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Published July 01, 2011, 12:00 AM

Hortiscope: Raspberries could have fertilization issue

Q: I planted my raspberry plant in the spring last year, but I do not remember the variety. I live in southern California. It flowered last year and again this year. I do have fruits that formed, but they look like they are incomplete. Why is this happening? Do I need to fertilize it with 5-10-5 fertilizer?

By: Don Kinzler, INFORUM

Q: I planted my raspberry plant in the spring last year, but I do not remember the variety. I live in southern California. It flowered last year and again this year. I do have fruits that formed, but they look like they are incomplete. Why is this happening? Do I need to fertilize it with 5-10-5 fertilizer? Does the fertilizer have to be marked for raspberries? Do I need to cut the canes back during a certain season? (email reference)

A: This could be from incomplete fertilization of the flower or from lygus bug damage when the plants were in flower. I know something about growing raspberries in North Dakota, but your problems need to be addressed by an Extension agent in your area. To find one, go to http://ucanr.org/County_Offices.


Q: I live in Connecticut. Last summer, I bought a small hibiscus tree that I keep potted. It did fabulously the whole summer, and I brought it inside during the winter. Through the winter, I kept it by a sunny window and watered it enough so the roots wouldn’t go dry. During the winter months, most of the leaves dropped, but the plant stayed alive. When spring came around, I started bringing it outside during the day whenever the temperatures got above 60 degrees. The plant liked it because the leaves came back, and I was getting a few blooms. Unfortunately, one night it was left outside, and the temperatures dropped to 35 to 40 degrees. It did not like that. Some of the leaves dropped, and it never bloomed again. Once the weather got warmer and it was able to spend all its time outside, the leaves came back, but still no blooms. I have fed it 10-10-10 fertilizer a few times. I don’t know what else to do. How can I help my hibiscus plant be happy and bloom again? I have enclosed a picture so you can see what it looks like. (email reference)

A: Be patient. It will get around to blooming sometime this summer. Don’t fertilize, because it isn’t needed for the rest of the season unless the foliage starts to yellow from nutrient deficiencies. With the summer weather being a little more consistently dependable, it should put out generous new growth and flowers sometime in July.


Q: I have a harcot and two harogem apricot trees that are bearing fruit this year, but some of the fruit seems to have sap oozing from it. I used to spray the trees with Agway Orchard Spray before the blooms came out. Since then, I have been reluctant to do that because the orchard spray isn’t for apricots. I sprayed with Malathion once, but we lost some fruit off the trees after we did that. I’ve been looking for what pest control to use. All I could find was to spray Sevin on the trunks for peach borer problems. Any suggestions would be greatly appreciated. (email reference)

A: At this point, it is too late to do much in the way of spraying. I would pick the fruit that is showing the oozing and dispose of it as soon as possible. I suggest basic sanitation to start with to control this maggot infestation.

Remove all mummified fruit on the tree or ground before winter arrives. Spray the trees with a dormant oil prior to bud break next spring. Get pheromone traps at a local garden center to capture plum curculios, which I think are attacking your apricot trees. Do it right after the trees are sprayed with the dormant spray but before the flowers open. Just as the last petals from the flowers are dropping, spray with Sevin insecticide. Be sure to follow label directions.


Q: Most of my strawberry patch has fruit that is green and hard and has discolored seeds. The fruit stems seem reddish and shriveled. There are no insects in evidence. I suspect drifting from a farmer’s Roundup application on a cornfield. Is that possible? (email reference)

A: Anything is possible. However, what you are describing doesn’t sound like the typical symptoms of Roundup injury. It sounds more like lygus bugs, which are about the size of a period at the end of a sentence. These bugs scurry around and feed on the blossoms, fruit and foliage.


Q: We live in a semirural area of southwestern Washington state. Deer have been an off-and-on problem for me through the years. However, during the past 30 years, I’ve noticed a cycle and taken advantage of it. I’ll begin with the rabbits. We will get a bunny bloom every four to five years. With so many rabbits, we soon have cougars, bobcats and an occasional black bear wander in.

