February 12, 2004

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: My cat has started to use one of my houseplants as a litter box. As far as I can tell he has only urinated in it. I have managed to cover the soil and that seems to be keeping him away from it, but the plant is not doing well. The plant was dropping leaves at an alarming rate, which has slowed but the leaves that remain are very droopy. Is there anything I can add to the soil to counter the effects of the urine? (E-mail reference)

A: The best and quickest treatment for animal urine removal is to leach the container three times with fresh water. The plant is probably suffering salt toxicity from the animal's urine. The fresh water will effectively remove the toxic salts.

Q: My Grandmother gave me a jade plant when I visited her last summer. I placed Ella (named after my Grandmother) in my window. The plant was growing well even though I just recently found out that you're not supposed to water as frequently as I have been. I repotted the plant but before I did, I checked for rot damage. Sure enough the roots where drenched and almost rotted. I also found a few worms digging their way up towards the roots. I cut the soggy root, shook the dirt off where the worms were and let the roots dry out for a few hours before replanting it. I replanted using new soil and a slightly larger pot. I placed it back in the window. It's now very cold here and the heater is on which is also by the window but not close to the plant. Everything was fine and there almost appeared to be signs of new growth but lately the leaves have become very weak and are falling off. The tops of some of the lower branches are shriveling up and falling over and just recently the top of a branch twisted and fell off. Please help me save this plant. (E-mail reference)

A: I’m afraid your actions are killing the jade. Try and find any firm, solid plant tissue and cut it off for propagation purposes. Insert the tissue into a sand/peat mix (50/50) to root. You can use leaves or stems with leaves on them. The stems should be about 6 inches long. Your plant has most likely developed a pythium rot that is caused by cold, wet soil and overhead watering. Once it gets started it is difficult to control and often kills the plant.

Q: I read oak trees have long taproots that keep them from blowing over. How long are they, especially in relation to the size of the tree? Is this straight-down root unusual for a tree? I know the Bible talks about oak trees when speaking of something strong or long- lived. What sets them apart from other tree species? (E-mail reference)

A: Oaks (Quercus spp.) live a long time, are generally large trees and because of the extensive taproot system, have the distinctive characteristic of generally being quite drought hardy. The root system usually exceeds the volume of the branching system and like roots everywhere, will follow the path of least resistance and go where there is a balance of air and water. Oaks produce male and female flowers (staminate and pistillate) on the same tree in early spring. The male flowers are conspicuous and drooping while the female flowers are inconspicuous and held close to the leaf axils. From these flowers of course, arise the acorns, which are sources of food for animals. The acorns were also sources of food for Native Americans and early settlers. Oaks are divided into two distinct groups, often easily recognized by the foliage. Red oaks have sharp, bristled lobes with acorns that take two seasons to mature. White oaks have leaves that are rounded lobes, but never bristle tipped. Their acorns mature in just one growing season, making them tastier for those who choose to eat them. The bark on the red oak is dark and furrowed, while the white oak is typically grayish and scaly. That oaks are enduring and strong is without question. Oak trees can live for more than 100 years even if they are stressed by mankind's follies. Most oak species are found in the northern regions of the country.

Q: Do you have any information on why boxelder has red/pink streaking? (E-mail reference)

A: It is my understanding that the coloration is caused by a fungus that is brought to the tree by a beetle. Sorry I don't know more.

Q: I removed two Lombardy poplar trees this fall and I wonder what you would recommend for replacement? Which is the better evergreen, the Blackhills spruce or the Ponderosa pine? (Garrison, N.D.)

A: Try to locate either the upright European Aspen or the tower poplar as a substitute. As far as the evergreens, you can't go wrong with either. Both are native to North Dakota.

Q: I planted my muskmelons next to my cucumbers last spring. The cucumbers tasted very good despite the fact that we had no rain after July 3 and I couldn’t water them. On the other hand, my muskmelons did not taste very good. Someone told me that the muskmelons could have crossed with the cucumbers because they have a similar seed and that's why the muskmelons did not taste good. Is it possible for muskmelons to cross with cucumbers? (Center, N.D.)

A: No, not with the initial planting and subsequent fruit set. Melons just don’t like the dry conditions.

Q: Why do potatoes turn green? (Tioga, N.D.)

A: Potatoes turn green because light reaches them. The soil covering must be porous enough for this to happen. You should not eat green potatoes.

