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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I have a tomato problem. We planted our tomatoes this year in large pots. We have three plants growing in each pot. They are now producing green tomatoes, but in one of the pots, the tomatoes are turning brown on the bottom. We have cages around them so the tomatoes are not close to the soil. I can't remember the variety, but they will be about the size of cherry tomatoes. (Fargo, N.D.)

A: This is an annual question. The problem is more common on early-setting tomatoes and cherry-type varieties. This is called blossom end rot. The primary cause is too much water all at once and not enough calcium reaching the last cells being made on the tomato fruit at that time. After the cell breakdown takes place, then secondary rot organisms move to give the tomatoes a look that appears to be a fruit disease. In reality, it is a biological mechanical breakdown. No sprays are needed. If the rot has not progressed too far, you can cut that end off and eat the tomato without a change in flavor. You also can harvest the affected tomatoes and throw them away. In the meantime, try to maintain a consistent soil moisture level to keep the plants from going through wide swings of dry and wet cycles. We cannot help what Mother Nature does, but we can control our watering habits.

Q: We have two Marshall ash trees planted in the grass between the sidewalk and the street. Previous to this year, the trees have been strong and beautiful. Only the north sides of the trees have leaves this year. The south side is producing suckers. However, the nonleafed branches feel flexible. It has been a cold and wet summer so far. Could there be a need to cut the trees down? Can we encourage the strongest suckers to grow as replacements? (Dillon, Mont.)

A: The fact that suckers are coming up is an indication that these trees likely are doomed and should be removed. As to saving the strong suckers, that might sound like a good idea if you are willing to accept whatever these trees turn out to be. I am assuming that these trees are some sort of grafted clone. If so, the trees will be ash trees regrowing from the rootstock but will not be the same cloned material. It will be whatever was used as the rootstock. Even if it turns out that this sucker growth is acceptable, there is no guarantee that in another five years the same thing won't happen again.

Q: We planted broccoli and peas in our garden. Something was eating the tops off the peas and the leaves on the broccoli. We sprinkled slug powder on the ground around the broccoli plants, but there still seems to be something eating the plants. Could you please help us figure this out? (e-mail reference)

A: My first suspicion is the bunny population. One cute little nibbler can destroy a garden crop in a matter of minutes. Rabbits would be indifferent to the slug control. I suggest a physical barrier, such as chicken wire fencing, that is securely attached to the ground using stakes.

Q: Some of my petunia blooms have been doing a strange thing. The bloom develops and looks as if it is going to open, but instead it doesn't open and the ends curl inward. Also, some of the blooms have lost their color as if they have been touched with bleach. Do you know why this is happening and can you tell me what to do about it? (e-mail reference)

A: The bloom not opening is usually evidence of thrips feeding just under the flower petals before they open. As blooms age, their colors fade, so pick them off (called deadheading) to keep fresh blooms growing.

Q: We have two raspberry plants in their second year of harvest. One plant is doing very well. It has many new canes and is bearing delicious fruit. The other plant started well and was fruiting, but the leaves started to yellow and the entire plant is starting to dry up and die (leaves, fruit and cane). This also is starting to happen to the other canes of the same plant. (e-mail reference)

A: I can't tell you for sure what would be causing this, but I advise you to dig up the affected plant and dispose of it as soon as possible. This sounds like a verticillium wilt problem. If so, there is nothing that can be done.

Q: When is the best time of year to transplant wild raspberry bushes? (e-mail reference)

A: When they are dormant in early spring or late fall.

Q: Recently had a lady ask me what is wrong with her spruce. All the growing tips are turning brown. I noticed she just had an exposed aggregate driveway installed. Could the problem stem from the harsh, salty chemical? Is there a remedy? Only the emerging candles seem to be affected. (Washington state)

A: That absolutely could be the problem! Those aggregate surfaces include deadly esters that could cause damage to the tender, emerging tissue. I'm not going to say it will not hurt the mature growth, but chances are it will not unless some of the chemical was dumped directly onto the roots. Since this is in rainy Washington, I would suspect that the chemicals should be leached beyond the root zones or diluted sufficiently enough that the trees will not be harmed permanently.

