You are here: Home Columns Hortiscope Hortiscope
 
Document Actions

Hortiscope

Ron Smith answers questions about the world of plants, trees and gardens.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I have a huge bleeding heart that I would like to prune because it has taken over my flowerbed. I also want to transplant some of the cuttings. I never have done anything like this before, so I hope you can give me some advice because I don’t want to hurt the plant. (e-mail reference)

A: Bleeding heart can be divided and transplanted in early spring or late fall, but early spring is the better choice. The cuttings also can be rooted. I doubt you seriously can hurt a plant with this much vigor.

Q: I have four lilacs that I planted about three years ago. On two of the plants, almost every leaf looks like someone took a pair of pinking shears and cut the edges off the leaves. I assume something is coming out at night and chewing on the plants because I've never seen any bugs on them. The plants appear to be healthy otherwise. Can you suggest a treatment? (e-mail reference)

A: Get some Bayer Advanced Tree and Shrub Insecticide, which is systemically active. Follow the directions exactly for proper application. The night pest will not eat too many more times after that.

Q: We have a large cottonwood tree that has a number of clusters of hanging green growth. The clusters are about the size of a cluster of grapes. There is more this year than last year. I assume that this is a parasite. What is the cure? We also have a narrow-leaf cottonwood that has small, brown clusters on the small branches. These also are more prevalent this year and we are beginning to find them on nearby cottonwoods. These clusters are about the size of a dime, hard and brown. (e-mail reference)

A: These are either petiole or flower seed galls. My thoughts favor the flower seed galls. At this stage, there is nothing you can do. The cure, which is spraying with a miticide early in the spring, isn't worth the expense or environmental impact. Other than looking unsightly, the galls are not lethal to the trees.

Q: We need help with our newly planted trees. We planted a pear, plum and ash tree that are getting round, yellow circles on the underside of the leaves. When you look at the circles, they have small pin dots of a darker yellow on them. It is causing the leaves to curl and dry up. We had the same problem last year and were surprised the trees came back again. What could this be and what can we use to spray the trees? Please help because we hate to see our trees look like they did last summer. (Gackle, N.D.)

A: This sounds like a rust fungus getting started on your trees. Get some Funginex or Bordeaux mixture fungicide and apply it according to the directions. The fungicide will control further spread to uninfected leaves. Early next spring, but before leafing out takes place, spray the trees with lime-sulfur. It is a good sanitizer and will help prevent a recurrence of disease organisms. Follow up with a spray of one of these fungicides once the leaves have fully expanded, but before the pathogen shows up again.

Q: I have blight on my tomatoes. The plant is growing and starting to bloom, but the new leaves are curling. Now the peppers are doing the same thing. I have sprayed with a fungicide and malathion, but that didn’t work. Miracle-Gro is keeping them from dying. I picked off all the curled leaves. We put barn lime in the garden this spring. Would that hurt the plant? (Eureka, S.D.)

A: The leaf curling is not blight as long as the leaves are still a normal color. Transplanting, accompanied by the cool, rainy weather, usually causes this phenomenon to show up. It doesn't hurt the plant and there are no sprays or cultural practices that you can follow that will prevent this from occurring.

Q: We planted a weeping birch this spring. We are in southern Alberta. It looked like it was doing wonderfully until this past week. The wind snapped a lower branch, which we need to prune off. However, the leaves at the bottom are turning yellow. We did put down sod around and close to the trunk of the tree. Could you please advise us as to what the problem might be? (e-mail reference)

A: The sod is definitely a competitor for water, air and nutrients. Pull the sod back a minimum of 2.5 feet from the trunk of the tree and give it a shot of Miracle-Gro to help it recover. Also, check the planting depth to be sure it is not planted too deeply. Look for the roots to be flaring out at the surrounding soil line. If they are not visible, pull the soil back until they are visible. Then mulch lightly with bark or peat moss to keep the roots cool. The mulch should be no more than 2 inches thick.

