Yard and Garden: July 14, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for July 14, 2017. 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 28, 2017. 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: Steve Karloff, District Forester from the Nebraska Forest Service

If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/44qr and be entered to win a free plant book or some free UNL gifts.

1.The first caller of the day has overgrown Forsythia and Yellow Dogwood plants. What can be done for pruning to reduce the unproductive plant materials and when can it be done?

A. Because these plants are overgrown, it would be most beneficial to do a rejuvenation cutting on them. A rejuvenation cutting is when you prune a shrub back to about 6-8 inches from ground level and remove the majority of the top growth. This will get rid of all the old, unproductive wood to bring in all new, younger wood that will be more productive to leaf out better throughout the entire shrub, will lead to more flowering, and will be healthier and free of insects and diseases that were problematic on the shrub. It is best to prune forsythia immediately after they flowered, but it could be done in the fall. Remember with a rejuvenation cutting that the plants will not flower for at least 2 years following the heavy pruning.

2. A caller has blue spruce trees planted in an area near a lake. Some of the spruces are 60 years old and some are 15 years old, all are dying from the bottom up. What is wrong with these trees?

A. Too much moisture can cause blue spruces to die from the bottom up, since they are planted close to a lake, they may be getting too much watering. When replacing the trees, choose a species more adapted to wet locations such as white pine, cedars, or bald cypress.

3. This caller has a green apple tree that was planted before he moved in and the apples are falling so they are ripe. The apples are not juicy and are quite porous and pithy. What is wrong with the apples?

A. After discussions on this with Paul Hay, this is just the variety of apple that is growing there. This is an apple that is used more for processing to be used in pies and sauces and not for fresh eating.

4. A caller has rabbits that are eating her hostas and lilies. What can be done to control them?

A. The only effective management for rabbits in a garden is to put up a fence that is at least 2 feet high.

5. This caller has a bur oak that was planted in the spring. The old leaves on the tree are turning brown but the new growth is green and healthy looking.

A. Be careful to not overwater a tree, especially with newly planted trees. These young trees have a small root system and do not need to be watered as heavily as an older, established tree. It is beneficial to allow the roots to dry out a little between waterings.

6. A caller has white pines that were planted too close to the driveway and now the branches hit cars when they come to park in the drive. Can the branches be trimmed back so they don’t hit cars and when can that be done?

A. Yes, these branches can be removed. Take the branch all the way back to the trunk so that they don’t regrow causing pruning to be necessary every couple of years. You can prune evergreens most any time of the year.

7. This caller has a bur oak that was planted last fall. It didn’t come out of dormancy this spring and has not grown. However, there are suckers coming up at the base of the tree, can the main tree be pruned out and the suckers allowed to grow into a new tree?

A. Yes, remove the main tree and allow one of the larger more upright suckers to grow into a new tree. However, sucker growth is not always as strong as the tree itself, so it may not perform how the tree was supposed to.

8. Can lilacs be pruned now?

A. No, it is best to prune lilacs within a couple of weeks after they are done blooming. Lilacs produce their flower buds in the summer and fall of the year before they bloom, so pruning now would cut off the flower buds for next spring. To ensure flowering for next year, wait until after it blooms next year and then prune it back at that time.

9. A caller has cypress trees that were planted 5 years ago. One of the 2 trees is in great condition with good color. However, the other one is smaller and yellow in color. The trees are only a few feet apart. What is wrong with it and can it be fixed?

A. The yellow and shorter tree may have just been a bad tree out of the gate. Sometimes our trees develop a problem in a nursery or from the seed source and never really overcome that. Also, with Bald Cypress trees, it is hard for them to overcome iron chlorosis. When these trees get iron chlorosis, they become stressed and no matter how many trunk injections, which also harm the tree, they never come out of the chlorosis. At this point, it would be best to remove and replace the bad tree.

 

Summer Patch at Christenson Field, P Hay

Photo of Summer Patch from Paul C. Hay, Nebraska Extension Educator

10. This caller is having problems with their lawn. He fertilized it in May but now it has brown patches throughout. How much water does a lawn need and how can he improve his lawn?

A. Our lawns need 1-1.5 inches of water per week on average to stay green and out of dormancy. The patches could be the lawn going dormant or they could be from a fungal disease. There are a lot of summer fungal diseases such as brown patch, summer patch, and dollar spot. They are common in the hot and humid days in late summer but as soon as that weather fades, the brown spots will turn green again. For more information on these diseases, see this TurfiNfo from UNL.

11. A caller has Bradford pears that have branches coming out 1.5 feet above the ground, should those be removed or will they move up as the tree grows? The trees also have suckers, what should be done about that?

