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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I have a jade plant that has been flowering for about two months and is very beautiful. My concern is that I have no idea what to do with the plant after it finishes blooming. Do I have to trim the tips of the branches? Thanks! (e-mail reference)

A: You are experiencing a rare treat, so enjoy! Once the flowers are finished blooming, remove the spent blooms and allow the plant to grow with normal care. This usually is a once-in-a-lifetime experience with a houseplant.

Q: I just inherited a ficus tree that I know nothing about. I'm usually good at bringing plants back to life, but this ficus tree is bumming me out. The owner was about to throw it away because she thought it was dying. It still is green under the bark, so I know it's still alive. I believe it's in shock because the leaves are drying up and falling off. I know it went through a lot before it came to me. Please help me pep this poor thing back up! (e-mail reference)

A: I have no magic words or snake oil recommendations that will help you. I suggest that you keep the soil barely moist and be patient. As long as the cambium is still green under the bark, there is hope. It might remain dormant through the winter months. After spring arrives, placing it outdoors might perk it up. Right now, patience is the best approach to take. There is nothing to inject into the soil or plant that will pull it out of this funk.

Q: I’ve had two jade plants for four years. About all that happens is that the top leaves get a little bigger. The plants are green and stand up on their own, but one of the stalks is loose in the soil. What gives? (e-mail reference)

A: The plants don't like something in the environment or there is a problem with something that you are doing or not doing. Jade plants need strong, indirect light. Direct sunlight would be OK during the winter months. To correct the problem with the foliage at the top, I would suggest that you cut the stalk back and cut the pieces into 4-inch lengths for rooting. Lay the cut pieces in a bed of damp, unmilled sphagnum moss that barely covers the stalks. In six or so weeks, there should be some leaves coming from the top part of the cuttings and roots developing at the base. After the roots get to ample volume, pot the cuttings in a pasteurized media. The leaves then will reorient themselves to the light and you will have new jade plants to give to family and friends. As for the stalk that has no roots, that is because of deficient leafing volume. You probably cannot change what already has taken place, so I would suggest dumping the plant and replacing it with one of the newly-rooted plants.

Q: My sister gave me two silver maples to plant. However, the maples look more like bushes than trees. When should I start pruning so I can get them to look more like trees? Which branches should be pruned off and which should stay? How many should stay? (e-mail reference)

A: Give them a year to get established and then prune about one-third of the lower branches back to a main stem or trunk. Do this after the trees have leafed out in the spring to cut down on excessive sap flow. Repeat each year until you are satisfied with the canopy level and spread that you want. From then on, keep sharp eyes out for any V-shaped branch connections developing. If that happens, remove the lesser of the two branches to prevent problems later on.

Q: I bought a small ficus. About two to three weeks later, I noticed the plant had white, cottonlike material on the bottom of it (I could see it through the drainage holes). I decided to repot the plant using new soil and a new pot. About a week to two after repotting, I noticed the white stuff was back. I noticed the white stuff also is in my peace lily. It definitely looks like mold. I may have overwatered the peace lily slightly, but I'm sure I haven't overwatered the ficus since replanting it. I'm not sure what to do. The ficus has begun to drop healthy, green leaves like crazy and the peace lily is drooping. I don't want the peace lily to die because of its sentimental value. What can I do? (e-mail reference)

A: The peace lily probably is attempting to enter dormancy. Allow it to dry down and cut off the wilted and dry leaves. Give it a minimum of six weeks in a cool, dark location, such as your basement, and barely keep the soil moist during that time. Eventually, some new growth should emerge. After it does, move the plant back to normal light and begin your regular watering cycle again. Peace lilies are hard to kill, so don't worry. The leaf drop by the ficus should end soon. The plant will keep the foliage it can maintain. As for the mold, it shouldn't be hurting either plant. I trust you are using pasteurized or sterilized soil. If not, get some and repot. Anytime you repot, always wash and sanitize the container if you are going to use it again. Overwatering and underlighting kill houseplants faster than anything else. You've recognized that you may be overwatering; now ask yourself if the plants are getting enough light. In most cases, they are not. Use a plant light that is set up on a 12-hour schedule.

Q: I found your Web site after someone told me that I may have planted a weeping willow too close to my house. I have a damp area about 20 feet from the back of my house, so I thought it would help to plant a weeping willow. Between the house and the willow, there is large French drain that handles runoff from the gutters. In winter, this area stays waterlogged, but I’m hoping the tree will reduce the problem. I planted it less than six months ago and it is doing very well. However, a friend told me that a willow should be at least 60 feet from a house because of its intrusive root system. I am wondering if pruning will limit the size of the tree. If so, will this have a corresponding impact on the extent to which the roots travel? (Philadelphia, Pa.)

