Lilacs are a staple of the spring to bring us a wonderful scent and beautiful flowers. Later in the season they may not be as exciting in our landscapes, but it is still disappointing to see them have problems. We are seeing a few problems in lilacs this summer.
Pseudocercospora is a fungal disease found on lilacs and has been quite common this year. It is the damage in the photo in this article. It shows up as brown spots on the leaves, moving from the edge of the leaves inward, sometimes splotchy in appearance. This fungus becomes active in moderate temperatures and high humidity. It is common when temperatures are around 76 degrees but the infection occurs at least 7 days before any symptoms are seen on the plant. The moderate temperatures we have had this year helped this disease develop. Thanks to Kyle Broderick at the UNL Plant Diagnostic Lab for identifying this disease.
Because high humidity can cause this disease to develop, increasing the airflow around the lilacs can help reduce the disease. The fungus can survive for at least 2 years on plant debris, so fall cleanup of the infected leaves can also help to reduce the disease. Fungicides are not effective at this time of the year and may not always be effective. If using a fungicide, it should be applied in the spring when the leaves first emerge. The best option for management, would be to cut out 1/3 of the plant, removing the largest canes and those canes that are cankered or girdled and those that are completely dead. A rejuvenation cutting could be done if you can’t prune by just removing some canes. The plant will not rebloom for a couple of years after rejuvenation if you do this process.
Powdery mildew is a fungus common on lilacs as well. It appears as a powdery substance that covers the leaves of the plant. This disease is favored by high overnight humidity and low humidity during the day with temperatures between 70-80 degrees. Powdery mildew can reduce the growth of the lilac, but rarely kills the plant.
Most often, powdery mildew shows up on the plants later in the season. If it occurs on your lilac in late summer or in the fall, there is no need to use a fungicide to control it. If the powdery mildew occurs on your plant in the spring or early summer, you may want to use a fungicide to control it. Applications with a copper fungicide should be made as soon as the disease starts to show up on the plant. However, sometimes powdery mildew shows up on lilacs that are planted in the wrong location and that lilac will see the disease every year. In this case, it might be time to transplant or just purchase a new plant for a better location in your landscape. The newer varieties of lilacs have resistance to this disease. Pruning the lilac can help with airflow and reduce this disease as well.
As a general rule of thumb, if it is a spring blooming shrub, prune it within a few weeks after it blooms in the spring. If the shrub blooms in the summer, prune it in the late winter. Lilacs should be pruned within a few weeks after blooming, so you don’t disrupt the bloom cycle. At this time of the year, the flower blossoms are already set on the plant, pruning now can reduce the amount of flowering that occurs next spring. However, when dealing with disease management, it is better to remove the diseased canes in the fall to reduce the overwintering spores for next year.
Shrubs can be pruned by heading back, thinning, shearing, or rejuvenation. Lilacs are best pruned by heading back or rejuvenation. Heading back is selectively cutting back tall or long branches to redevelop the shape of the shrub. Rejuvenation is when the shrub is cut back to 6-8 inches above ground to basically start over. Rejuvenation cutting can be useful on overgrown shrubs or those with disease or insect issues.
This year the weather has been quite abnormal. We started out with a very cool spring, after that the weather quickly shifted to hot, windy, and stormy. We are seeing quite a bit of problems with tomatoes lately and they all look similar but could be due to a few different problems.
Many people are seeing tomato plants with curling leaves. Most often these curled leaves are at the top of their plants and it is not usually all the plants that a person planted in their garden that are having problems. Sometimes it is just a couple of plants out of 10-12.
The stress from the environment can be very harmful to our plants. When the weather quickly shifted to summer this year, it caused wilting from heat and drought stress. Sometimes that environmental stress can cause the leaves of tomato plants to curl upward. Watering can sometimes help this issue, but not always. The plants may need to get over the impacts on their own. With environmental issues, the plant will eventually grow out of the damage.
Another issue caused by the environment is called physiological leaf curl that can develop on tomato plants. This is a physiological issue, meaning it is a growth response in the plant. This response is caused by changes in the environment, usually when weather shifts from spring to summer. Typically, the plant will recover on its own. Correct irrigation can help speed up this process.
