« Continue Browsing

e-mail article Print     e-mail article E-mail

Don Kinzler, Published April 06 2012

Hortiscope: Roses should recover from pruning mishap

Q: I hired my neighbor’s son to prune my roses. He cut them down to about 12 inches from the ground instead of the branch line. How can I save my beautiful roses? Will the roses grow if I give them fertilizer and water? I live in the South, so I do not have to worry about freezing. I am scared I have lost all of them and all of my hard work. (email)

A: You should have nothing to worry about. Roses bloom on the current season’s growth, so yours should break dormancy and send up new shoots when the temperatures are right. At that time, you can shape the plants the way you wish as they grow and produce flowers.

Q: We planted four chokecherry trees five years ago. They have not grown much (currently at 18 feet) but appear to be healthy. What is causing their lack of growth? They were sold to us as trees. Could they be a bush chokecherry variety?

Even if they are a bush variety, they should grow. I’m tempted to just get rid of them. I used fertilizer pegs on them and they got slightly bushier, but there was no height gain. You were recommended as the guy who can help us. (Spearfish, S.D.)

A: Chokecherry trees are gauged to get 20 to 30 feet tall. It depends on their environmental setting. It would not be a statistical error for yours to more or less top out at the height you mentioned. Some continued growth in height can be expected, but they have pretty much reached what they are genetically programmed to do. Progress from here will be slow.

If you are not pleased with the situation, I would remove the trees and replace them with something that will get to the height you want. Go to http://bit.ly/HGMHZm and then click on the table of contents. In the table of contents, click on chokecherry to get a full description and photos of mature chokecherries. You can see there that the largest tree in North Dakota is 41 feet tall.

You also can peruse the handbook for trees you might want to use as replacements. Don’t waste your money on the fertilizer spikes because they are not worth it. To fertilize, spread a complete fertilizer, such as a 10-10-10 or something similar, from the edge of the tree canopy out as far as you reasonably can go.

That will do a much better job of getting the fertilizer where it can do some good.

Q: I bought and planted two chokecherry trees in 2006 and two more in 2007. They are now equal in size at 2 feet. We have clay loam soil. The trees were planted in an alfalfa field (future home site). At times, we get very hot temperatures, but the plants never see any water except from Mother Nature.

I have planted many ponderosa, some burr oak and Austrian pines successfully. My cottonwood plantings failed due to a lack of moisture. Is it possible they are not growing because of the conditions or could they be bushes instead of trees? Is there anything I can do to spur growth? I appreciate your help. (Whitewood, S.D.)

A: If the other species you mentioned have grown satisfactorily, the environment should be conducive enough for chokecherries to grow to a decent size.

I would suggest that you contact John Ball, urban forester at South Dakota State University, so you can send him a sample of your plants to get a positive identification. To make it a little easier to identify if they are chokecherry trees, wait until they have fully leafed out. Ball can be reached at john.ball@sdsu.edu.

The Prunus species all look similar to each other. It takes a keen eye to distinguish the differences. Chokecherries are remarkably adaptable to all kinds of soil and environmental conditions.

Your site shouldn’t have that much of a dwarfing effect on growth. I suspect that it must be one of the many shrub cherries that you were given mistakenly.

Q: I have a volunteer fir tree that I would like to move. It has a wispy Charlie Brown Christmas tree charm about it.

I started to do some investigative digging and found a couple of substantial roots from the big cedar.

I’m concerned that if I do what I have to do to create a viable rootball for the volunteer, I will risk the health of the big cedar, especially if we have a lot of dry, hot weather.

Is it safe to cut through those roots to extract the rootball for the volunteer? (email)

A: Anytime roots are severed, it increases the chance of the tree falling over during high winds. However, Mother Nature usually plans for such problems.

Hearing what you have told me, and if you go about the task with due diligence, you should be able to extract this Charlie Brown volunteer from a site where it has no chance to thrive and move it to a place where it has a better chance to live. In essence, I think you are safe to carry out the operation.

Q: How do I get rid of crown vetch? Will rototilling the area kill it? (email)

A: It will disrupt it somewhat, but being a deep and tough-root perennial, I would bet that you will get regrowth very soon.

I would suggest using a systemic herbicide, such as Roundup, at the maximum concentration to do the job. Allow it to turn green this spring and give it a good covering spray. Mow the area after 10 days or when visible evidence shows most of it is dead.

Respray any that escaped the initial dose and then wait another 10 days to be sure it is killed completely. After that, rototill everything if the second treatment did the job.

Keep a spray bottle on hand for any stubborn sprouts that may show up.

Q: I would like to establish some native species in beds on our farm. Some of these plants have tap roots that are very difficult to transplant. Is there a propagation method you would suggest?

I live in central South Dakota and would get the plant material from my own land. (email)

A: Collect seeds and mix them with sand before scattering them or dig and move the seedlings before the tap roots become too extensive.

With perennials, try to take fleshy cuttings after they have flowered and root them in a sand/peat mix.

Transplant them when the roots are established enough to support the plant on its own.

Q: I found your website, where you answered a variety of questions about spruce trees. I ended up planting four blue spruce trees two years ago. Until recently, everything looked good. I’ve attached two pictures of the trees planted about 15 feet from each other.

The tree starting to turn brown just showed signs of a problem in the last two months. This tree hasn’t grown as fast as the other three trees but has stayed green up to this point.

I used spikes last fall on each tree but do not water them regularly. I live in Minneapolis. If you have any suggestions on how to fix the problem, I would appreciate it. (email)

A: The dead-looking spruce likely is not going to recover. I have no idea what killed it, because that is something only a lab diagnosis can determine.

My strongest suggestion is to not waste your money on fertilizer spikes because they are ineffective and expensive. Fertilizer spikes bring on lots of frustration to the homeowner who uses them.

Q: Last spring, I planted some dwarf Norway spruce shrubs. I followed all the rules.

This spring, all of the plants have dropped the majority of their green needles. I see there are buds at the tips. If I break off a twig, it is green inside.

Will these plants survive or should I start over? What caused this? I hate to kill plants. Thank you. (email)

A: I have no idea what would have caused this to happen. The likelihood of the shrubs recovering into anything decent is very remote.

You need to contact a horticulturist in the Colorado Extension Service. Go to http://bit.ly/H65b7O and click on your county to get in touch with an agent who should be able to guide you in determining what went wrong and how to keep it from happening again.

Q: Would now be a good time for seeding a lawn? I always figure the sooner the better. However, the way this year is going has me scratching my head! (email)

A: As long as the frost is out of the ground and the soil surface is not too wet, go ahead and seed. Moist soil is OK, but saturated soil is not.

Even if the temperatures dip again, it won’t hurt anything because the seed will be going through a priming process while it is sitting there waiting to germinate.

Q: Is it all right to thatch the lawn here in Dickey County or is it too early?

I understand the grass is starting to grow. (email)

A: As long as the grass is starting to grow and the surface isn’t too wet, dethatching can begin. Be sure to follow up with an overseeding of a Kentucky bluegrass mix.

Q: I have planted some emeralds 5 feet from a fence. I left 6 feet between each plant. Is this too much space? (email)

A: The emeralds will fill in eventually. In the meantime, you can plant some shrubs between them to close up the gaps.


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 email ronald.smith@ndsu.edu.