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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: Can one transplant rose bushes in the fall? I also would like to know if I should fertilize my trees this fall or wait for spring. (e-mail reference)

A: Transplant your rose bushes by this weekend. The bushes should be OK because the soil is still warm. If your trees are surrounded by turfgrass that receives regular fertilizing, you should not need any additional fertilizer. In most lawn situations, the fertilizer schedule calls for at least three and sometimes four applications. This will deliver more than enough nutrient content for satisfactory, healthy tree growth. If you must fertilize the trees based on visible evidence of reduced growth or lack of vigor overall, then apply the fertilizer in the spring once the soil is free of frost. Here is a site,,that explains the process more fully.

Q: I have a flowering pear tree that I purchased last spring. The flowers fell off, but the leaves were green all summer like all the other pear trees in the area. In mid-September, the leaves fell off and I thought the tree was dying because of the very dry spell we had. We watered the tree heavily, so now it is blooming with white flowers. It was warm for several days in a row. Why does this tree have flowers while the other pear trees in the area don’t? What should I do? I really would like to understand why it is flowering, but nobody seems to know. (Mullica Hill, N.J.)

A: There is a flowering hormone, but not specifically identified as of yet, that stimulates flowering after a certain set of criteria are met in the plant. This commonly is caused by cold temperatures or “chilling” to induce some trees to develop flower buds. Other plants need day length combined with heat to develop and set flower buds. Plants, like people, can have their hormones get out of whack due to stresses. For plants, excess heat, drought, physical wounds (abiotic) and biotic wounds from pathogens or insects can cause the hormone imbalance. Your tree may be a little more sensitive than the others in the area or has suffered some additional abuses that you don’t know about. There is nothing you can do about this phenomenon except keep your tree under observation. It will not produce flowers on those same branches next spring. However, the tree should get back into the swing of things in future years.

Q: I have a silver leaf maple tree. My 14-year-old son apparently thought it would be cute to remove the bark from the tree yesterday. The bark is completely stripped. Is my tree going to die? (e-mail reference)

A: It all depends on how complete a job your son did in removing the bark. If it is completely girdled, then it will die. There is nothing you can do about it. If there is a strip of bark running between the root system and crown to the branching area, then there is a chance the tree will recover. However, the tree will be weak and more vulnerable to other misgivings, such as diseases and insects. Your lad needs to take a botany or horticulture class to learn how important trees are to our environment and how important bark is to a tree.

Q: We have a 50-foot line of lilacs along a dirt road. The lilacs are 15 to 20 years old, but not very tall. Weeds are a real problem. I know that lilacs require a lot of water, but this is at a summer trailer park resort, so we are only there three days a week. Also, we do not want to put a lot of rock, chips or other material around the plants to help with the weeds because I feel this would inhibit the spread of the bushes. We need them to grow taller because the trailer is close to the road and the bushes are there to help with the dirt flying off the road when there is traffic. I know the quality of the dirt the bushes are planted in is not the best. Is there a way to encourage growth by adding something to the soil that would help hold moisture and nurture the bushes? What would you suggest? Also, is there a way of inhibiting weed growth? What about grass clippings? (e-mail reference)

A: Your wishes will be tough to accommodate! You are correct to not want to put fabric and stone over their roots. Grass clippings will control weeds somewhat, but be sure the clippings are not treated with a herbicide when you spread them. The clippings will control the weeds and have a negative impact on the growth of the lilacs as well. If you fertilize your lawn without herbicide applications, the grass will provide trace amounts of nutrients to the lilacs and encourage greater growth. It also will have a modest conditioning effect on the soil. The grass clippings will help increase the moisture in the root area of the lilacs. After the lilacs go dormant this fall and before they break buds next spring, try to clear out the weeds by hand. Then apply a pre-emergent herbicide known as Treflan (trifluralin). It will give you the best weed control without harming the lilacs.