A. If these low branches are in the way for mowing and you don’t like how low they are, they should be removed. Remember not to remove more than 1/4 of the tree in one season, so you may have to remove one this year and another next year. Those branches will always be at that level, though, so if they are in your way they need to be removed. As for suckers, cut those off at ground level and don’t treat them with anything or the spray will kill the tree as well.

12. This caller has pumpkins in his garden that are wilted during the day but at night they look fine. What is wrong with the plants?

A. If a plant looks better in the evening or in the morning but is wilted during the hot part of the day, it is heat or water stress. Make sure your plants are properly watered through this hot and humid couple of weeks of the summer.

13. A caller has tomato plants with leaves that are drying up from the bottom of the plant. The tomatoes are also rotten on one end of the fruit. What is causing these two problems?

A. Ensure that the plants are being properly watered. Vegetable gardens need 1-1.5 inches of water per week. Hand watering at the base of the plant every night is not sufficient for the root system. The plant could also be exhibiting early blight which is common right now. Remove the infected leaves, the disease will fade soon. The rotten side of the fruit is blossom end rot. This is a calcium deficiency in the plant caused by uneven watering making the calcium unavailable to the plant. Adding calcium to the soil will not help the problem, just make sure your plants are well watered and mulched in. Blossom end rot will fade soon. You can eat the good side of the fruit and dispose of the rotten end.

14. This caller has round berries on the plants of her potatoes. What are these?

A. These are the fruits of a potato plant. We typically do not see the fruits because we are growing the plants for the tubers produced underground and we harvest before the fruits appear. Remove the fruits so the plant can build the tubers.

15. A caller has roses that have uniformly round holes on the edges of the leaves and brown spots. He sprayed with rose spray and it is not working. What is wrong with the plants and how can he fix it?

A. This is likely damage caused by the leafcutter bee which is a pollinator and beneficial insect. There is no need to control this insect. Here is a great article from Jonathan Larson, Nebraska Extension Entomologist, on Leafcutter Bees.

16. How do you control puncturevine in a lawn?

A. Use a 2,4-D product in the pre-bloom stage. Management will not be achieved this time of year because the plant is large and will be difficult to kill. Also, don’t use 2,4-D products in the heat and humidity of the summer or the product may move to non-target plants causing damage.

17. How do you control moss in a pond?

A. Copper sulfate crystals can be used for control. For more information on pond management, visit the Lakes, Ponds, and Streams section of the water.unl.edu website.

18. A caller has apple trees that get insects in the fruit every year. When and what should they be spraying for that?

A. It would be best to get on a spray schedule, spraying with an orchard fruit tree spray every 10-14 days throughout the growing season. For more information visit the Local Food Production page within the food.unl.edu website for spray guides.

19. The last caller of the day has vines with milkweed type pods growing in his fenceline. What can be done to control it?

A. The plant sounds like honeyvine milkweed. At this point of the year, pull it or spray it with roundup. In the spring or fall, 2,4-D could be used, but not now due to the heat and humidity.

 

What’s that green beetle…

Green Beetles Blog post

All plants are wonderful. However, it is highly unlikely to find a plant that has absolutely no insect problems. This year we have been seeing a couple of unusual beetles wreaking havoc in our vegetable gardens and they can be found on our trees and shrubs as well. Japanese Beetles and Green June Beetles have been more problematic in southeastern Nebraska this year than most other years.

Japanese beetles are an invasive insect from Japan, where it is not a major pest due to the natural predators found there. This pest was first found in the United States in a New Jersey nursery in 1916 and was likely introduced in infested iris bulbs from Japan.  Since this initial introduction, Japanese beetle populations have steadily expanded westward.

Japanese beetles are problematic insects as both larvae and adults. The larvae are one of the four most common types of white grubs found in Nebraska. As a white grub, larvae feed on the roots of our grass, causing large brown dead spots in the turf that are easily lifted up like a rug from the floor. Adult Japanese beetles are 7/16 inch-long, metallic green beetles. The elytra, or wing coverings, are copper. These beetles can be distinguished from similar looking beetles by the six tufts of white hair along both sides of the abdomen. As adults, Japanese beetles feed on over 300 species of plants including trees, shrubs, fruits, vegetables, field crops, weeds, and other ornamental plant species. Some of their favorite food plants are roses, lindens, and grapes amongst others. Adult beetles feed on the foliage, flowers, and fruits of these plants. They feed on the upper surface of the leaves and cause a skeletonized pattern to the leaf where the veins of the leaf are often left behind but the rest of the leaf is chewed away. In some cases, they will consume the entire leaf. This can stress the plants, and in high populations of beetles can even kill the plant.

Green June Bug vs JB

Green June beetles are often being found this year as opposed to other years. They are very large, usually more than one-inch in length. They are dull green with some brownish coloration to the elytra and a tan border along the margins of their elytra, which are the hard wing coverings on a beetle. Green June Beetles will feed on ripe fruits and vegetables like tomatoes, corn, and grapes. They will feed on the fruits and the leaves of the plants and as an immature, they are also a white grub species.