Herbicide injury is something that we often see in our plants. Tomatoes are especially sensitive to drift from 2,4-D and Dicamba products. With herbicide drift, curling, cupping, and vein distortion of leaves. The plant will likely grow new leaves that are not affected and look fine. However, it is not advised to eat fruits or vegetables from plants that were hit by herbicide drift, due to the variables regarding the herbicide, there is no way to know when or if they will be safe for consumption.
This year, since we were having such a chilly spring, we were able to spray herbicides later in the season. Then, when the temperatures shifted so quickly and these products were still being used, we had a lot more volatilization of the products making them move to our plants.
There is also a virus known as Beet Curly Top that can also be found in tomatoes. The experts are suggesting that this could be part of the problem as well. The symptoms from this virus are very similar to herbicide injury. As with all virus diseases, there is no cure for the plant. It is best to pull the infected plants as soon as the virus is noticed and destroy them to reduce the chance for spread of the virus.
So, whether your plants are facing herbicide injury or a virus, the best option is to remove the plants. This will reduce the chances of all your plants getting the disease and be safest for your household. If it is an environmental issue, the plants will grow out of it. If you are unsure of the cause, it is best to remove the plants. Be sure to keep them watered as necessary through the summer to help reduce the problems.
Growing my own produce in my backyard is one of my favorite things of summer! Vegetable gardens are great exercise, give you an excuse to eat healthier, and are very enjoyable but they can be a lot of work as well. There are always problems in our vegetable gardens, usually they are temporary or easily fixed.
The weather this year has not been favorable to our plants. We have been facing low production due to heat that followed the cool, wet spring. Even though our plants are producing, the tomatoes were not ripening up. The hot weather contributes to this as well. When temperatures are consistently as hot as they were in mid-July, tomatoes may develop but they don’t turn red. According to Purdue University, the pigments responsible for the red color in our tomatoes are not produced when temperatures exceed 85 degrees. So, when we see long stretches of very hot weather, our tomatoes will not ripen. They should be turning color and becoming mature now. If they aren’t maturing and becoming ready for harvest, there may be another issue in your garden.
Blossom end rot is also starting to show up in our gardens. Blossom end rot is when the blossom end (the end not attached to the plant) begins to rot. This is due to uneven watering, which is seen quite often in the early part of the growing season where we see stretches of drought surrounded by 2-3 inch rains. Again, this should fade through the season as the plants grow through it. However, this year the constant rainy weather may cause blossom end rot to last longer. You can still eat the other end of the tomato and discard the rotted end or give your plants time, the next harvest should be better.
Cracks are also starting to appear in our tomatoes due to the wet weather. Uneven watering can cause other problems in our gardens. The heat wave followed by a 3 inch rain like what we saw a few weeks ago, can cause cracks to form in the developing fruits on tomatoes. Our fruits can grow rapidly due to rapid intake of water which can build up pressure in developing tomatoes. Cracks typically appear on the top of the tomato, often in rings, and are not harmful to us if we eat them. Check for insects that may have gotten into the cracks of our fruits before eating. The open cracks often attract insects to the fruits.
Mulch is a great way to combat these issues. Many of our problems in our gardens stem from uneven watering or plants that got too hot and dry to deal with the stresses of the environment. Mulch can keep moisture around the plants and keep the roots cooler to help with these issues as well as reduce competition from weeds. Grass clippings make a great mulch. If the grass has been treated with any herbicides this season, look at the label to know if it can be used as a mulch. If you are unsure about the herbicides applied to your lawn avoid using the clippings from your grass if it was treated with a herbicide this year. Grass clippings break down quickly so they should be reapplied often. Straw is also a great mulch for the garden and it wouldn’t need to be reapplied as often. These types of mulch can then be tilled into your garden at the end of the season or before next season to add nutrients back into your soil.
This year the weather has been abnormal, even for Nebraska. We had snow in mid-October and the cold still hasn’t fully released its grasp on us. This causes us to rethink ‘normal’ weather but it also causes problems for our plants.
