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

By Ron Smith, Horiculturist

NDSU Extension Service

Q: I have a Pembina plum tree that was planted last summer. Deer have damaged some of the bark and limbs this winter. What can we do to save the tree? The tree is protected from the deer right now. (Neche, N.D.)

A: The tree should heal on its own based on what you told me. Assuming the tree got off to a good start before winter, it should leaf out and slowly seal the wound. If some of the branches are just stubs, wait until bud break this spring and prune them off. Remove anything that doesn't leaf out, but allow as much foliage to remain as possible to help build a sturdy, healthy tree.

Q: I have been enjoying reading your material on the Web. I received an aloe plant as a gift from a friend who started it on her own. I have since transplanted and given away many plants that came from the mother plant. However, the main plant stalk is very large and leans to one side. It also needs to be propped up. What are my options? Can it be cut down? If so, can I repot the cuttings? (e-mail reference)

A: You can repot, but set it deeper in the pot to keep it from leaning. You also can cut it down and repot the cuttings.

Q: A friend gave me his mature spider plant for repotting, but he wants me to use the coco fiber liner in a wire basket. Is this a recommended container for spider plants? If so, how sturdy are the liners and how long do the liners hold up? What type of soil should I use? Also, if tap water is left in an open container for several days, will the chemicals harmful to plants evaporate? (e-mail reference)

A: The coco fiber lining should be just fine. I would guess it will last at least a year, but it will depend on the environmental conditions where the plant is housed. Use any well-drained, pasteurized potting soil. Only those chemicals in the tap water that can volatilize will disappear. The mineral contaminants will not.

Q: We have an old (10 years) jade plant that is large and beautiful. It gets eastern exposure, with direct sunlight on winter mornings and bright light for the rest of the day. The leaves are not firm, although the plant has lots of leaves and seems to be healthy. I generally water it every two weeks. However, since the leaves are not firm, I'm never sure when it needs water. We live in New Mexico and have radiant floor heat, but we don't usually heat the living room because we get so much sun. Recently, some of the leaves (perhaps a handful each day) have started turning yellow and shriveled. I have noticed some spider web material on a couple of branches, but not all over. It is too large to take to the shower to rinse. We can barely move it at all. Any suggestions on how to deal with this problem? (e-mail reference)

A: Nothing lasts forever, but you've come close with this jade, especially one this large. Spider mites can be controlled by spraying some water on the plant or using insecticidal soap. That should knock them down. The plant probably is pot bound. Even though the plant is almost unmanageable, it could stand to be divided and repotted. Other than this, I don't know what else to suggest. Take some leaf or stem cuttings and root them in case this one kicks the bucket. I assume you have read my entries about jade plants on the Web. If not, go to for more information.

Q: I have two azaleas. Until reading your Web site, I never knew they were so difficult to keep. One of the plants was purchased last spring and kept outside. It bloomed with beautiful, unique flowers. I brought it in when it started to get cold. I received the other plant as a Christmas gift. It was in a container that was too small, so it dried out quickly. I repotted it, but all the leaves had fallen off. Now both of them are barely hanging on. What can I do to revive them? Will they ever be beautiful again? They are located in front of a window. It is too cold to put them outside right now here in Kentucky. Can they be planted outside permanently? Do they have to be brought back inside during the cold? They are very pretty, so I'd hate to have them die. (e-mail reference)

A: I wish I could give you good news, but I can't. The ones sold at retail outlets during the holidays are not winter hardy in your area. If you lived in central Georgia or further south, then you would be able to leave them outdoors. They just do not survive the long winter months indoors in the north. Enjoy their beauty while you can, then dump them when the flowers fade.

Q: I found your Web site about a week ago by accident and have been avidly reading it ever since. Your knowledge of plants is obviously extensive. I'm sure you have forgotten more about plants than I may ever know. I thought I would ask a question as well. I am located in Alamance County, N.C. I have 10 weigela bushes planted along a section of chain-link fence. The bushes have been doing great for the last 10 years. I have been pruning them back every year into a hedgerow. This has never seemed to be a problem and the bushes have vigorously grown back, produced lots of flowers and grown leaves from the top of the bush all the way to the ground. However, last year the bottom portion of the bushes did not come back as well as expected. The leaf cover was somewhat thin. In my area, I have seen too many hedgerows that seem to have lush greenery on top, but the bottom half of the plants are bare or just a collection of sticks. What is the proper care for hedges and how do I keep this fate from happening to my weigela? Also, I noticed that your advice on pruning weigela generally includes cutting some or part of the bush to the ground (which I have never done). Would cutting these trunks to the ground pose a threat to the plant? Any advice you could give me would really be appreciated. (e-mail reference)

A: If the hedge was healthy last year (not counting the bare sticks at the base), then the plants should be able to tolerate being mowed down this spring. The bushes should rebound for you with a flurry of flowers this growing season. In future pruning, tend to do so in an A shape (wider at the base and narrower at the top). This will allow sunlight to reach the sides of the plants better and keep them in full leaf. About every two to three years, prune out the oldest or thickest canes right to the ground. This will keep the plant full and lush.