These 2 green beetles can be controlled through multiple methods. As larvae, they are best controlled with insecticides applied to the lawn in the months of May, June, and July. There are many different options available including the most common grub control, Merit which contains imidacloprid. Pesticides can be used on the adults in plants, however, be sure to avoid use of pesticides directly on the flowers of these plants to avoid harming pollinators. Imidacloprid, sevin, eight, or other general insecticides can be used on trees and shrubs to control the beetles. In low adult populations, you can hand pick the beetles off of plants and throw them into a bucket of soapy water to kill them and not harm any pollinators.

Yard and Garden: July 7, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for July 7, 2017. 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 28, 2017. 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: Bob Henrickson, Assistant Director of the Nebraska Statewide Arboretum

If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/44qr and be entered to win a free plant book or some free UNL gifts.

1.The first caller of the day has 10 lilacs growing in a lawn which are now getting a gray film on the leaves. What is causing this problem?

A. This is due to powdery mildew. This is a common problem on lilacs. Lilacs often get this disease if they are planted too closely together reducing air flow or if they are planted in heavy shade. If these plants are not growing in either of these environments, it is likely due to the wet spring we saw this year. Fortunately, this disease is not very damaging to the plants and there is no need to treat for it.

2. A caller has many American elm trees growing in his pasture that seem to suddenly be dying this year after the leaves turn brown and curl up on the branches.

A. Unfortunately, this is likely due to Dutch Elm Disease, which is still present and active in Nebraska. Many of our trees can grow for a few years and then the trees get large enough and conditions become conducive, that it shows up and kills the trees fairly quickly. The only management strategy is to remove and destroy the infected trees to reduce the spread to other trees.

chicory, Joseph M Ditomaso, Univ of CA-Davis, bugwood

Photo of Chicory from Joseph M DiTomaso, University of California-Davis, Bugwood.org

3. What are the blue flowers blooming along the roadside now and can the seed be purchased somewhere?

A. That is chicory, a non-native plant often used in roadside mixes. The seed can be found in some roadside mixes or at local seed sources.

4. A caller has a sunset maple with leaves that are curling and falling off the tree. What could be wrong with the tree?

A. This could be due to herbicide drift. Trees stressed by herbicide drift will often lose their leaves and push new growth. As long as they are producing new leaves that are not curled, the tree will likely be fine. However, many years of damage from herbicide drift can cause more stress and even possibly death.

5. This caller has voles in their yard. How can these be controlled?

A. Snap mouse traps can be placed in the runs perpendicular to the runs. These traps will catch and kill the mice. Here is a guide on vole control

6. A caller has a copper-colored beetle in her elm trees that are causing holes in the leaves. What would this be and how can they be controlled?

A. This could be a Japanese Beetle, an invasive insect from Japan. It is a green beetle with copper-colored wings. These beetles need to be controlled as they can do a lot of damage quickly. They chew on the leaves causing a skeletonization of the leaves as they leave behind the leaf veins. They can be treated with a insecticide containing imidacloprid.

7. A caller has a grass that grows in her lawn. The grass grows in a large circle about the size of a dinner plate and tends to turn brown in any kind of drought when the rest of the lawn does fine, but thrives in higher moisture content. What would this be and how can she make her lawn look more uniform?

A. This could be a cool season weedy grass species. They are often found in our lawns growing in a large circle. I would recommend spot spraying the areas of this different type of grass and then reseeding. This would be best done this fall. Be sure to spray the spot while it is still green and actively growing and use a product such as glyphosate. Overseed the areas in September.

8. This caller has hollyhocks with brown spots on the leaves. What could this be from?

A. This is likely due to hollyhock rust, a common fungus of hollyhocks. Remove the leaves as they develop the disease and destroy the leaves and plant parts removed in the fall cleanup. Fungicides can be used if necessary, such as a liquid copper fungicide.

9. A caller has peach trees that have developed some insects in the peaches making them unedible. What can be done about that?

A. There are a lot of different insects that feed on the fruits of peaches. The oriental fruit moth is one. For any fruit tree, either deal with some insect and disease damages throughout the years or keep your trees on a spray program. Spray every 10-14 days throughout the growing season with an Orchard fruit tree spray that contains two insecticides and a fungicide. Avoid spraying during full bloom. For more information, visit food.unl.edu/local-food-production

10. This caller has a sycamore that has shed some leaves and is now shedding bark. What is wrong with the tree?

A. The shedding bark could be normal. Sycamore trees have an exfoliating bark that is normal to give it the camouflage bark appearance. It may have been hit earlier this spring with anthracnose causing the leaves to drop. Anthracnose is a minor, but common, disease of sycamore trees. It is more prevalent in wet weather, such as this spring. There is no control for it, but the tree should be fine.