Plants are slow to start
Plants are in line with the weather for this year, not necessarily with the calendar. The cool spring has slowed down or even delayed spring leafing out of many of our plants. Some plants may not even be emerging yet, which is unusual for late May. Don’t give up on these plants too soon this spring. Give the plants until early to mid-June before replacing them.
The colder temperatures this winter led to a lot damage to evergreen plants. You might be seeing browning in yews, boxwoods, and arborvitae. This damage is likely from cold temperatures and winter desiccation which occurs when transpiration from these trees exceeds infiltration of water through the roots. Wait until early June to do much pruning of these shrubs. Give the plants time to come out of the winter weather to ensure that all of the dieback is complete before pruning out the brown areas.
White pines have also turned color this year, showing quite a bit of orange-brown discoloration. This is a combination of cold weather and salt damage. Even if the trees are further away from a road, splashing from vehicles can make the salt accumulate farther away from the road than expected. White pines are also quite vulnerable to north winter winds which would cause also cause discoloration. I would not prune the white pines, they should come out of it, but it may be a while longer. Next year, to prevent so much winter desiccation, you can use an anti-desiccant in the winter months.
Seed Production in Maples
You may have also noticed problems in your maple trees recently. The calls I have received were people asking why their maple was turning brown and if it was dying. Usually the browning has been found in a particular location of the tree, often at the top. The rest of the tree is fine and leafing out correctly. The brown in the tree is actually the seeds of the maple tree. This year, the maples have produced a great number of seeds or samaras, often referred to as helicopters due to the way they float to the ground when they fall from the tree. The brown in the tree is due to the fact that these samaras are maturing and will soon fall to the ground, many have already begun to fall and litter the lawn.
The reason for this heavy seed production is the weather. This isn’t just from this year, though, it could stem back to last spring when there was a late frost that killed many of the flowers on maple trees. These trees developed more seeds this year because they were not able to produce seeds last year, according to Scott Evans from Douglas-Sarpy Extension. The cooler spring this year may have increased the high seed production this year as well. High stress events can lead to more seed production, the tree takes the stress as a signal to produce more seed just in case the stress is deadly.
Seed Production in Conifers
Many people have also asked about brown structures at the ends of the branches on their conifers. These structures are just the pollinating cones. The concern is whether they are bag worms because they resemble a small bagworm structure. Typically these structures would appear earlier in the spring and may not even be noticed. But with the cooler spring, the production of these small cones is coinciding with the time that we can start to see bagworms. This is a normal process for evergreen trees and nothing is wrong with them when these cones appear. Bagworms will likely be later this year than normal years due to the temperatures.
Spring will be here before we know it, which is very exciting for plant enthusiasts. We can get outside and do some cleanup once it starts to get warm. Don’t get too excited though, winter could still show up for a couple more months. One thing you can do now, though, is plan your garden.
Choose Well-Adapted Plants
When planning your garden, pay close attention to the growing requirements of the plants you choose. Select plants that are suited for your growing zone. Southeast Nebraska is in zone 5B. Also, utilize plants that have similar growing conditions for each area or garden in your landscape. For example, shade plants should be planted with other shade plants and water loving plants should not be planted with drought tolerant plants.
Be Water Wise
Nebraska often sees periods of drought through the hot part of the summer. For water saving options, look to drought tolerant plants. Some good choices for drought tolerant plants include
Yarrow, Achillea spp.
Russian sage, Perovskia atriplicifolia
Coneflower, Echinacea spp.
Black-eyed Susan, Rudbeckia hirta
Daylily, Hemerocallis spp.
Salvia, Salvia spp.
Viburnums, Viburnum spp.
Ninebark, Physocarpus opulifolius
Maidengrass, Miscanthus sinense
Big Bluestem, Andropogon gerardii
Little Bluestem, Schizachrium scoparium
These plants will grow well with no supplemental water in normal precipitation. There are also quite a few plants that need very low amounts of supplemental water, which are good choices as well, these include
Shrub Roses, Rosa spp.
Penstemon/Beardtongue, Penstemon spp.
Plumbago/Leadwort, Ceratostigma plumbaginoides
Coral Bells, Heuchera spp.
Butterfly Milkweed, Asclepias tuberosa
Lilies, Lilium spp.
