June 6, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I came across your website in my search for what I thought would be a common and easily resolved problem with my 9-year-old maple. The bark has milky white patches all over. The patches vary in size but range from 2 to 7 or 8 square inches. The aesthetics are not bothersome, but the tree is about two weeks behind in leafing out. It is budding, but seems sparse. Any idea? (Stillwater, Minn.)

A: Trees everywhere in the upper Midwest are behind. The milky white patches concern me a little. It is probably a Norway maple, and could be troubled by borers (not likely) or by sapsuckers. The sapsuckers punch holes in the trunks of various trees, and the milky exudate you are seeing is simply the sap and usually causes no harm. The tree will heal naturally. Just be patient with the leafing out this year.

Q: I've inherited a boston fern from my sister-in-law who recently passed away.

She had it in a basket causing it to have approximately 9 inches of dried stem before the fronds grew. I would like to transplant this or whatever I need to have a healthy plant, but do not know where to start. It has sentimental value for me and I would like to do what I can to revitalize it. Could you give me advise on what to do? (E-mail reference)

A: No problem. Ferns need a high humus mixture in a container that will facilitate good drainage. It should also consist of about 60 percent peat-based potting mixture and about 40 percent coarse sand or medium grade perlite. Some recommendations call for the addition of one cup of activated charcoal. Work into this mixture a low analysis fertilizer that is recommended for ferns (10-10-10) or something similar, and keep well watered.

Q: I got a spider plant for Mother's Day and have noticed that the ends are turning brown. Do I cut them off or pull them off? (E-mail reference)

A: You can do nothing, and the plant will be all right. The brown tips are a reaction to the chlorine or fluoride in the water or as a part of the soil mix; or simply a salt burn from the soluble salts in your water supply. My spider plants have had brown tips for the past 15 years and are still producing an abundance of "baby spiders." My suggestion: learn to appreciate the brown tips as part of the ornamental attraction of the plant. It will not be lethal to the plant.

Q: Please help, I bought some petunias from a garden center about eight weeks ago, put them into hanging baskets, and they were doing really well. Suddenly, the leaves have gone brown, and the flowers are all very damp and not opening. I have watered them lots, then left it thinking maybe I have watered them too much, but they are still the same. They are in the sun for about six to eight hours when it is sunny, but lately we have had very windy and rainy weather. Is there anything I can do to save them? (E-mail reference)

A: It sounds like they might have been hit by a frost. Dump them and begin again.

Q: I cut the edges with the brown spots on the spider plant off. Will that harm the plant and if so is there anything I can do to help save it? (E-mail reference)

A: No problem - the brown will likely return to the edges you just created. Just ignore them in the future.

Q: How far apart should I plant blue spruce? (E-mail reference)

A: Fifteen to 20 feet apart.

Q: The leaves on my ash trees froze. Will they come back yet this year? ( Linton, N.D.)

A: If they truly froze, they are gone for the season, but Mother Nature is clever. She doesn't expose all of her leaves at the same time to the vagaries of the weather in North Dakota, so a second flush should be taking place in two to three weeks from the buds that did not open early.

Q: I looked at an apple tree with a sooty black material on the top side. It rubs off but a little dark color stayed on the branch. The branch is about 1 1/2 in diameter, soot starts about 2 feet out on the branch-then goes for about 18 inches. Total branch length 7 feet. There are millers, millers everywhere. How do we get rid of them? (Harvey, N.D.)

A: The material on the apple branches is sooty mold, a saprophyte that lives on the surface of the branches and does not become directly parasitic. Left unchecked, it can interfere with the photosynthetic activity of the tree in some cases, weakening it to attack by parasitic organisms. It is easily controlled with insecticidal soap. Those millers or moths could be codling moths, among many other species. They are very vulnerable to pheromone traps, sticky traps, and to natural predators. The resulting larvae can be controlled with Bt applications, which is not toxic to the environment or non- destructive species.

