tree that appears a bit depressed. The tree wasn't doing well last year, either. We tried using the Jobe spikes, but they didn't do much. The tree still has some leaves, but some branches do not have leaves. Do you think there's any hope or should we put it out of its misery? Any advice you can provide would be most appreciated! (email reference)

A: Glad the earlier advice worked for your linden. I do not think there is much hope for this poor birch, though. It never will amount to anything you would want to remain on your property. I suggest having it removed at a suitable time. Sorry!

Q: I have a question about emerald green arborvitaes. We recently purchased 10 trees that we are intending to use as potted plants to border our terrace. As of yet, we have not planted the arborvitaes in the pots. Some of them are turning brown. Will they do well as potted plants or are we going about this the wrong way? Also, I am wondering if we were watering them too much. Our weather has been somewhat crazy. We have had a recent streak of 80-plus weather. We water the plants lightly in the evenings. Please help my trees. (Portland, Ore.)

A: Get ahold of your local Extension agent. For Oregon, go to - and click on your county office. Basically, interior browning is normal for arborvitaes. The outer foliage turning brown is a potential problem. Containerized evergreens are subject to more stress than those planted in the ground. Consequently, more attention needs to be paid to details, such as regular watering and fertilization.

Q: We planted a willow tree in 1990 with little knowledge of the proper place to plant it. It is in our yard and not near a water source such as a pond, river or lake. We have sandy soil. Every summer, the tree will drop many leaves. Do I need to water more? The tree is 40 to 50 feet tall and has a giant trunk. We do have a fire hydrant in our yard. Could the tree pose a problem with the water lines? The tree is majestic, and part of me hates to lose it. However, the more I learn about willows, I am worried it could cause problems. It has not caused a problem in 21 years. Any advice? (Anoka, Minn.)

A: Find something else to worry about! A 21-year-old willow is not suffering from a shortage of water. To ease your mind, get a certified arborist to do maintenance pruning for you. Leaf drop is normal during the summer stress period of high temperatures. If it has survived this long with no additional inputs, I’d say you have nothing to worry about.

Q: I am from southeastern South Dakota and wondering if you could help with my raspberry problem. I have both June- and ever-bearing raspberries in adjacent patches. For the last two years, I have had what appears to be anthracnose in the June-bearing variety. I purchased a chemical and was prepared to spray as soon as the leaves appeared on the existing canes this spring. Last fall, I trimmed out all the old canes. This spring, I had a lot of rabbit damage, so I thinned out those canes. Of the remaining canes, only one leafed out, so I was not able to spray. There are many new plants and they look healthy, but there are no second-year canes. The ever-bearing raspberries look fine, so I hope to get a crop. Do you have any idea what could have caused the death of all the June-bearing canes? Is there anything I should be doing now or this fall to prevent this from happening again next year? (email reference)

A: Without any plant samples to examine or put under a lab culture, all I can offer you is conjecture, which I don’t want to do. The fact that you are getting new growth from the crowns and rhizomes is a good sign. You did the right thing in getting all the dead canes out. Raspberries are weeds that produce fruit that is nutritious and we like to eat! To protect them from their own ambitions, I recommend an annual pruning to get rid of the wimpy canes and attempt to space the bearing canes somewhat so that they have room to breathe. They should get direct sunshine and air circulation to stay somewhat free of diseases. That is what I do to the patch I have growing in my backyard. Monitor what you have growing to be sure nothing is encroaching on the new canes, and take action if any insect or disease problem is discovered.