It doesn’t take long for the bunnies to disappear. I’ve also noticed that the deer stay away for a year or two after the cats do their bunny shopping. I am thinking about putting this to work for me by calling the local zoo and seeing if it will give me some scat from the cougar and bobcat displays. I would deposit it around the perimeter of my property. Do you know if this idea or anything similar has been tried? If so, what was the outcome? (email reference)

A: This is some very astute observing on your part. Yes, it works. However, you cannot apply it once and forget about it. An annual (at least) application is needed. Cougar, bear and wolf urine (don’t ask how they collect it) is marketed for just the purpose you describe. If you can coax the zoo to provide some of the liquid as well, that would be another deterrent to help keep deer away.


Q: I had a producer bring in a sweet corn kernel that he planted a few weeks ago. The kernel had larva inside. Is there anything he can do to control the problem? (email reference)

A: The problem is seed corn maggot. If the problem keeps happening, it necessitates the use of corn seed that is treated with an insecticide coating.

Seed corn maggots spend the winter as larva inside a “wheat seedlike” puparium in the soil. When mature, the maggot pupates inside this dark brown structure.

First-generation adults emerge in April and May. They mate and then lay eggs on moist soil high in organic matter or near decaying vegetation. The adult resembles a small housefly. It is gray to brown and about 1/5 inch long. It can be seen flying over freshly worked soil or where manure has been spread. Seed corn maggot eggs hatch a few days after being laid and begin to burrow into and feed on the seeds. The maggots usually feed for two to three weeks before changing into the brown pupal stage. Pupae do not damage plants or seeds. Adults emerge from the pupal case in seven to 14 days and then mate to begin a new cycle. The entire lifecycle may require no more than 21 days, which results in three or more generations each year. Later generations are of little to no economic importance to corn. Because of this abbreviated life cycle, it is very likely too late to do anything about this pest now. When seeding corn in the future, the producer should use stock that has been treated with an insecticide.


Q: I just purchased a Robinson crabapple. It is 10 to 15 feet tall with small leaves and branches growing out of the trunk in various spots. It has areas without any leaves or starting branches. Should I cut the tree down somewhat so it grows wider or will it do this naturally? (email reference)

A: The first year, leave every bit of leaf area on the tree. Every leaf is making carbs for the roots to expand and grow into the surrounding soil to mine the elements needed for more vegetative growth. Next spring, you can begin the process of carefully pruning the tree to become the shape you want.


Q: I have two fern peonies. I would like to know how to remove the seeds and how to prepare them for planting. (email reference)

A: Keep in mind that the seeds you collect and the resulting seedlings will not be the same as the parent plant. To keep the same characteristics of the parent, you need to do asexual propagation. Germinating peony seeds (herbaceous or tree) is a must for anyone interested in breeding peonies. It also can be a rather interesting exercise because of the double dormancy of peony seeds. Collect the seeds as soon as the pods begin to open. The harder the outer shell, the longer the first dormancy period. Place the seeds in sealed plastic bags with some barely moist vermiculite or soilless germination mix. Place the sealed bags in a warm area of the house (not in the sun) and check them every week to see if the roots have emerged and to make sure they are moist. Leave them in the warmth until the roots appear, which can take anywhere from a few weeks to several months. Once the roots appear and are about an inch in length, move the bag to a cool location. The temperature should be around 40 degrees. Leave them in the cold for 10 to 12 weeks. Check them regularly to see if the embryonic shoots have emerged. When they do, pot them in potting soil immediately and place them in a sunny or well-lit spot. They should be at about 70-plus degrees for continued growth.


Q: I bought six weigela plants three years ago. I live in western Pennsylvania.

During the winters, they turn into brown sticks. In the spring, they come back and grow nicely. Is it normal for weigela plants to start over every spring?

What does a mature plant look like during the winter months? Should I do something to protect them during the winter? (email reference)

A: I used to live in the Pittsburgh area. Every weigela I saw went through the same process. You have to go farther south to have them not become dead sticks during the winter months. Be thankful they come back every spring!


To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or email ronald.smith@ndsu.edu.

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