Q: After spending a lot of time last year looking up blossom end rot and finding that it means we need to add lime to the soil. I looked and looked and could not find lime for the garden. I finally did plant two plants and added plenty of the so called tomato plant food, thinking that just might take care if the problem. Well we got about four tomatoes that did not have the blossom-end rot. This year I have looked and asked about lime and all I can find is lime for pickling. Now I wonder if this would work and if so how much to put in the area for the tomatoes. I have a planter box that will hold two plants. If this will work and you can tell me about how much to use I sure would appreciate it. I am wondering why it is not available and more people do not use it as I hear so many talk about the bad tomatoes that they grow. (Forman, N.D.)

A: Blossom end rot is the result of calcium failing to reach the ends of the tomatoes during initial cell formation. It is caused by water availability fluctuations (dry then wet), damage to the roots that causes them to have limited ability to absorb calcium and, believe it or not, cultivar characteristics. Some are more vulnerable to it than others. I would forget about adding lime. Our soil is plenty high in calcium. Try to plant the tomatoes when the soil is warmed enough, plant them deep, mulch with peat moss, water evenly and try not to get too close to the roots when cultivating around the plants. Also, it is usually only the earliest tomatoes that are most subject to BLR. Try my suggestions and let me know how everything turns out.

Q: A client brought a small branch from his chokecherry tree. It has a black growth about 5 inches from the tip. It kills the trees and gets worse every year. What is it? (Linton, N.D.)

A: That is a fungus known as black knot. He needs to prune out any branches that have that growth on them. Spray lime sulfur on the trees while they are dormant in the spring, followed by a product called Caviler (thiophanate-methyl) at the pink bud stage, full bloom and three weeks after full bloom. If the disease has badly crippled the tree, the client is better off removing it.

Q: We are learning about grasshoppers. Could you answer some questions?

1. How can grasshoppers eggs stay alive during the winter?
2. In a book we read grasshoppers got in the water and it changed colors.
3. Where do grasshoppers go during the winter?

Thank you. (E-mail reference)

A: Glad to help -

1. Grasshopper eggs stay alive during the winter because they are in a stage of very deep inactivity, so they are not vulnerable (can't be hurt) by the cold temperatures.
2. The grasshopper body fluids are green, while ours is red. When they have their skin broken or cut, they "bleed green" while we would bleed red.
3. The cold weather kills them off if you are talking about North Dakota. If you are from a mild climate, they might find some place warm enough to allow them to survive.

I hope this answers your questions.

Q: Hope you can help. I have put in some native plum and apple but the tubex is significantly longer than the bare root stock. Should I cut them back to the length of the tree or leave them? (Sheyenne, N.D.)

A: Cut them back to the length of the tree.

Q: I have a number of lilac bushes on my property that are growing out of control. I trim them back every year, but they seem to grow back like wild fire. Do you have any advice on how to remove lilac bushes and how to keep them from coming back? (E-mail reference)

A: Treat them like weeds and spray with a systemic herbicide (like Trimec) as they resprout. It may take several applications but you will eventually win the war, and it is a lot easier than trying to dig out each and every sprout that comes up.

Q: I have a ton of little oak trees sprouting in my grass. They are all caused by the acorns that fell last year that were not raked up. Is there anything I can do to kill off these seedlings without killing my grass? (E-mail reference)

A: Treat them like weeds with an application of a broad-leafed herbicide. It will not hurt the grass and will kill the seedlings. Of course, regular mowing will do the trick as well. I have never known oak seedlings that will survive mowing.

Q: I bought a lilac bush last year that is an all summer bloomer. It died over the winter and we want to replace it and can’t remember the name. We can't seem to find one that blooms all summer like that one did. Can you help with the name? (E-mail reference)

A: The 'Miss Kim', 'Tinkerbell', and the Dwarf Korean lilacs are the only ones that I know of that may have a repeat bloom during the summer. None flower continuously all summer.

Q: My husband wants to transplant a lilac bush from one piece of property to another. The bush was started about seven years ago from a twig that was transplanted. Now the bush is about 3-1/2 to 4 feet tall and is blooming for the first time this year. When is the best time to transplant this bush, with the least amount of trauma to the bush? (Beach, N.D.)

A: Next spring before the plants leaf out.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu