Yard and Garden: May 22, 2015

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This is the Q&A for the Yard and Garden show for May 15, 2015. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2015. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Kevin Korus, Diagnostician for the UNL Plant & Pest Diagnostic Lab

1. A caller with a river birch that is 5-6 years old was planted with 3 trunks and now it has 5 trunks. Should those be removed or will it harm the tree?

A: River birch trees are commonly grown as a multi-trunked tree. If additional trunks appear, they can be left on or cut off with no problems for the tree, as long as they don’t grow too large before they are removed. If the trunks to be removed have grown to be 1/3 of the tree or more or the trunks are 1/2 the size or larger than the main trunk, you would not want to remove these as that would be removing too much of the tree in one growing season and can cause more problems to the tree than benefits. If they are not in the way, I would suggest leaving all 5 trunks.

2. A gentleman wanted to know how and when to prune blackberries and raspberries. He has raspberries that have died from the top downward on some branches with green growth at the base of the plant. What should he do about this?

A: The top dieback would likely be due to water stress or winterkill which occurs during the winter months when we see little moisture. As for general pruning, there is a great guide from the University of Missouri Extension to describe the many practices of pruning brambles, Pruning Raspberries, Blackberries, Gooseberries, Currants, and Elderberries.

3. This caller has amaryllis bulbs that were growing great and now the leaves are starting to turn yellow. What is the cause of this and how can she stop it from happening?

A: This plant is likely in need of a fertilizer treatment. They should receive regular fertilization with a houseplant fertilizer. Also make sure that the plant isn’t sitting in water. Amaryllis plants should be watered when the top two inches of soil are dry to the touch.

4. This caller has Weigela ‘Wine and Roses’ that she had trimmed last fall. Now one of them is only greening up at the bottom of the plant, why is this?

A: This plant is suffering from winterkill. As long as the bottom is greening up, the plant should be fine. Those dead branches can be removed back to green growth or back to the ground if there is no green on the branch at all. Remember to keep plants watered on the warm days when we face a dry winter like we did last year.

5. This caller was curious about rhubarb. How long in the year do you harvest rhubarb in the year or can you continue to harvest all year long? When should they be transplanted? What do you do when seed stalks appear on the plant?

A: You can harvest the plant until the plant begins to produce slender stalks. After that the plant needs to be left alone to replenish the sugars and nutrients to continue growing and produce next year. The stalks can be cut off or they can be pulled off. When the seed stalks appear on the plants, they should be removed. The production of seed stalks takes energy from the plant to make the seeds rather than leaving it to produce leaves and the stalks. Transplanting rhubarb is best done in the spring of the year. Avoid harvesting for the first growing season after transplanting and only do light harvest in the second season. By the third season, harvest can resume as normal. This is to allow the plant to get a good root system developed before loosing much of its leaf area.

6. This caller has a pin oak tree that is 45 years old. He added a mulch ring to the tree recently and wanted to know if rock mulch or wood chip mulch is better for the tree?

A: Any mulch is better than no mulch. Wood chip mulches keep the roots cooler and hold in more moisture than the rock mulches, but the rock mulches will not blow away or need to be replenished each year like the wood chip mulches. Either way keep the mulch only 2-3 inches deep.

7. This caller wanted to know how far apart to plant her asparagus? She planted hers 1.5 feet apart, is this too far apart?

A: Asparagus should be about 6-8 inches deep and 12-18 inches apart. There isn’t a problem with planting it too far apart, the problem would occur if they are planted too close together. Plants not spaced correctly can lead to disease problems.

Yard and Garden: April 24, 2015

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This is the Q&A for the Yard and Garden show for April 24, 2015. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2015. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Jeff Culbertson, Assistant Director of UNL Landscape Services

1. This caller wants to know why the water in her rain barrels is turning green and how to fix that problem?

A: The water should be used sooner from the rain barrels and not allowed to sit in it for very long periods of time. There is a great NebGuide on ‘Rainwater Harvesting with Rain Barrels‘. Algae can sometimes appear and can be reduced by:

  • Limit nutrient build-up in the barrel by reducing the amount of sediment and plant debris entering the barrel. These are sources of nutrients like phosphorous and nitrogen that promote algae. Clean roof gutters at least annually. If hosing out the roof gutter, remove the rain barrel before cleaning. Consider installing gutter screens along with using screens/filters before the barrel inlet.
  • Clean the barrel at least once a year to remove sediment.
  • Use dark-colored, painted, or opaque barrels to limit light.
  • Place rain barrels in a shady location when possible.

2. This caller had a willow that is leafing out from the bottom without any growth at the top of the tree. Is this normal or what is wrong with the tree?

A: This could be due to dieback from the winter which is being seen throughout the landscape this year. It is still early in the season so the tree could come out of it, so give it time to see if it comes back. Scrape off some of the bark with your fingernail to see if underneath is brown or green. Green is healthy growing tissue, brown is not. If it seems to be dead later in the season, you can prune out some of the dead branches and the tree may still survive.

