Questions on: Orange
Ron Smith, Horticulturist, NDSU Extension Service
Q: My husband has a dwarf orange tree, but it never has bloomed. He waters it almost every day. The tree is pretty and has plenty of leaves, but he is concerned about the blooming. The tree was purchased in Florida and we have had the tree for two years. Thank you for your assistance. (e-mail reference)
A: The orange tree will bloom when it matures enough to do so. This could take up to five years. In the meantime, enjoy the fact that you have a healthy, beautiful tree to enjoy. It will surprise you someday with beautiful, fragrant flowers.
Q: I have a small orange tree in a pot. It is covered with small, reddish brown circular spots that can be wiped off easily. What sort of pest is this? The oranges the tree produces are green, not orange. Could this be related to the pest? (e-mail reference)
A: Those spots sound like scale insects, so keep wiping them off. As far as the oranges, you probably have a species that requires coloration through ethylene gas. This can be accomplished by harvesting mature, but green oranges and placing them in a bag of apples. Apples are good producers of ethylene. Do this at room temperature and the oranges should turn color in a few days.
Q: I have a miniature orange tree that I have had for three years. When I bought the tree, it had oranges. Since then, it has not produced any new oranges. The tree has grown, flourished and occasionally flowers, but has not produced oranges. After flowering, there are tiny green buds, but then they fall off. Will my tree ever produce oranges again? (e-mail reference)
A: Try a little tree doctoring when it is in flower. Snap the branches with your index finger to shake the pollen onto the pistil. It sounds like the flowers are not getting fertilized so the fruit cannot develop. This should correct the problem.
Q: Last year I planted scarlet nantes (on seed tape) and sweet sunshine (sample from seed company). I harvested two oranges of good quality. The rest were yellow, fibrous (not woody, more stringy) and had no flavor. What went wrong? I wonder if the cause was environmental because I used two different varieties. The site is sunny with a raised bed. (E-mail reference)
A: There are a number of possible causes such as too much nitrogen, composting or gardening with fresh manure, water-logged soil, too low a temperature at the time of germination, compacted stony soil or it could be from the feeding activity of the carrot fly larvae. The most likely cause is a disease known as Aster Yellows, which is spread by leafhoppers.
Q: Our daughter gave us an 18-inch miniature orange tree in 2001. After being on the deck all summer, where it grew about 6 inches, I brought it in to our sun room. Today it is about 4 feet tall and looks good, except for the fact that it should be trimmed back. Any suggestions? (Aberdeen, S.D.)
A: The only reason I know anything about orange trees is that I lived in areas of the country where they grow -- Texas and Arizona. Prune them to open the crown for good light penetration and air circulation, making cuts back to lateral branches or the main trunk. Do not leave any stubs. Prune out anything that is growing back into the center of the tree's crown, where branch angles are V-shaped and, of course, anything that is diseased or damaged. Enjoy and good luck!
A: The problem is that you have selected a seed, or "pip" as they are sometimes known, from a plant that was bred to bear fruit in the miniature form. It will eventually bear fruit, but it will do so only when it gets large enough. This is the problem with sexual (seed) propagation from a hybrid. To perpetuate the dwarf fruit-bearing size you must take a cutting and root it.
A: Those little white bugs could be mealy bugs, or some other critter that is up to no good. I suggest repotting in pasteurized soil, washing the roots carefully, along with the container. In fact, I would suggest immersing the container in a 10 percent chlorine bleach solution for a few minutes to make sure everything is clean or dead. Check the undersides of the leaves as well, and clean them with a damp cloth. Insecticidal soap will go a long way toward keeping many of the soft-bodied insects at bay.
Q: I am not a gardener as I live in an apartment, but I do have a few indoor plants. About eight years ago I brought home from Florida a miniature orange tree that bears fruit about the size of a walnut. I have had good luck with the tree indoors, and it has produced as many as 100 oranges in one season. Two years ago I cut it back rather severely because it was getting too big, and this year it again had 96 oranges. It measures about 30 inches tall by about 30 inches across. I have started more than a dozen new trees from the seeds taken from an orange, but none of them would bear fruit. (Fargo, N.D.)
A: Generally, fruit trees--especially citrus trees--will not bear fruit until they are mature. This means that your trees are enjoying an extended juvenility before settling down and bearing a "family" of fruit. You can hasten this maturing process by not being so good to the trees. Hold back on the fertilizer and water a little, and keep the trees in the same pots to encourage root binding. A couple of months of this benign maltreatment should get those juveniles to produce some fruit.
Q. I have enclosed two leaves from a hibiscus I found baking in the August sun outside
the local al-Mart last summer. It looked bushy and healthy in the sun (if a little
windburned), but bringing it into my air-conditioned home, it promptly shed at least half
of its leaves. I thought this might be its natural fall pattern, but I eventually had to
prune back some of the bare stems so it didn't look so gangly. I also noticed some shiny
spots below the new growth that finally appeared and associated these spots with what
looked like pollen that previously fell from the flowers. Now this "pollen" is
appearing all over the plant, but is most concentrated on the new growth. I sprayed the
entire plant with soapy water, thinking I had some infestation, but the syndrome
continued. I also tried some mild
insecticide while it was still warm enough to do outside. No change. Please give me some clues to cure or clue too relax. The plant still looks healthy and other plants around it don't seem to be affected...yet.
Thank you for your advice last fall on my orange tree seedlings' browning leaves. Sure enough, watering them with non-softened water made the difference, and the mother tree is again producing lots of oranges. (Jamestown, N.D.)
A. Nothing to worry about! In close examination, I found salt crystal deposits in those "shiny spots," from either your water source or too much fertilizer.
If the plant is in a water-tight container or pot, this could cause salt accumulation to take place as well.
Q. I have enclosed leaves from a Calamondin orange, one of 96 seedlings started from the seeds of a plant I purchased. Please advise me about the brown edges. Only a few seedlings show this and otherwise appear healthy. Thank you. (Jamestown, N.D.)
A. Root or salt problems. The plants showing these symptoms are either in anaerobic soil conditions or the fertilizer salts are too high. Either condition could cause this problem.
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