Q: What is your opinion on using Epsom salt as a fungicide? What about baking soda? Is baking soda legally labeled for fungicide use? (e-mail reference)

A: Baking soda often is recommended to control powdery mildew by popular garden writers. Research has shown that baking soda is no more effective at controlling this or any other disease than a spray of clear water. People are taking chances when they mess with stuff like this because people typically do not measure carefully enough, so overdosing is common. The result is fried foliage. The same is true for those using Epsom salt. Sure, the sulfur within has some fungicidal properties, but so does continuously running water. Use Epsom salt for what it is good for, which is boosting magnesium in deficient soils to get a good, quick reaction. Most of these things get good press because they break away from conventional practices. Keep in mind that most conventional practices are based on science, not hopes, wishes, prayers or one's imagination.

Q: Our long-established lawn is infested with night crawlers. Since they move so much soil to the surface as castings and make our lawn so rough, do we still need to consider aerating our lawn to get the grass to fill in to become a turf that will choke out dandelions, clover, chamomile and plantain? Much of the lawn gets extensive shade due to some large elm trees and a weeping birch. We fertilize twice a year. (Grand Forks, N.D.)

A: The activity of night crawlers is sufficient to get the lawn enough air. What I would encourage you to do is consider rolling the lawn with a ballast roller after a decent rain so the soil is soft. You also should consider overseeding with an aggressive cultivar of creeping red fescue, such as Navigator, that is shade tolerant and will give you a nice, thick lawn with two fertilizations a year.

Q: I have night crawlers in my lawn. How do I get rid of them? Many years ago, we owned a different place and I used a mixture of Malathion. I put it on the lawn after an early evening rain. What would you suggest? We have a fairly large lawn. (e-mail reference)

A: Malathion will kill just about any animal it comes into contact with. Being an oil-based insecticide, you probably caught most of the night crawlers that migrated out of the soil or were in the upper part of the lawn when you made the application. Malathion is a neurotoxic insecticide that is absorbed through the mucus membranes of insects and is soluble in water. Hence, a very good kill. Unfortunately, it also kills beneficial animals, which may or may not be a concern to you. You almost can achieve the same effect using a lawn grub insecticide. While not targeted for night crawlers, it kills about one-third of the population. Another approach I like to recommend before going to the toxins is to power rake the lawn aggressively to break up the mounds. After that, pick everything up with a sweeper or lawn vacuum (or even a powerful rotary mower with the bagger attached) and then go over the entire area with a ballast roller. While the kill is smaller than using insecticides, it doesn't harm nontargeted organisms in your yard. Some people employ a combination of this with an annual application of grub insecticide, such as Scotts Grubex or a similar product, early in the spring.

Q: I have five blue spruce trees in my yard. One of the trees is showing signs of browning at the upper part of the tree. The remainder of the tree has the green-bluish hue. I also noticed what appear to be bagworms all over the tree, not just the top portion. I quickly sprayed Sevin on the tree in my haste to do something. Afterwards, I had my doubts if this was such a good idea. Can you recommend a treatment or is it too late? Also, should I attempt to manually pull off the bagworms or is a chemical treatment the way to go? I am assuming there isn’t another pest or disease that is causing the browning. (e-mail reference)

A: Manual removal is best because this is a difficult pest to control with topical sprays such as Sevin. To prevent damage in the future, I would suggest an application of a systemic insecticide that contains the active ingredient Imidacloprid. It might not be as effective if applied at this time of year because there isn’t much new growth at this time. I am assuming new growth has emerged and hardened off by now. If you can get the bagworms removed by hand for now, I would suggest applying the material early next spring after the frost is out of the soil. That should give you seasonlong protection from any plant munchers until the following spring.

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