A: I wish truth traveled or got around as efficiently as does fiction or hearsay! Plenty of willow trees planted are planted 20 feet or closer to a house without negative consequences to the foundation from the roots. Roots will follow the path of least resistance. In your case, it will go with the flow of water. You only have to worry about roots if your basement has leaky, weak walls. A willow tree should be trimmed very little so it can show off its magnificent architectural shape as it matures. One thing you will have no matter where the tree is placed is plenty of kindling. For some homeowners, it is a headache that causes them to regret ever having a willow on their property. For others, it is another small chore to perform before mowing to have a neat looking yard. It sounds like your tree is doing exceptionally well. I would encourage you to leave it in its present spot and enjoy watching it grow. Don't be afraid to do some selective pruning or have it done professionally. Selective pruning will minimize the kindling that collects under the canopy.

Q: Some years ago, I saw a hanging plant that looked like a wandering Jew, except it was red. When I asked about it, I was told it was a spider plant. Is there a spider variation that would look like that or was it another plant? (e-mail reference)

A: I think it must have been a wandering Jew (Tradescantia gigantean). Sometimes common names get turned around and are used for multiple species. A true spider plant (Chlorophytum comosum) is either all green or variegated. If there is a red foliated form of this plant, it is a pretty good secret to lots of people.

Q: I had a guy stop by the office with a rose question. This year he has all kinds of seeds from a rose bush and is wondering if he can plant the seeds and when is a good time. The seeds look to be inside a seed ball. His rose bush is very hardy, so that is the reason why he wants to plant the seeds. (e-mail reference)

A: Rose seeds are contained in what are known as hips. Remove the seeds from the hips and then rinse them in a solution of bottled water and 5 percent bleach. Follow up with a rinse in pure water, but pouring it through a strainer. Soak the seed in a solution of peroxide for 24 hours. After that, remove any seeds that are floating because these seeds usually are not viable. Then put the seeds in a blender with pure water to remove any pulp that might be remaining. Plant the seeds in pasteurized soil and put them somewhere where they can stratify for six to nine weeks at about 35 to 40 degrees. Old salad trays from fast-food places are ideal because they have covers that can be closed to keep the seeds moist. After the six to nine weeks, plant the seeds in a plant tray and place them under plant lights so they germinate. Don't expect overwhelming success. If it was easy, everybody would be able to do it and we'd have a world full of amateur rose growers!

Q: We are looking for a small ornamental tree for our backyard that will be fairly close to our pond. We've been looking at spring snow and thunderchild flowering crab trees. I think these trees will grow to about the size we want. We do like the red foliage on the thunderchild. Do you have any recommendations? In particular, I would be interested in disease-resistance and tendency to sucker. (e-mail reference)

A: Thunderchild is a good tree for leaf color and is seen around the Fargo-Moorhead area. It is disease resistant, especially to fireblight, but has shown some scab susceptibility in recent years. However, it has not shown enough susceptibility to warrant elimination from consideration. The flowers start out pink, go to red or rose and then fade to white. The fruit is a dark purple and relished by birds. Spring snow is fruitless, but has beautiful, white flowers in the spring. Unfortunately, it is quite susceptible to all the typical apple diseases, such as scab, cedar-apple rust and fireblight. Neither variety is noted for suckering at the base.

Q: When is the best time to harvest seeds from my morning glories? Does the petal need to dry up first or do I need to get them immediately after blooming? (Texas)

A: Morning glory seeds hold their viability quite well. You can plant them immediately after the pod dries or put them in a cool, low-humidity container for a couple of years with little loss of viability.

Q: I planted three birch trees off our deck last fall. Two are doing well, but one has a problem. It didn’t leaf out on the top half of the tree. The bottom portion, about 75 percent of the tree, looks fine. I waited all summer, hoping it just needed some time to awaken. I read in Hortiscope that the problem could be borers. Can I apply Bayer Advanced? If yes, when would be the best time and should I then reapply in early spring? I live in northern Illinois west of Chicago. (e-mail reference)

A: It sounds like symptoms of borer damage. Applying the Bayer product now would be acceptable, but not as effective as it would if you applied it in the spring as new growth emerges. Right now, the tree is starting to shut down for the season and is not transporting upward as much as it would in the spring. I also would cut out the dead part of the tree to a lateral branch, but don't leave a stub.

