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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: My hibiscus is so pretty, but the blooms only last about a day. Is there something I can do to make the blooms stay on longer or is that just their nature? (e-mail reference)

A: That is pretty much their nature.

Q: I hope this is the proper channel for plant questions. I have tiny, red and yellow bugs (I'm guessing aphids) covering my potted petunias. The flowers have stopped blooming and the leaves are full of holes. What, if anything, can I do at this point? The bugs are quite large in quantity! (e-mail reference)

A: Spray the plants with any number of insecticides on the market. Ortho has a line of insecticides that would be effective, as do many other companies. Spray the plants right away before the bugs destroy the plants. There is still time for them to recover and give you a good blooming cycle.

Q: I planted two autumn blaze maples in my yard in south Fargo last year. This year, the leaves started to turn red about the middle of June. What could cause this problem? I have been told they may have gotten too wet from all the rain during that time. The soil was gray clay, so I added some peat moss as suggested by the nursery. Any ideas or suggestions would be greatly appreciated. (e-mail reference)

A: Check to be sure that the tree has not been planted too deeply. The top of the rootball should be even with the surrounding soil. If it is deeper, pull some of the soil back until the top is visible. Use light bark mulch to fill in the area, but do not put the mulch against the trunk. Hang in there because the tree may recover with the warmer and drier weather cycle we are in.

Q: I hope you can help me. My spider plant has long stems and is very healthy, except for the little brown spots on the stem and the underside of some leaves. There also is a sticky substance being excreted from the stems or leaves. I have moved it away from the other houseplants. What can I do and what is the problem? (e-mail reference)

A: It sounds like some scales have taken up residence in the plant. To control these tough pests, you need to use a systemic houseplant insecticide, such as Dexol Systemic Insecticide or Rigo Systemic Insecticide Granules. Either of these products or others like it should be available in most major retail outlets that market garden products and houseplants.

Q: I have a very dear azalea that I received as a gift almost 11 years ago. However, the azalea has started to drop its leaves without any indication as to insects or problems I know about. The dropped leaves are green and do not appear to have problems. Since I care about this azalea so much, I tend to watch it closely. Any ideas on why the leaves are dropping? (e-mail reference)

A: The plant must have been stressed in some way. It could be a break in the watering regime, excessive heat, a hot or cold draft or something else. Have you recently moved it? Has it been in anyone else's care? Have you hosted a party where someone might have poured a mixed drink into the pot? Check the cambial tissue beneath the bark. If it is still green, then it should come back. If not, then whatever happened to the plant is lethal. You established a good track record by keeping it alive for 11 years, so it is likely to recover once you determine what caused the leaf drop.

Q: I have an autumn purple ash that has hard, brown things on the branches that stayed on the tree all winter. The tree was planted 13 years ago and developed these things two years ago. I was looking at the tree closely because emerald ash borer was discovered in my county. However, I saw no zigzag larvae patterns, but I did see several small, round holes in the bark about 1/8 inch in diameter. Is the tree OK? The foliage looks fine. (e-mail reference)

A: The holes in the bark the size you describe probably are from sapsucker activity, especially if they follow a pattern going around the trunk. The grape-sized knots you see on the tree could be galls that are not destructive. If you have concerns about the tree, I suggest contacting an International Society of Arboriculture certified arborist. Find one in your region by going to

Q: About a month ago, I planted four Japanese spireas on the south side of my house, which gives them full exposure to the sun. However, one of them definitely has a sickly look to it. Some browning of the leaves is occurring (I've attached some pictures). I don't believe that the purple leaves are a concern. Other spirea shrubs also have purple leaves at times. I don't believe there are any problems with insects, at least not visibly. However, I am concerned about the disease and the potential to have to dig up the plant and destroy it. Are there any cures or applications you could recommend? (e-mail reference)

A: The symptoms indicate a problem in the root zone. Your problem could be overwatering or the soil staying saturated too long, compaction of the soil, plastic covering the soil causing anaerobic conditions, heavy fertilization, salt accumulation or the spirea is planted too deeply. If the site where they are planted is not well drained, that could be the problem. You are better off digging the plant up and building a raised bed or planting somewhere else.

Q: There is something making some awful noise in the trees of my yard. It's kind of a humming, vibrating noise. The noise almost sounds like a cricket chirping, but 10 times louder. Do you have any idea what it is? I went over to the trees, but cannot see anything. The noise will all of a sudden stop, only to start again in another part of the yard. I've never heard anything like it before. (e-mail reference)

A: The noise you are hearing is very likely that of the cicada. They are huge, ugly (some would say) insects that move slowly and eat a lot of landscape foliage. The female lays her eggs through slits she makes with her sharp tail in the trunks of trees. Cicadas favor young fruit trees. Depending on where you live, their life cycle should be coming to an end shortly. Then 17 years from now, you just might hear the same noises again! University of Illinois entomologists estimate that the outbreak will number more than 5 billion this year in that state alone!

Q: I just moved into my new home in January. I have been told that the tree growing in my front yard is an ornamental flowering plum tree. It is bearing a plentiful supply of small fruit. Is the fruit edible and usable in recipes or should they be removed and destroyed? (e-mail reference)

A: The fruit is edible for humans, birds and squirrels, so enjoy!

Q: We have webs showing up on the surface of the lawn. The webs show up when the lawn has dew on it. Is this anything to be concerned about? (Minot, N.D.)

A: Fungal development, such as dollar spot and pythium blight, usually occurs when night temperatures are above 65 degrees and dew is on the leaf surface for extended periods of time. In most situations, the turfgrass will outgrow it or, in North Dakota, the weather will change, so the disease will not progress.

Q: I want to put rock and edging under my deck. I just want the rocks or some other type of mulch to look nice because grass won't grow under the deck. If you could provide me with any tips for removing the sod, that would be great. Is it easier to remove sod if I spray it with Roundup first or should I just remove it? Is a flat spade the best tool for removing the soil? Do drier conditions make it easier to remove? (Fargo, N.D.)

A: Save yourself time, money and effort by killing everything with Roundup. Mow the dead grass short and put the rock or other mulch on top of it. I suggest using organic material, such as bark nuggets, rather than rock, but that is a personal preference of mine.

Q: My son has planted pumpkin seeds for the past two years. We always get a lot of vines with male flowers, but no female flowers. Do you have any suggestions as to what we may be doing wrong? We live in Georgia. (e-mail reference)

A: You and your son are doing nothing wrong. It just happens to be the luck of the draw. Usually, plants will produce male and female flowers. If you made your seed purchase locally, they should be producing female flowers by now. If they were purchased by mail, there is a chance you got a cultivar that is specific to the northern region of the country, so the seeds may not develop female flowers.

NDSU Agriculture Communication

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