Q: I have grown English ivy plants for several years. In summer I put the plant outdoors and in winter I have them in the living room. What causes rot on the leaves? Sometimes the rot will cover half the leaf. I don't over-water. I fertilize the plant on occasion with MiracleGro. (Tioga, N.D.)

A: What you are calling rot could be salt damage or poor to no drainage in the container. I suspect the water may be high in salts. Try watering with distilled water to see if that helps. Make certain the container drainage is good.

Q: I am writing to you regarding an amaryllis flower. I planted it according to the instructions on the box. When the leaves withered I allowed the bulb to rest and go dormant. The instructions said to stop watering and store the bulb, pot and all, away from light in a cool, dry area. The following season I repotted the bulb using fresh soil. However, it is now January and it has not started to grow. I watered it well when I planted it, yet the old leaves that show still look green but don't grow. Can you tell me what I did wrong with this plant? (Milnor, N.D.)

A: You may have kept it too moist during the rest period. Allow it to dry until the foliage loses color. Then let it sit that way, barely watering it once a month, for two to three months. At the end of that period, water normally to encourage new growth. If this doesn't work, dump it and get a new one.

Q: My sister has a braeburn apple tree. The seed sprouted in an apple so she planted them. To her surprise three grew. They are now about three feet tall and she is wondering if she should prune them and how. If she plants them outside will they survive? She lives near Churches Ferry. How and when should she feed them? (Dazey, N.D.)

A: You sister made a basic mistake of sowing the seed too early. Chances are the trees will not survive. Apple trees need full sunlight to grow normally and there is no way those trees are getting anything close to that inside the house. The cell tissue will be thin-walled and the entire plant very tender to any environmental extremes, which we get plenty of in North Dakota! She should get plant lights and direct them at the seedlings for about 13 hours a day. Don't fertilize or over-water. This spring she should play the move-out, move-in game in an attempt to harden them without killing them. Assuming that strategy is successful, she should plant the tree, container and all. Then when the tree defoliates in the fall, remove it from the container and replant. The tree will survive if she is very lucky. The bad news continues however because the braeburn apple is very likely not hardy enough for our region and will winterkill anyway. Sorry!

Q: I have an apple tree problem. The trees are 5 years old. They are colonnade apple trees or pole trees. I have five varieties; maypole crabapple, emerald spire, crimson spire, ultra spire and scarlet spire. They grew to be beautiful trees, but only the crabapple tree bloomed and grew a few apples. The other trees have not bloomed. I have pruned them but not a lot. The trees are now about 15 feet tall. I don't know if I should trim them or not to make them bloom. (Miller, S.D.)

A: It takes about five to seven years for many apple trees to set fruit to any great extent. You might try pushing a spade into the ground to sever some of the roots, but don't overdo it. If it works, you'll see the results in 2005, not this year.

Q: What is wrong with my plants? There are white specks on my azalea plants. Could the specks be bugs? Other leaves are turning brown and so are the leaves on my peace lily. Could it be the new potting soil? Am I watering too much? (Marion, N.D.)

A: It appears that the plants are being overwatered. As long as your potting soil and container are draining freely, the soil shouldn’t be a problem. Allow the soil to dry between waterings and dump any excess from the saucer after 20 to 30 minutes.

Q: Where did the flies come from that invaded my attic this fall and winter? They were never around until about a year or two ago. They are dark gray with white spots and like to live in windows or in a bright area. How do they get in and why are they alive in winter? How do I control them or prevent them from hatching? Where do they live and produce in the summer? (Jamestown, N.D.)

A: These pests are known as cluster flies, which could be any number of species. I am enclosing a publication written by Jeffery Hahn, entomologist at the University of Minnesota. Most likely you will have to employ a professional exterminator to get effective control.

Q: I have a question about my aloe vera plant that I am sure you can answer. I’ve had an aloe vera plant for several years. I put it in a larger pot a while back to give the roots more space. The spikes usually grow straight up, but on my plant only a few point upwards and the rest curve out over the edge of the pot then downward. Some are actually touching the table the plant is sitting on. Why don't they all grow upwards? (Detroit Lakes, Minn.)

A: That is simply the morphological characteristic of the plant. Every plant has a basic morphological form as it grows, develops and matures. With your aloe vera, the drooping foliage is a characteristic of maturity.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu

North Dakota State University
NDSU Agriculture Communication
NDSU Extension Service
ND Agricultural Experiment Station