Q: I have peonies along my property line, but would like to put up a cedar fence instead. Can you tell me how to get rid of the root system so that when I put up my fence, I won't have peonies growing there? I tried Roundup, but that didn't seem to help at all. Hope you can help! (e-mail reference)

A: The only help I can offer is to dig them up. Usually, getting rid of the crown where the regenerating buds are will spell doom for peonies.

Q: My two sons, ages 5 and 3, were the proud growers of sunflower seeds. They started them growing in cups in May, but since have been repotted and moved outdoors. We also moved some other plants outside. The pots were placed on bench seats at least 2 feet above our deck. I put the smaller sprouts in the garage for climate control. The next morning, the sunflowers had been cut about half way up the stems and about 2 or 3 inches were eaten out. I left them out after that and now all of the stalks and leaves have been eaten. After discovering the first dinner of sunflowers, I moved all the plants, except a large tomato plant, into the garage for climate and critter protection. The beans I planted have seen the sun from atop a red Flyer wagon when I'm there to supervise. They spent last night in the garage. However, this morning there was one beanstalk that was eaten about 12 inches up the stem in the same straight cut across the stem as the sunflowers. We do have bunnies in our yard, but there is no way they would have access to our garage, especially when it is closed. We have squirrels in the yard as well. I blamed the squirrels for the sunflowers, but I don't believe they would have access to our garage. Short of putting in a video surveillance system, I was hoping you might have some idea of what animal likes to munch on my kid’s potted garden plants! (e-mail reference)

A: What an interesting puzzle! Are you sure your sons don't have jealous competitors? What you describe to me just doesn't jibe with any critter I know of that could cause that kind of damage. If you ever figure this one out, please let me know. Sorry that I can't come up with a flash of insight to provide an answer for you!

Q: I just read your comments on hybrid elms. I planted a hybrid elm back in 1968 and it is fast growing. However, you talk about a trashy tree! Had the nursery disclosed that it was from a cross of a Chinese elm, I never would have planted it. You had better love picking up trailer loads of limbs before you mow each week and heaven help you if you have strong winds or ice storms! The weight of the tree is so unbalanced, so I need to take it down to the tune of just more than $1,000. I often wish I had never heard of this tree. I would never recommend this tree for anything or anybody. The problems that come with it far outweigh the quick shade. (e-mail reference)

A: Allow me to clear up some misconceptions about hybrid elms. The term Chinese and Siberian continue to be confused in the professional trade. That is why common names should be tied to botanical names! The Chinese elm is a beautiful tree that is moderate in growth rate, has a stable and solid crown and flowers/sets seeds in the fall. The Siberian elm is a weedlike tree that has fast growth and Dutch elm resistance as its only attributes. It has no architectural value to it and is a magnet for diseases and insects. The slightest herbicide drift will cause damage. In spite of the truckloads of kindling it produces, the blasted tree never dies completely. Not all hybrid elms are crossed with the Siberian elm. In fact, when a nametag is on an elm tree calling it a hybrid elm, check to see if the botanical names are listed for the cross. If the common names are the only ones used, be a skeptic about getting the real thing because the two elm names unfortunately are used interchangeably, so the client doesn't know what he or she is getting. In your case, you obviously were stuck with the Siberian elm that was called a Chinese elm. As a representative of the horticulture profession, I apologize for this shortcoming.

Q: When is the best time to prune a snowball bush? Only portions of my bush bloom each year. However, it was covered with blossoms this year. I have not been consistent with pruning. Does it bloom on new wood or old wood? (McVille N.D.)

A: A snowball (I think you mean the Annabelle hydrangea) blooms on new wood.

Q: I have a question about our crepe myrtle tree. I noticed that the flowers seemed to be drying up. After a closer look, I found that the flowers were turning to round, green, seedlike things. It looks like a small bunch of green grapes where each flower was. What is causing this and how do I get the flowers back? (e-mail reference)

A: Those are seedpods. To get the plant to reflower, prune the seed heads off. It’s the nature of the beast.

