March 9, 2000
Ron Smith, Extension Horticulturist
North Dakota State University
Q: When does sunscald occur on shrubs such as blueberries, Saskatoons and currants? What can we do to protect the plants from this damage? Also, what can you tell me about what and when to spray to keep currants etc. from having worms in them? (Westhope, N.D., e-mail)
A: These shrubs are generally not prone to sunscald, which usually occurs on thin-barked trees such as apples or pears when they are young, and on the southwest side of the tree. Protection is generally achieved by painting with whitewash or wrapping the trunk with cloth. It occurs when the sun hits the dark colored bark and raises the temperature at that location to 50 F or 60 F or higher--and the air temperature is still below freezing. When the sun goes down, the cell tissue ruptures at that site and sunscald occurs.
As for your insect question, spray with Sevin when the shrubs are in flower. Keep in mind that Sevin is toxic to bees, so spray at a time when they are not active--either in the early morning or evening. Spray again right after blossom drop.
Q: When a granular form of fertilizer or nitrogen is added to an existing flower garden, do you just sprinkle it on the surface and water it in? Will the fertilizer eventually trickle down to those roots, or do I need to do something different around those plants? I want to be sure that all my flowers get what they need as not all have done so well the last year or two.
Also, do I need to apply the nitrogen more than once a summer?
One more question! I often read about how many gardeners are always incorporating organic matter into the soil. I add peat moss to my soil whenever I plant new plants, but how does one incorporate organic matter around existing plants? If I dig around the plants do I risk damaging roots? Is it good enough just to spread the organic matter across the surface? (e-mail)
A: Nitrogen sprinkled on the soil surface as a granular fertilizer will move into the soil profile and become available to the roots with the irrigation water or rain. Of course, if the soil is as hard as concrete, it will simply wash off. If it has good tilth, it will work well.
During a normal growing season (whatever that may be!) it is a good idea to apply nitrogen-based fertilizer about once every four to six weeks, assuming you are going to water and care for the planting on a regular basis. I wouldn't go beyond Aug. 1, however, as it would mostly be wasted.
If you work organic matter into the soil away from the roots of the plants and simply spread it around the plants that are already established, that will benefit the plants and the soil greatly.
Q: I grow potatoes in my garden, and they are such a pretty plant, I have one growing in the house. It's only 2 weeks old and is 6 inches tall. I'd like to see if I can get it to produce. Will the blossoms need to be fanned to pollinate them? (e-mail)
A: Potato plants in the house? Now I've heard it all! You can fan them or simply give them some gentle shaking when (if!) they flower. Unless you plan to harvest the fruits of the potato and sow the seed inside, there is little objective in attempting to get them to set fruit. Keep in mind that these fruits are not edible, and their setting is not a prerequisite for the tubers to develop.
Q: We have bulbs of various early flowering plants in our yard. We are concerned that our unseasonably warm weather may activate them too early and that we might lose them when more seasonable weather and late frosts return later in March and April. Should they be covered with snow or chips to protect them or do we just take our chances. My wife thinks NDSU wasted a Ph.D. in botany on me 30 years ago because I don't know the answer. What do you think? (...about the bulbs only.) (Fargo, N.D., e-mail)
A: Nothing gained is ever wasted! The bulbs on the south exposure would be most vulnerable to early emergence. Keeping the soil cool with snow or straw mulch would slow their development down and keep them "hardened." Generally, the hardy bulbs grown in our area--tulips, daffodils, grape hyacinths etc.--make it through our capricious weather systems to only be done in by mice or rabbits. Daffodils are poisonous, so they are pretty much left alone, but the tulips are right at the top of the cottontail menu.
Q: I have had high water problems with my foundation which will necessitate excavating the outside as soon as the ground thaws. My problem is that most of my tulips are planted there. How can I save them? Can I transplant them into the garden with the plan of replanting them next fall?
Also, I have two small saguaro cacti growing in pots. They are several years old and are growing slowly. I haven't found a comprehensive guide to their care. Should they be repotted? How often? When should they be watered and how much? (Jamestown, N.D.)
A: Allow the tulips to emerge, then when excavation is necessary, remove and replant. If the foliage has not turned yellow yet, that is OK. So to answer your questions in a word: yes!
Saguaro cacti will stay small in a small container and get larger when placed in a larger one. Generally people keep them in the container size they are happiest with. They don't require much in fertilizer or water.
Q: Can you please tell us if the "sanseveria" plant would be commonly considered a succulent? We have a bet going and are wondering who is right. (e-mail)
A: Nope! They don't require much water, but their leaves are not water storage organs like the other succulents, which would include such plants as agave, aloe, kalanchoe and the cacti.
Now I have made someone happy and someone angry! I hope not much money was wagered.
Q: I own a gold mosaic houseplant and have it in my greenhouse. It was purchased the first week of February. When I brought it home the temperature was about 30 F. The leaves are curled up on the edges and some brown spots appeared. I stopped watering it as it is still moist. Are these symptoms due to a cold draft, the wrong temperature when the plant was purchased or too much water? (e-mail)
A: I'm sorry, but I don't know what a "gold mosaic" houseplant is. Do you have the botanical name? If you can give that to me or a more detailed description of what it looks like, I could give you the cultural requirements.
From the symptoms you describe, it sounds like the plant was troubled by the exposure to the cold draft when bringing it home, and then compounded by keeping it too moist. You are smart to back off on the watering. Allow it to dry between watering cycles. I often tell people who are troubled by their overwatering habits to wait 24 hours to water when the urge hits to water the plant!
Q: I bought a poinsettia for Christmas 1998 and put it in front of our south-facing picture window. It's had no repotting, no pruning, no special lighting. All I do is water it once in awhile with water from my goldfish tank.
The red began appearing just before Thanksgiving. It's good this plant decided to color up all on its own, because I'd never be organized enough to do the 12 hours of dark and light in the closet thing. Since we have cats, we cannot leave any doors shut in our house. They are much to nosey!
Maybe this plant had extrasensory perception and knew that I had planned on getting one of those pink mottled poinsettias this year and would have thrown the old one out. It colored up and I saved money and have had lots of enjoyment out of watching it grow and change. (Cooperstown, N.D.)
A: Thank you for the success story! Your house sounds like mine--giving in to the whims of the cats! We have four!
Q: My onions are starting to sprout. Can I use the sprouts just like you would green onions? Are potato sprouts poisonous? Can you eat them like any other type of sprout? (Stanley, N.D., e-mail)
A: Yes, the onion sprouts will be OK, but you can't eat the potato sprouts.
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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.
Source:
Ron Smith (701) 231-8161
ronsmith@ndsuext.nodak.edu
Editor:
Dean Hulse (701) 231-6136