11. A caller has been trying to seed grass where a septic tank was and can’t get it to grow. What is wrong?

A. At this point in the year, it would be best to wait until fall to plant grass seed due to the heat, humidity, and lack of rain. However, if you have been trying in the spring and fall and can’t get it to grow, I would recommend getting a soil test done of the soil where this problem is occurring. This will help tell if the soil has other problems because of the septic tank or what was put back into the hole. It was also determined that this is an area around a large tree with a great deal of shade, if the area is too shady for grass, try a groundcover or a carex species that will grow better in more shade.

12. When is the best time to spray for bagworms?

A. Now would be a good time since the bags have emerged. Make sure you spray before the bags are 1 inch in length for best control. You can use any general insecticide for controlling bagworms such as sevin, eight, bifenthrin, tempo, or Bt can be used for a safer control method. Bt will not harm bees and other beneficial insects.

13. A caller has a Norway Spruce that is 8 feet tall. It has been drying up since this spring and looks like it is dying. The tree has been planted here for 5-6 years and is watering slowly every 2 weeks since the trees were planted. What is causing it to die?

A. This could be due to overwatering. The roots of the trees need to breathe in between waterings. If the caller is filling a moat around the trees with water every 2 weeks for this many years, it would be excessive.

14. The final caller of the day wondered if the yard could be sprayed to help with chiggers? He also wondered when the time was to use sedgehammer on the lawn?

A. Nothing can be sprayed on the lawn to entirely help with chiggers. The best defense against chiggers would be to use insect repellent that contains DEET and to wear light colored clothing. Sedgehammer is best used before June 21st or the longest day of the year to help reduce the populations of nutsedge for next year. However, it can still be used this late in the year to kill what is in the lawn this year.

Poor Pollination

Poor Pollination, Blog post

Summer is a great time of the year. Our flowers are blooming and our gardens are growing. However, sometimes we have disappointments in the garden such as when our vegetable crops don’t produce viable fruits for us to eat. There are many reasons for that, but most of them we cannot help with. Just be patient and they will work themselves out.

Zucchini, squash, and cucumbers have been known to produce fruits that develop into only a small fruit that then falls off the plant. The reason for this is due to poor pollination. The plants in the cucurbit family have separate male and female flowers. This time of the year, only the male plants are present in the plants. To have a fully pollinated fruit that will develop to maturity, the plant needs the female flower to provide the fruit itself, but it needs to be pollinated by the male flower. A female flower is easily identified because you will see a small forming fruit behind the flower. Often times, people see the flowers on the plant and then get discouraged because a fruit doesn’t form, but both types of flowers are necessary to get fruits.

Poor pollination can also be caused due to lack of pollinators. Bees and other insects are necessary in cucurbits to ensure that the pollen is moved from the male flowers to the female flowers. Some years the weather isn’t desirable to the pollinators or we have a low number of pollinators present, which will lead to poor pollination causing the small fruits to drop off before fully developing. This year it has been quite rainy which leads to less pollination because bees don’t like to fly in the rain. Be careful when spraying for squash bugs and squash vine borers to help reduce injury to pollinating insects.

blossom end rot zucchini

Blossom End Rot on Zucchini

Blossom end rot is another reason that small fruits may not fully develop and then fall of your plants. Blossom end rot is an environmental problem that affects many of the plants in our garden including tomatoes, peppers, cucumbers, squash, zucchini, and watermelons. This is actually a calcium deficiency within our plants. Calcium is often found in adequate quantities in Nebraska soils, however, it cannot be moved throughout the soil and into the plant without even moisture. So, the problem isn’t due to lack of calcium, it is due to uneven moisture in the soils. In Nebraska, especially in the beginning stages of plant development, moisture is typically uneven due to heavy rains in between dry spells. Using calcium on your plants will not help this issue. Give the plants time and they should begin to develop normal fruits with no blossom end rot on them later in the season. Typically, we only see blossom end rot for the first couple of harvests in a season. You can still eat the fruits that develop with blossom end rot, you would just need to cut the rotten portion of the fruit off.

2015-09-22 18.45.39

Squash bugs on a Zucchini

Squash bugs and squash vine borer are coming to take over our gardens soon. This is the time of year to watch out for these problematic, common insects found affecting our cucumbers, zucchini, and the other cucurbits. Pay attention to your garden to help prevent damage. You can scout for the eggs of the squash bug. You will notice a group of tiny, copper colored eggs gathered near the intersection of the veins on the underside of the leaves. Remove and destroy the eggs as you find them to reduce the population. For squash vine borer, wrap the base of the plant in aluminum foil to stop the females from laying the eggs on your plant. You can use insecticides for both of these, just be careful to do it in the evening when the bees aren’t flying and don’t spray the flowers with insecticides to help with pollination.