Q: I have an apricot pit that I would like to grow. I was wondering how to start it. Would I start it inside in a pot and then transfer it outside? (e-mail reference)

A: Plant it where you want it outdoors. It will not grow until next year if it is going to grow at all. The pit (seed within) needs to go through a freezing winter to be able to germinate. Good luck!

Q: I have a lilac shrub. Last year, after it finished flowering, I noticed that the leaves at the top of the shrub were starting to turn brown and die. I assumed this was a watering issue (we were having a drought year). I pruned the branches that had dying leaves and hand watered the shrub in addition to the watering it got from the sprinklers. This year, the lilac looked great, but had some light browning on the leaf edges, which reversed after giving it extra water. The lilac bloomed and looked great. Then, just like last year, the leaves at the top of the shrub started getting brown and dying. Since I have been watering it regularly, I don't think it is a watering issue. What do you think is happening? Thank you for your help. (e-mail reference)

A: The problem could be coming from your watering overhead with the sprinklers. It sounds like a fungus has established itself on the plant and is being stimulated in some way by water on the foliage keeping it wet too long. Try changing that practice to see if that helps. Also, look for a fungicide called Funginex to apply.

Q: I was reading through your Web page and noticed someone had a similar problem as I do with lilies. I bought two peace lilies. Soon after bringing them home, I noticed that I had millipedes in the soil. I purchased them at a store where I work. I asked the person in charge of the department if he noticed them in any other plants at the store. He said no and checked a few more times to put my mind at ease. Anyway, I took the plants outside and removed all the soil from the roots. I didn’t think to let them completely dry out before replanting in brand new Miracle-Gro potting soil. You told the person in the e-mail to bring the plant and what was left of her potting soil back to the store to get a refund. Is there anything I can do to get rid of the millipedes? I also used the potting soil in my garden. Will I have millipedes outside everywhere? Are they harmful to plants or just a nuisance? I have been picking them off with tweezers and killing them. (e-mail reference)

A: Millipedes feed on decaying organic matter, so the cleaner the soil (pasteurized or sterilized), the fewer you will have. They are pests only and do not harm plants.

Q: I recently spread humus in my flowerbed and yard. However, now my coneflowers are falling. Also, my butterfly bushes and Asiatic lilies are turning yellow. Please help because I don't know what to do. (e-mail reference)

A: It sounds like the humus was contaminated with something. I don't know what to suggest, but try giving everything a shot of fertilizer to see if that helps.

Q: We have a property located in Redding, Calif. Our tenant's horses have chewed the bark off a number of oak trees (some are completely ringed). Are these trees in danger? They appear healthy, but this damage has occurred within the last six months. Will the bark regenerate and the trees heal? I'm very concerned about their health. (e-mail reference)

A: If the bark is completely removed (ringed as you stated), they will not live beyond this year. There is nothing you can do about it. Sorry!

Q: I planted willow trees last fall. They are now tall and appear to be very healthy. However, the least little bit of wind causes them to bend to the point that one of them lays on the ground. I now have them staked to keep them off the ground. (e-mail reference)

A: Willows normally do not need staking. If you are going to use stakes, make sure the trees can flex in the wind. If you keep the trees too tight, they never will develop stress wood, which makes them resist just what you described your willows as doing. Remove the staking material in a year. They should be able to stand on their own by then.


NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161, ronald.smith@ndsu.edu
Editor:Rich Mattern, (701) 231-6136, richard.mattern@ndsu.edu
Columns
BeefTalk: BeefTalk: Reproductive Performance in Commercial Beef Herds is Remarkable  (2017-11-22)  As a whole, today’s cattle reproduce very well.  FULL STORY
Prairie Fare: Prairie Fare: How Much Do You Know About Frozen Food Storage?  (2017-11-22)  Freezing is one of the easiest and most convenient ways to preserve food if you have the proper equipment.   FULL STORY
 
Use of Releases
The news media and others may use these news releases in their entirety. If the articles are edited, the sources and NDSU must be given credit.
 

Powered by Plone, the Open Source Content Management System