Q: We have several dogwoods in our backyard that are doing well. They are sprayed for fungus problems and get water and fertilizer. While picking up sticks, I noticed one tree has a substantial amount of its bark chewed away near the bottom of the tree. This happened within the last few weeks. The tree shows no sign of damage as the turgor pressure of the leaves seems equivalent to those of the dogwoods nearby. What would you suggest be done to protect this tree from future fungal infection, drying out or attack by animals? Do I need to wrap the damaged area to prevent the additional loss of bark? Any additional thoughts or suggestions that you might offer would be greatly appreciated. Thank you for your assistance. (email reference)

A: A rabbit or vole has discovered your dogwood to be quite tasty. If the tree still is vigorous, that is an indication that no serious damage has been done. Get some rabbit or deer repellant, such as Hinder or Plantskydd, to spray on the trunk of the tree. Place a protective collar around the tree. This could be chicken wire or plastic tubing. If the tree is small, plastic irritation pipe might do the trick. A larger tree might be better off with an encirclement of chicken or rabbit wire above where the damage is evident. Do not attempt to paint the wound with anything. Check to see if there is any loose bark. If there is, use a pocketknife to cut it back to where the bark is attached to the trunk. It sounds like you have a vigorous dogwood that should recover nicely from this random vandalizing by some disrespectful rodents.

Q: We just started a strawberry patch with 12 plants. We put landscape material around the plants and then covered the area (including the plants) with straw to help keep the weeds away. Is that OK to do the first year? I know they have to be able to vine out and start new plants, but we aren’t sure if it is safe to leave the material and straw on the plants right now. (email reference)

A: I don’t recommend it. You might be smothering the young plants with too much of a good thing. I’d leave the soil uncovered to allow the plants to spread and root easily. You want the runners to root in the soil, not in the landscape mulch and straw. Also, just about every straw mulch I have seen comes with its own weed seed population that can create a problem.

Q: We have had a Deborah maple for around 10 years. It was just getting to be the perfect shade tree. Last year, the leaves never grew as large as normal and some of them didn’t turn from red to green. In the fall, most of the leaves stayed on the tree. This spring, the tree never budded out. The old leaves are still there. They are dark maroon and brittle. They fall off easily if you pick them. Some of the branches are dead, but some still seem to have life. Is there hope? I really love that tree. (email reference)

A: Based on what you have told me, it doesn’t sound like there is much hope for this tree. It sounds like it is a root rot or vascular (Verticillium wilt?) disease of some sort that is killing or has killed your tree.

Q: We moved to a home that is about 12 to 14 years old and has a lovely white birch outside the bedroom and bathroom. At night, it is spotlighted by lights that come on automatically. It gives us a view that we love. We surely do not want to lose our tree. I read with interest you material on birch trees. Because our problem seems to be fairly new and a regional one, our problem is not in your material. Our problem is the Japanese beetles that started invading the Midwest a few summers ago. They now come back in hordes every July. They feast on our roses, fruit trees, purple-leaf sand cherries and our treasured white birch tree. We have been spraying and setting out traps. They are helpful to some degree but do not seem to be sufficient for the birch tree. The spray is washed off whenever we have a good rain shower and the spray only reaches the lower part of the tree. Visible damage to the leaves on the upper part of the tree is apparent. I read that these beetles return to the same trees year after year, so some trees will not survive the onslaught. Is there anything we can do to save our tree? Thank you so much for any help you can provide. (email reference)

A: Spraying hordes of Japanese beetles is a losing battle because they will keep coming back. Set out pheromone traps or one-way traps in several locations around your property. The pheromone traps will fool the males into thinking there is a female inside to mate. Get a systemic insecticide, such as Bayer Advanced Tree and Shrub, and apply it early next spring just before the leaves begin to come out. Be sure to follow label directions. The material goes through the vascular system, so when the beetles begin feeding, it will kill them eventually. Keep in mind that the female lays eggs in the soil around these host plants, so treating the soil with grub insecticide also will help keep them under control.

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

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-7971,
Editor:Rich Mattern, (701) 231-6136,
Prairie Fare: Prairie Fare: De-stress with Gardening  (2019-05-23)  According to researchers, gardening can be beneficial for mental, physical and social health.  FULL STORY
Use of Releases
The news media and others may use these news releases in their entirety. If the articles are edited, the sources and NDSU must be given credit.

Powered by Plone, the Open Source Content Management System