May 30, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I am sending you a branch from the top of one of our spruce trees, which is getting more brown by the day and spreading downward. The trees near this one are okay so far. What could be causing the problem? Can we arrest it in time to save the tree, and what about the contagion possibility to the nearby trees?

A: There was no evidence of a pathogen or insect damage on the sample you sent. It is evident the tree is under stress of some kind in its environment: salts accumulating in the rootzone, compaction, planted too deep, over-zealous cultivation, drought/heat, insufficient water, or any combination of the above. I suggest making sure the plants have sufficient moisture throughout the growing season, that they are protected from salt spray, and that they are not planted too deep or kept too wet. I know this is not a "nailed-down" answer for you, but lacking any pest evidence, we have to examine the growing conditions.

Q: Have you ever seen the Christmas rose (helleborus niger buis) growing in this area? I planted one last year and it didn't survive. It is supposed to be hardy in zone 3. What kind of soil do they prefer? (E-mail reference)

A: Actually, hardy to zone 4, but this past winter shouldn't have killed it. They don't like hot soil. The prefer cool, moist, and high in organic content soil that is also well-drained. Kind of a hard combination to come up with in the Red River Valley soil!

Q: We have a giant snowball bush that we would like to prune into something more manageable. I have read that we should do this pruning after the first hard frost of fall, but have also read to do it immediately after the flowers are finished blooming, which is early summer. I did some pruning a couple of years ago in the early summer and wherever I pruned it appears those stalks are now dead (no foliage at all!). Am I slowly killing this plant? Is it worth saving when it is very, very woody? Also, I have a lilac bush which I inherited from my sister-in-law's back yard via pulling up some roots. It is a beautiful bush (now about 3 feet tall) but only produces foliage, no flowers. Is there something I can do? It is in full sun with good drainage. (E-mail reference)

A: It all depends on what you are calling a giant snowball bush; there are at least three species that I know of that are often referred to as a "snowball"; Viburnum, Hydrangea, and Ceanothus. As a generalization, the best time to prune is right after flowering, if the subsequent fruit is not important. When pruning, it is also generally a good idea to remove the cane completely, right down to the base of the plant, assuming the proper pruning techniques are followed. With the lilac, I simply suggest patience. You may be too good to it, providing too much fertilizer. Generally they do get around to producing flowers. Just don't do any late summer pruning.

Q: I enjoy listening to you on "Hear It Now" and have a question. Our front lawn in Minot needs to be re-done. Is it possible to have a lawn without too many weeds without using 2,4-D all the time? We don't like to use many chemicals and poisons, and I'm wondering what to ask for when we hire someone to redo our lawn. Is it important to have a deep layer of topsoil before we do the seeding or sodding? ( Minot, N.D.)

A: Thanks for being a fan of North Dakota Public Radio and "Hear It Now." The SOP (standard operating procedure) for lawn renovation is to kill everything off with Roundup, which is about the most innocuous herbicide that can be used for that purpose. Then, scalp-mow and collect the clippings, core aerate, power rake, fertilize and seed. Water until everything germinates, mowing what comes up in the meantime to about 2.5 to 3.0 inches. Take care to mow high and fertilize regularly after that, returning the clippings to the lawn each time, and you should have a relatively weed-free lawn without the use of herbicides.

Q: Approximately two years ago we removed a large diseased maple tree from our front yard. Since that time we have had an abundant crop of mushrooms. We have been unable to keep them under control and would welcome any suggestions that you may have. They are affecting the lawn. (Jamestown, N.D.)

A: The presence of mushrooms indicates that nature is working to digest the stump and remaining root system. If this is not acceptable to you, the only alternative I am aware of is to have a tree/stump removal company come in and grind everything down to sawdust and haul it away.

Q: I had a few questions about planting some Colorado blue spruce evergreens. I was planning on ordering the 5-year-old transplants out of Pennsylvania. I was just wondering how late I could plant the trees, and how well they would grow in North Dakota after being raised in Pennsylvania. Also I was wondering how late the growing season lasts. (Jamestown, N.D.)

A: If they are containerized or balled and burlaped, anytime the soil isn't frozen; otherwise you are too late for this year. I would also suggest that you look locally, within our region, as the stock would likely be from some of our hardy specimens and would be sure to survive our weather conditions better.

Q: I have a crabapple tree that has a ton of fruit on it. The problem is we don't use the fruit. Is there a spray that you can use to keep the tree from bearing fruit? If not, is there any other method short of cutting it down, which is what we will have to do if there is nothing we can do to control it. (Grafton, N.D.)

A: There are sprays, but they are not dependable. I have a Dolgo crabapple that bears way more fruit than we can ever get to, creating a mess that I have grown to hate cleaning up in the fall. My solution is going to be to cut it down after flowering this year and replace it with something that is not as messy.

Q: I'm never sure what annuals should be deadheaded. I know petunias should be. What about million Bells, stock, geraniums? (E-mail reference)

A: Right now, I cannot think of any that wouldn't benefit from being deadheaded (removing the flowers by pinching back). Certainly something like Alyssum wouldn't be, or any other plant with a similar flower structure.

Q: Why doesn't our Dropmore honeysuckle bloom? (Fargo, N.D.)

A: Might be not enough light or too much fertilizer that is high in nitrogen.

Q: I don't know what the stuff is called that drops from trees as they are leafing out. That stuff remained on a new planting around a farmstead. The trees are dead this year. They are 3 years old. Is there a disease affecting the tree and would it be causing death? (Ellendale, N.D.)

A: That is probably the leaf coverings or flower (bud scales) parts that are dropping off. This is common on poplar species, ash species, etc. and is not a source of problems or disease.

Q: I have some 7-foot Colorado blue spruces that have developed needle cast disease. I just applied Daconil 2787. In the meantime I have planted more Colorado blue spruces 7 feet tall and some Norway spruce 5 feet tall. Would it be safe to spray Daconil 2787 on the newly planted trees? (E-mail reference)

A: Yes, in June and again in July, until the symptoms on the affected trees are gone.

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