Phlox, Phlox paniculata
Why does it matter if you use drought tolerant plants? These plants will survive better in our summer environment when it gets very hot and dry. Also, this will help reduce the amount of water we are applying to our landscapes. Water is limited in supply and costly to use. If we minimize the amount of water needed for irrigation, everyone will benefit.
When to Water
Remember, if you are utilizing plants that are more drought tolerant, only water when necessary. Plants will tell you when they need to be watered, they will begin to wilt and show signs of water stress before reaching the permanent wilting point from which they will not recover. Many times, too much water is used in low water-use landscapes due to the tendency of homeowners to overwater.
Take Control of Your Irrigation System
There is also a tendency to overwater with in-ground or automatic sprinkler systems. Many times people use the “set it and forget it” thought process for watering the lawn with an automatic system, but that will actually use more water than what is needed. According to the American Water Works Association Research Foundation, the research from 2000 shows that homes with in-ground sprinkler systems use 35% more water than those without an in-ground sprinkler system. Those who have automatic timers to control those in-ground sprinkler systems use 47% more water than those without timers. It is better to only turn on the sprinkler system when you need to water rather than having it run all season on certain days or times. Also, make sure that you turn the sprinklers off in the rain or just following a rain event, or purchase a water sensor for your landscape to avoid watering when the soil is wet.
Economic Benefits of Landscaping
These statements are not meant to deter people from having a nice landscape. In fact, landscapes can increase the value in your home, reduce crimes, increase the rate of healing at a hospital, provide oxygen, and decrease carbon dioxide in the environment. According to research done by Colorado State University, there are 25% fewer crimes in public housing with landscapes, children who spend time outdoors are better learners, and every $1 invested in a home landscape yields a $1.35 return on the investment.
This is the Q&A for the Yard and Garden show for May 26, 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: Laurie Stepanek, Forest Health Specialist 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 a bleeding heart plant that she wants to plant but the area she wants to plant it in is full sun all day. Will it be ok in that environment?
A. No, this is a shade plant. When plants that need part to full shade, such as bleeding hearts, are planted in full sun, the leaves will begin to burn as the summer goes on and it will not survive as long or produce as many flowers. The east side or the north side of a building is best for these plants where they may have morning sun but are protected from the afternoon sun.
2. A caller has some boxwoods that looked good in February but now have areas of dying leaves. What is this from and can it be fixed?
A. This is from winter desiccation. This winter was very dry and caused a great deal of damage to a lot of different evergreens and broadleaf evergreens. During the winter our evergreens are still transpiring. When we don’t get additional moisture naturally and the transpiration exceeds the moisture absorbed by the roots, the plants will show winter burn or winter kill. This can be pruned out and many plants will be just fine. However, if the damage takes the pruning into the part of the plant where leaves are absent, then it may be time to replace this particular shrub. Boxwoods are often damaged in Nebraska, so a Yew may be a better replacement.
3. This caller has a mailbox in full sun just off the street that is very hot for plants. Is there a type of groundcover that will survive and do better in this location than a rose moss has done in the past?
A. Sedum, Rose Moss, Dianthus, Rock rose, Cacti, Ice Plant, Basket of Gold, Wall Rock-cress, Hens and chicks, or Catmint could all be used in this area and will thrive. It may take a few of these plants to fill in, but they will be great after time.
4. A caller wanted to know what to do for transplanting and preparing a site for grapes?
A. Here is a good guide from Oregon State University on growing grapes. You can also find a lot of great information on grapes and other fruits from Connie Fisk on the Food.unl.edu website
5. A caller wants to know why his fruit bushes are not growing well? He is growing boysenberry, raspberry, and others that are planted in part shade on the East side of a building.
A. All of our small fruits would need to be planted in full sun. Try moving them to a location with at least 6-8 hours of sunlight per day, afternoon sun is best.