Q: I live in Hesperia, Calif. (high desert). The temperatures get as low as 24 degrees in the winter and as high as 115 degrees in summer. There are juniper bushes along the property line and a row in the middle of the property. I don’t know how long they went without water before we moved in. I water them three times a night for 20 minutes each time. We have lost five of them and the others are turning brown. Is this a problem that can be resolved? Any help would be greatly appreciated. (e-mail reference)

A: Stop watering so much! Junipers are well adapted to the high desert environment, so your overwatering is killing them. Unless these are very puny seedlings attempting to get established, they can get by with a good soaking every 10 to 14 days or less.

Q: I am new to peonies. I bought a plant last spring (it had several blooms on it at the time) and planted it in a nice place in my yard. I was out removing last fall's leaves from around the plant when I realized that new buds have formed, but are not pointed up. The buds are pointing to the left or right. In one case, the bud is pointing downward. I am afraid this will affect the growth of my plant. Should I dig it up and replant it now or wait until fall? Any suggestions would be welcome. (North Carolina)

A: I'd suggest waiting. The plant should do OK for you this year. If not, dig it up and reset the plant this fall.

Q: I have a silver maple that is about 40 feet tall. It seems to be doing fine, but the bark for the first 15 feet is splitting. Is this normal? (Colorado)

A: It’s probably normal if it is confined to the bark. If you are seeing heartwood, then it could be sunscald, but I doubt that sunscald would occur on a tree this size.

Q: I bought a plant called Mexican ivy, but cannot find any information on it. Can you tell me if such a plant exists? If yes, how should I take care of it? (e-mail reference)

A: It must be a very rare plant because I cannot find any information on it in my references or anywhere on the Web. Sorry! I'd suggest going back to the retailer that sold it and request that information be supplied. Plants without cultural information in print or from the seller should not be sold.

Q: I have enjoyed reading your solutions to weed control problems on your Web page. Thank you! Every year we get foxtails and goat heads (not sure if that's the correct name for them) in our backyard. These goat heads are nasty little round balls loaded with extremely sharp stickers! In early spring, we don't dare let our grandkids or dogs go into the yard because it's dangerous! I have been using Weed and Feed, which helps the yard get beautiful. However, I must be missing places because these nasty weeds keep coming up, especially in early spring. Your Web site discusses pre-emergence herbicides containing pendimethalin for the foxtails. Would it also help get rid of the goat heads? Thank you for your guidance (California)

A: Yes, pendimethalin can be used to control these pesky and painful broadleaf weeds. However, nothing is ever 100 percent effective, so you need to be diligent in other management practices. Recognize the weeds before they flower and hand pull them. Keep in mind that the seed from these weeds can remain dormant in the soil for up to 10 years. Even if you are successful at getting the entire crop pulled out, there may be more seed lurking in the soil that will surprise you with a painful puncture on a bare foot! Also, do all you can to develop a dense, healthy lawn. Weeds cannot compete with healthy, vigorously growing grass. These weeds are opportunists that move in and get established in weak, thin turf.

Q: We have two rows of blue spruce trees that we planted six years ago. We had an Extension Service agent look at the trees because they were losing needles and turning brown. The agent thought the problem was needle cast and told me to spray them with a certain spray that I found about 60 miles from where I live. Can blue spruces be saved if they have needle cast? They are planted about 25 feet from some walnut trees. Does that make a difference? They also don't seem to grow very fast. Is that normal? Please help. (e-mail reference)

A: Blue spruce trees grow slowly and are subject to needle cast. Growing that close to walnut trees may become a problem, depending on maturity. The roots and leaves of walnut trees exude a material known as juglone, which is an allelopathic compound that inhibits the growth of certain plant species. What the effect the walnut trees would have, if any, on the spruce trees is something that I don't know. A timely spraying with the proper fungicide will help control the spread of needle cast. It should be carried out for three consecutive years to be effective. Regular monitoring should be done after that to catch the disease in its early stage and before too much damage is done.

Q: I was reading all of the questions you have listed on your Web site, but I did not see if you gave an answer about spider plants being poisonous to cats. I have a cat and my girlfriend has a cat. My cat has never touched the plant, but her cat was caught nibbling on the leaves. We moved the plant, but, as everyone knows, cats will go just about anywhere they want to. My girlfriend is worried because her cat has been acting a little weird (the cat is weird), but I need to know if we should be alarmed. (e-mail reference)

A: We own three cats and three spider plants. While they are hanging, the cats cannot get to the plants. However, when we take the plants down to water them in the tub, we get all kinds of help from the cats. That includes nibbling on the plants the instant we turn our backs! We see the contents of their nibbling a little later on the carpet, but the cats are otherwise OK. These are older cats, so I would guess the plants are not poisonous to them. However, you should discourage them from nibbling on the plants whenever possible.