Q: We have two hibiscus bushes that have been in the ground for more than two years. They are planted 15 feet apart from each other. About two months ago, the younger of the two started to turn yellow at the base of the bush and slowly made its way upward. As time went by, almost the entire brush turned brown. The parts that are green still have blooming flowers. Can you explain how to care for it or what the problem is? (e-mail reference)

A: My first suspicions are overwatering, poor drainage, root rot or a vascular disease, such as verticillium wilt. There is no way of telling without a lab test. The conditions you describe lead me to believe the plant is on its last legs. Scrape the bark off one of the dead-appearing branches to see if there is any green cambial tissue. If there is, then a chance remains that the plant may recover if the cause of the symptoms can be determined.

Q: What would keep a crepe myrtle from blooming? I have a white one that blooms every year and a pink one on the south side of my house that rarely blooms. Could you help me out? (e-mail reference)

A: Your problem could be lack of sufficient sunlight, temperature fluctuations that may damage the flower buds, excessive nitrogen levels from lawn fertilizers, improper pruning or a genetic weakness for flowering.

Q: I bought roselike begonias that won’t stop flowering. I am worried about what will happen to them this winter. What can I do to save them? (Britain)

A: Bring them inside before the weather gets too cold and treat them as houseplants. Supplemental lighting may be needed to maintain them through the dark months of winter in Britain.

Q: I use quite a bit of insecticidal soap to keep the bugs at bay on my plants. The stuff is expensive, so I have been looking into making my own. I have found some recipes online. Some call for Dawn dish soap, but other Web sites say that using it may cause a burn on tender plants. I'm confused! Do you have a recipe? (e-mail reference)

A: Insecticidal soaps are expensive to use on a regular basis. Attempts have been made by gardeners all over the world to find an acceptable substitute. When I worked for a rose-growing company as a propagator back in the dark ages in Newark, N.Y., we used a Dawn detergent liquid formulation that didn't damage mums or other cuttings. It did an acceptable job of controlling common soft-bodied insects, such as whiteflies and aphids. Being in a greenhouse situation where we were all working shoulder to shoulder and the plants were equally as crowded, we couldn't afford to use anything toxic to us or the plants. Put 1.5 teaspoons of Dawn in a quart of water. Our greenhouse was shaded with cloth and cooled with swamp coolers, so the cuttings never were held back because of heat stress. It worked, but a word of caution. What kills the insects, dehydration from loss of cuticle, also has the potential to damage plants for the same reason. Test the formulation out on a nonconspicuous part of the plant to see if any damage occurs. If none, then use it as needed during the cooler part of the day. For scale insects, take a cup of isopropyl alcohol and add 1 teaspoon of Dawn to it. Mix this with a quart of water. Again, test the formula on a small area before using it on the entire plant. This has been found to be very effective in controlling these very tough insects. Your results may vary, so heed my cautions before jumping into this with both feet!

Q: I have a white flowering dogwood tree. The tree gets morning and evening sun. I planted it about three years ago and it's doing well. I would like to transplant this tree to an area that only gets morning sun. When is the best time to transplant the tree and what should I be concerned about during and after transplanting? (e-mail reference)

A: My first suggestion is to not transplant the tree if you don't need to. That said, the best time to transplant is in early spring while the plant is dormant. Get the hole dug at the new site first. Keep as much of the rootball as possible when digging up the tree. Plant the tree at its new location at the same depth as the old. Transplant the tree on a cool, cloudy day or going into the cooler evening hours. Water the plant about 48 hours before moving and water the hole at the new site before moving the plant. Give the plant a good soaking after transplanting and keep it moist, but not soggy.

Q: I have a flowering crab that has been attacked by bagworms! My dad told me to let it be, but I worry that I will lose the tree. What should I do? (e-mail reference)

A: You never want to ignore a bagworm infestation. During the winter, pick off and destroy as many of the bags as possible to reduce the number of eggs. Next year, depending on where you live, spray between May and July. Use Bt (Bacillus thuringiensis), Orthene or Sevin insecticide. The Bt is best because it will not harm anything else. If the damage continues after spraying, reapply again in two weeks.

Q: I did not get any blossoms on my apple trees this year. However, we did have an early frost. What would cause the trees not to blossom? (e-mail reference)

A: Severe low temperatures during the late winter months could kill the flower blossoms. Overfertilizing also may have kept the tree in a vegetative state.

NDSU Agriculture Communication

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