3. When is the best time to dig cedar trees from the pasture to transplant them into a windbreak?

A: Now would be a good time to do this. Make sure they are small trees and that they are protected from deer and rabbits in their new location. Keep them well watered.

4. What is a good rhubarb fertilizer?

A: 12-12-12 or 10-10-10 would be a good general fertilizer to use or manure in the fall.

5. This caller wanted to know if Ponderosa Pine was still a recommended tree due to the threat from Pine wilt?

A: Ponderosa Pine is only mildly affected by pine wilt. Very few ponderosa pines have been killed due to the disease. It is still on the list of trees from ReTree Nebraska. Watch these trees for tip and needle blight, 2 common needle diseases, that can be easily treated with fungicides.

6. A caller has 2 trees in her windbreak that were planted about 8 years prior to a storm that has caused them to lean now. It has been a couple of years since the storm, but the trees are still leaning. Can this lean be fixed?

A: They will grow straighter over time and eventually straighten up somewhat. If the lean is too much, they will not overcome that.

7. This caller has been gradually replacing a plum hedge with Lilacs. What can he do to prevent disease and insect problems in the lilacs?

A: After about 2-3 years of initial growth, begin annually removing the largest, woodiest stems from the lilac shrubs. This will help keep the shrubs with younger, better producing wood and it will help keep the borers and scale away from the plants. As for disease control, just be sure to space the lilacs properly. Most full sized lilacs will get 3-4 feet wide so space them about 4 feet apart to reduce the overlapping of the branches and leaves which can lead to more disease problems.

8. A caller has a large asparagus bed that wasn’t cleaned up last fall. What care can be done for the asparagus now and in the future?

A: It would be best to clean the asparagus up one time a year, either in the fall or late winter just before spring growth begins. To help reduce weeds after that, spray the weeds while they are green and the asparagus hasn’t emerged for the year yet in the spring. Fertilize the planting bed either in the spring with general purpose fertilizer or in the fall with manure or both times.

9. This caller has a rose bush on an old property and wants to know how to propagate it or transplant some of it to their home?

A: Remove and transplant any suckers on the plant will work on an older rose variety that wouldn’t have been grafted. Anytime now is a great time to transplant a rose bush.

10. This gentleman has French Dwarf Lilacs and he was told not to trim them out. Is this true?

A: These can be cut back or caned out annually to keep them smaller and to help them produce more flowers.

11. A caller had stumps from trees that were cut down last year. The stumps were treated with Tordon. Can he use the mulch they will make from the stumps in his landscape or would the Tordon still be in the wood chips?

A: Wood chips that were treated with Tordon could still have that pesticide residue in the wood chips. It should not be used around plants. Disclaimer: Tordon should NOT be used in a landscape setting, it is against label instructions. Always read and follow pesticide labels. Remember: The label is the Law.

2015-04-15 11.03.06

12. This gentleman had cedars with the tips of the branches turning brown this year. What is causing that and what should be done for it?

A: This could be winter kill as that is showing up in many juniper species this spring. It may also be Kabatina, a disease of junipers. The brown can be cut out of the trees at a branch crotch. The trees should live.

13. This caller was looking for a shade tree for her front yard that is fast growing, stays around 20 feet tall and possibly provides flowers or good color to the landscape.

A: Chanticleer or Cleveland Select Pear would be good for spring color. Crabapples can also grow to 20 feet tall and would provide a great deal of color and scent in the spring. Japanese Tree Lilac is another good choice for a smaller tree.

14. This caller is planting strawberries and raspberries. What kind of care would she need to provide them?

A: Here is a good guide from Sarah Browning on Summer Berries-Raspberry and Blackberry to guide you through the raspberries. Heritage is a good raspberry variety choice. This is a good guide from Lancaster County Extension on strawberry care called Growing Strawberries.

15. This caller has a pin oak tree that has iron deficiency. She has used the iron plugs on the trees but she is curious if there is another choice that will work better and for a longer period of time on the pin oaks?

A: This tree will continue to have problems once it starts to show signs from Iron Deficiency and it will eventually die from this nutrient problem. She can try to have a professional due trunk injections which will last longer each time, but this will have to be continued for the remainder of this trees life.

16. This caller wanted to know how to prepare cut lilac flowers to last longer indoors?

A: Cut the flowers before they have opened on the plant. Make a new cut on the stem and change the water daily. Use a preservative in the water. The preservative can be either a store bought product or make your own mixture by dissolving 4 heaping teaspoons of cane sugar and 2 tablespoons of white distilled vinegar in one quart of warm water.

17. This caller wanted to control the dandelions in his yard and not the clover. Can a chemical be used for this?

A: Using spot sprays of 2,4-D when the weather is calm and the temperatures are below 80 degrees Fahrenheit for the day of application and the 2 days following would help reduce damage to the clover. The other option would be to dig or hand pull the dandelions. The chemicals that would work for dandelion would also work to kill clover.

Happy Arbor Day! Plant a Tree!!

Image Courtesy of Steven Katovich, USDA Forest Service, Bugwood.org
Image Courtesy of Steven Katovich, USDA Forest Service, Bugwood.org