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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I would like to have my soil tested for recommendations on how to improve it. How do I find you? How much soil should I bring? Also, my pear trees are blooming but there doesn’t seem to be any bugs around to help with pollination. What should I do? (email reference)

A: You can send a soil sample to me at the address at the end of this column. Take a Ziploc sandwich bag and fill it with soil that is representative of where you will be planting. The soil will be tested for nitrogen, phosphorous, potash (potassium), pH, organic matter and soluble salt content. The cost will be around $25. You will get recommendations for any adjustments that might need to be made to grow the crop(s) you describe in a note you include with your soil sample. There are plenty of bugs out and about. I must have killed 10,000 of them last night coming back from a trip.

Q: An oak tree in our front yard has hordes of small, grayish insects hanging on the underside of many of the smaller branches. They appear to be sucking out the sap, and the leaves on the branches never bloomed. They don’t move much, but they are mobile. Do you know what they are? What can I do about them? (email reference)

A: I cannot tell from your description what the insects are that are stealing the life out of your tree. Contact an International Society of Arboriculture certified arborist to spray the tree or inject an insecticide into the trunk. The need might be there for both. Spraying would knock down the population quickly. An injection later using a systemic would make sure the population is eliminated. Go to to locate an arborist in your area. Be sure to check credentials before allowing any major work to be carried out.

Q: My husband and I are interested in planting some apple trees on a farmstead. What species do you recommend? We are curious about golden delicious, which is a jonalicious-type graft, or a honeycrisp. What pollinators would be needed? We're not crazy about granny smith or crabapples. (Manning, N.D.)

A: I have a publication I put together after some extensive research. Go to for the information you want. You can download the entire publication if you would like. If you have any more questions, get back to me. I hope it helps!

Q: I have a question about some willow twigs that I have. On Valentine's Day, I got a bouquet of flowers with two willow twigs in it. The twigs started to sprout roots and leaves. Ever since then, I've had them in a vase of water that I change twice a week. The vase is on a window sill, so there is plenty of sunshine. It seems like they've been doing really well and constantly have been sprouting new leaves and roots. I was wondering if these twigs could grow into trees if I planted them in a pot of soil. I've been meaning to do this but I have been afraid that I would do it wrong and they would die. Please let me know what I should do with them. Thank you so much for your time! (email reference)

A: Yes to both of your questions. I’d suggest potting them and gradually hardening them off by giving them some outdoor exposure on nice days. Start with a couple of hours in a protected location away from direct sun and wind. Gradually increase the time outdoors and exposure to the elements. Plant the twigs sometime around the Memorial Day weekend.

Q: I had early and midblooming tulips in a window box. The early tulip bloomed, as did others in the planter. After that, the midblooming tulips started to come up and bud. However, I think I left the window box without water for too many days. The fully bloomed tulip started to dry out, while its cohorts in the planter still were healthy. I then realized that the small buds of the midspring tulips looked dried. Now the midspring tulip buds have started to shoot up in the planter, but nothing more is happening in the window box. Is there anything I can do to save the window box tulips, such as trim them? I watered them right away when I realized they were drying out but it's not helping. Compared with the planter tulips, there is obviously something wrong. (email reference)

A: If the window box tulip foliage is green and firm, there is a chance they will survive. Keep the soil well hydrated but do not overwater. Allow the foliage to go through its normal die down later this spring or summer. Window box plantings often catch people off guard as far as watering goes. The plants usually need a daily watering.

Q: I have a new spider plant that appears healthy. However, I've just noticed dozens of pinhead- sized, charcoal, six-legged bugs on the stems and flowers. They are very slow moving and don't seem to be eating the plant. I'd like to get rid of them in case they are harmful or will infest my other plants. Any suggestions on a product or process to get rid of the bugs? (email reference)

A: I’m not sure what these critters would be on your spider plant. However, they can be controlled with a spray containing pyrethrum. Get it in a pump spray rather than a pressurized one because the pressurized container may burn the foliage. I would encourage you to isolate the spider plant when doing this and keep it isolated while you monitor the plant during the next few weeks to be sure of a complete kill. Repeat the application as needed and also check your other houseplants.

Q: Your website is great with questions specific to lilacs. I have two bushes that are about 4 years old. Both bloomed for the first time last year and produced huge, very full, gorgeous blooms. This spring, the one in the backyard has no blossoms, but it does look healthy. The lilac in the front yard has fewer blooms than last year and looks sickly. Also, the leaves are curling upward at the edges. It has been a drier spring than usual. Can you tell me what might be going on here and what I might be able to do? Thank you. (email reference)

A: The bloom probably was reduced somewhat if you didn’t cut the spent blooms off the previous year. When the shrub utilizes energy to make seeds, flowering the following year is sometimes set back a little, especially on younger plants. The plant with curled-up leaves could be reacting to herbicide drift from lawn herbicide applications in your yard or next door. It could also mean that lilac/ash borers are at work. You need to give it a close examination. If you cannot make a determination, contact your Extension Service agent where you live to submit a sample or to make an onsite inspection.

Q: I have a black walnut that is more than 20 years old. It has not produced leaves this spring. Is there a way to find out if it is dead or just late getting leaves? It has produced black walnuts twice in 22 years. The tree drops its leaves all at once and somewhat late in the fall. (Rapid City, S.D.)

A: Black walnuts usually break bud later than other species. Check the other black walnuts in your area to see if they are equally as behind. If yours is the only one, there is a potential problem. You should get in touch with the Extension Service agent where you live to have him or her see if any disease or insect problems exist. This just may be the genetic temperament of this particular tree or it is reacting to the weird winter/spring weather we’ve had in this year.

Q: My husband and I moved into a house that had black raspberry bushes growing in the small space between our garage and the neighbor's fence. The first two summers, they produced berries. Now the stalks are thick but not producing berries. However, there are new shoots coming up in the garden along the fence. I want to move them to behind my garage before they become too invasive. Should I prune them back before transplanting? Do I transplant all the stalks? How do I prune them? What's the best way to stake or support the bushes after I move them? Thanks in advance for your advice. (email reference)

A: These brambles bear their fruit on biennial cane. They are vegetative the first year followed by fruiting the next year and then die off. Generally, brambles are easy to dig up and transplant. You can dig up the new growth (crowns and all) and move them to the new location. Cut the old canes out completely and throw them away or burn them (if allowed). There are many ways to prune and support bramble growth. The easiest way I found is to select the stoutest three or four canes and loosely tie them together at about waist height. Prune out any puny canes and throw them away. When they get too tall, cut the canes back to about shoulder height to make them branch out more. You then are done for the season except for harvesting the delicious and healthy berries they will produce.

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

NDSU Agriculture Communication – May 3, 2012

Source:Ron Smith, (701) 231-7971,
Editor:Rich Mattern, (701) 231-6136,
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