Q: When my wife and I bought our house in 1998, we had an old crab apple tree in our front yard that produced gobs of crab apples. I suspect that the crab apple tree was planted when the house was built in 1964. After a couple of years of shoveling bushels of crab apples into garbage bags and throwing them out in the trash, I decided that it was a waste to throw them all away, so I started making wine out of them. They made excellent wine. I ground up the seeds with the apples, which gave the wine a pleasant nutty flavor. Unfortunately, several years ago, the invasive Chinese ladybugs (the ones that bite) appeared in our area and swarmed the crab apple tree along with fruit bees. After my wife was bitten several times by the ladybugs and stung by the bees, she made my dad and I cut down the tree. I have missed the wine I used to make, so I would like to plant another crab apple tree in my backyard. The old tree was planted too close to the driveway, so it used to drop lots of crab apples on the driveway. It was a big mess when cars drove over the fruit, and the mess attracted bees and ladybugs. From looking at pictures, I think the tree was a dolgo variety, but I am not sure. The fruit was red and shaped like a dolgo. Most of the fruit dropped from the tree when ripe, but some stayed on the tree until it rotted. Was our old tree a dolgo or are there other varieties similar to a dolgo that more accurately describe the characteristics of our old tree? (Joliet, Ill.)

A: Most likely it was a dolgo crab from your description. From personal experience, I agree it makes an excellent wine and applesauce. However, consider carefully before making a purchase. You will get more apples than you possibly can use and continue to get the Asian lady beetles and yellow jacket wasps that bite and sting. The little apples will be a pain to mow over and difficult to pick up. Would it be a little easier to do some shopping for good commercially produced apple wine and instead plant a spring snow crab apple that flowers beautifully in the spring, produces no fruit and maintains a striking architectural shape without any pruning? I had a dolgo crab for several years while the children were young. We all got involved in the harvest by picking the tree clean of fruit for my wife's delicious applesauce. When the kids got to the age when it wasn't cool to do such helpful stuff, the fruit began accumulating and being shoveled up before every mowing in the fall. After several years of getting attacked by the same pests you describe, we had the tree removed and replaced with something requiring less maintenance.

Q: My son moved into a new house in south Fargo. He is planning on doing dormant seeding on his lawn. This soil is a good Red River Valley gumbo. I’d like your advice on ground preparation prior to planting and what varieties you’d recommend. Would you recommend tilling the soil prior to spreading the seed? We’re planning on spreading straw for moisture retention and preventing water runoff. Any ideas or comments would be appreciated. (e-mail reference)

A: Consider sodding the high-visual and -use impact areas. It gives the instant effect that everyone would like from seed. It is more expensive initially, but when time, energy and other resources are added in, the expenses for seeding versus sodding come out about equal. If seeding is the only consideration for whatever reason, then consider having it done by a hydro-mulching contractor. This provides a weed-free mulch to keep the seed protected from washouts and results in quicker germination. Assuming your son does not have an underground sprinkler system, this would be the best dormant seeding system to use. Next spring, it should pop right up and be very competitive with the weeds. Just scratch the surface with a power rake instead of doing heavy tilling. After the soil is graded and worked up, plant a mixture of Kentucky bluegrass, creeping red fescue and perennial rye. This will give you a good, all-around useful turf. Look for the highest quality seed possible. That means very little inert matter, weed seed and no noxious weeds. Make this purchase locally at a good-quality retail outlet that sells garden supplies. Generally, mixtures like this will recommend seeding 2 to 3 pounds per 1,000 square feet. Double that or whatever is recommended on the package to account for the loss from dormant seeding. Make your purchase decision on the seed quality, not the price. For additional tips on getting your son's lawn established, go to

Q: We are looking to plant two trees in our front yard, which has a septic mound system on it. The people who installed it said we can plant on the far edges of it because the slope on the end is for structure. Our local nursery has some autumn blaze maple trees. Will the roots grow to the mound like a silver maple does? Are there any other trees that we could use? (e-mail reference)

A: The autumn blaze is a hybrid of silver and red maples, so it has some of the characteristics of both trees. While I have not heard of the roots of this hybrid being a problem, you can be sure it will not if you have BioBarrier installed between the tree and the septic system lines. You should be able to find a local contractor who installs BioBarrier. This will give you some extra assurance that you will not have a future problem.

Q: I am interested about your opinion on using an LED grow light. It has 28 watts of power that is equal to 250 watts of regular lighting. It has blue and red bulbs. It is very expensive but would be much cheaper to run. (e-mail reference)

A: Unless you are a commercial grower or where electricity is outrageous in price, I would simply go for fluorescent lighting. It is inexpensive to purchase and run. I honestly cannot say anything about an LED grow light as far as cost goes. However, if it is what you want and will last long enough, then go for it.

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) 231-7123,
Editor:Rich Mattern, (701) 231-6136,
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