Q: The instructions for planting strawberries and what type to plant seem so complicated to me. What would happen if I planted some and kept them mulched and weeded without all the other stuff, such as cutting off runners and blooms? (e-mail reference)

A: You'd get some strawberries, but not as many as you would otherwise. It is quite simple. Don't allow the plants to set fruit the first year to get maximum production the following year. If you let the plants get runners, they will move into your lawn or surrounding flower beds, which may or may not be something you want. When I moved to North Dakota back in 1985, I planted a cutleaf weeping birch tree and planted strawberries underneath it. The purpose was to provide a mock woodland environment for the root system of the tree so it could get established. It worked because the tree is still standing and beautiful after more than 22 years. The strawberries disappeared long ago due to any number of factors, but mostly benign neglect on our part and the desire to have something else growing there. However, while they were there, they flowered, produced fruit and fed the robins. We just got enough to taste for ourselves, which may end up happening to you if you have robins that inhabit your community during spring and summer.

Q: I have two questions. I have a large-leaf jade that dropped all but a few leaves. New ones are growing and everything is healthy again. This happened during the summer. Do you know what could have caused this? Do you know how to get a jade plant to flower? A friend's blooms almost all the time. (e-mail reference)

A: Being tropical in origin, it likely read the summer temperatures and weather conditions as the equivalent of a dry period in the tropics. You have nothing to worry about. For flowering, it is a hit- and miss-situation. I doubt that your friend has one that flowers all the time. You might ask her what cultural techniques she follows and then try to ape those practices as much as possible. However, don't get frustrated because these plants seem to have their own peculiar behavior patterns. In other words, it all depends on who the mother plant was that the cuttings were taken from.

Q: I have had a dieffenbachia that has grown considerably in the more than two years I’ve had it. I quit feeding it during the winter months, but have watered it approximately every two weeks when the soil feels dry. It has continued to grow great. However, in the last two weeks, I've noticed that four of the medium-sized stalks with leaves have layed down. The stalks are hanging over the side of the pot. They aren't limp. Instead, it appears the stalks are growing downward. I thought this may be from not getting enough sunlight, so I repositioned the plant to encourage these stalks to perk up. However, I'm not having any luck. The other stalks are very sturdy and standing straight. The sturdy stalks also have very green leaves. The leaves on the stalks lying down also are green and show no signs of turning yellow or brown. Do you have an explanation for the problem or is there not even a problem? The plant doesn't look nice and healthy with stalks hanging everywhere. Thank you very much for your time. (e-mail reference)

A: If the plant is healthy, but these particular plant parts are distracting to the overall beauty and character of the plant, remove them. It shouldn't harm the plant.

Q: I have seen charts available on the Web that suggest dates to plant different types of vegetables or fruits in the garden. All the information is given in relation to an area's frost-free date. I'm sure these dates vary from year to year, but could you give me some guidance as to approximately when the frost-free date is set for Fargo? Also, what should I be looking for as far as knowing when the date has come? Thank you so much for your help! (Fargo, N.D.)

A: Frost can occur during any of the nonwinter months, so there is no safe date. On the NDSU campus, we wait until we get within a week of Memorial Day weekend to begin our variety trial plantings. Many people will plant earlier in an attempt to get an early start on the season, but then they have to cover the plants when a frost threatens or when extended cold, windy weather is forecast. If your gardening attempts are modest and you don't mind monitoring the weather, you certainly can start earlier. Lots of people do.

Q: I hope I am sending this request to the proper address. I am not familiar with this Web site and apologize if I am supposed to handle this a different way. I hope you can help me, though. I read with fascination the tons of e-mails about autumn blaze trees. However, none seemed to cover all my problems. I planted a lovely autumn blaze last fall. It is planted in clay soil and gets full sun. It did beautifully in the spring until the sprinkler system came on. The sprinkler poured water on it for a couple of months before we realized it was stressing the tree. We turned off the irrigation system and some of the tree’s color came back, but it still is light with dark veins. Now it is getting black spots on the leaves and some are curling. We have had some really nasty rains the last few weeks. From what I read on other e-mails, I should not apply anything and hope for the best. Is this the course of action you recommend? (e-mail reference)

A: That is the best course of action at this time. Hopefully, the tree will recover on its own. If you want to try to erase some guilt, you could do a core aeration or auger aeration around the canopy edge of the tree. Since saturating the soil tends to compact it, the available air in the soil profile is greatly reduced, which makes it difficult for the tree to actively absorb nutrient minerals. The result is the chlorosis or yellowing you describe.

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
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