6. This caller has oak trees that have signs of 2,4-D drift. What can he do to help them? Will they survive?
A. These plants may drop their leaves and push new growth to help overcome the damage from the herbicide drift. There is not much you can do to help them through other than to keep the trees otherwise healthy. Ensure they are getting correct waterings and keep a mulch ring that is 2-3 inches deep. This damage may have also been from Dicamba, which is an active ingredient in Trimec and is causing many problems in our oak trees as well as many other tree species. Make sure when you apply pesticides you are reading and following the label, spray with low wind and cooler temperatures. Dicamba can turn into a gas and move to non-target plants in temperatures above 80 degrees. It can volatilize for up to 72 hours after application.
7. The cherries on a tree bloomed and were developing, now the cherries are brown and dead. What caused it? Can anything be done to fix the problem?
A. This could be due to a frost issue or due to brown rot. There is no way to fix it now that it has happened. If it is brown rot, you might try an Orchard Fruit Tree spray next spring to reduce the disease.
8. A caller has swamp white oak trees that leaves are curly on the old growth, but the new growth looks normal. What would cause this?
A. This is from a herbicide drift issue. The first flush of growth was affected by the herbicide damage but the new growth would be free from damage. Our trees will push secondary growth after being hit by pesticides and the new growth will be fine. There is nothing to do for it and the tree should be fine.
9. Do containers need new soil every year?
A. It is best to replace at least the top 4-6 inches of soil with new soil in containers each year to ensure there are enough nutrients to help the plants through the season. After one growing season, in a container, the plant will use up the majority of the nutrients in the soil.
10. A caller has a Japanese Maple that was growing in part shade, but many of the trees shading it were removed and now it is mostly in full sun. The bark on the south side is peeling and the branches on the south side are dying. Can it be saved?
A. This is a great deal of environmental stress to the tree that now cannot be changed. The tree has little chance of survival at this point.
11. Can herbicide drift come from granule products as well?
A. The granule drift comes from the wind blowing the actual granules, or the soil that is attached to the granules, to non-target plants and locations.
12. This caller has tomato plants growing in containers and the leaves, mostly the lower leaves, are turning brown. What can be done for this problem?
A. This is mostly due to the weather conditions we have had the past couple of weeks. Excessive rains and cloudy days have caused a slight fungus to affect the lower leaves. Pinch the damaged leaves off and ensure you water below the plant and it should recover with better environmental conditions.
13. A caller has the galls for Cedar-apple rust on his cedar trees and he also has apple and pear trees. What should he do to control this disease?
A. These are the galls that have the spores for the disease in them. In the spring, when we get rain, the galls open up and the spores are released to other trees nearby. This is a harmless problem on the cedar trees, but not to the apple and pear trees. If you have susceptible apple and pear trees where you have seen red to brown spots on the leaves in past years, you need to spray now with a fungicide spray.
This caller also has a silver maple tree with large holes that squirrels are living in. Can you control the squirrels so they don’t live in the tree?
A. There is no good way to control squirrels in the tree. Even if you trap for a couple, there are always more. The bigger concern in this situation is the decay happening in the tree. When large holes open in the tree, like this, there is decay happening in the tree. It would be best to have an arborist come in and inspect the tree to ensure it is safe.
14. This caller had 3 questions: Why are his vegetable plants already producing flowers and fruits when they are still very small? He planted peppers early and wants to fertilize them, what should he use for fertilizer? He is starting a bee-friendly prairie area that is being overrun by brome grass. What can he do to control the brome grass?
A. Many of our vegetable plants are stressed from recent rainy and cold environmental factors and are pushing flowers and even fruit on small plants. Snip or pinch off those flowers and fruits to allow the plants to push growth into the plant rather than into the production of fruits. Fertilizer can be applied as a side-dress to pepper plants now, but don’t fertilize with too heavy of Nitrogen and discontinue fertilization after this treatment. Too much nitrogen at the time when the plants should be producing fruits will cause them to produce more green, leafy material and not fruit production. Any general vegetable garden fertilizer will work. Brome grass can be controlled among broadleaf plants with grass-b-gon products to kill the grass but not the desired broadleaf plants.
15. A caller has 3 Austrian Pine trees that were spaded in 3 years ago. One isn’t growing as fast as the others and looks stunted in comparison. Should he replace the one smaller one by having a larger tree spaded in to improve uniformity?
A. The smaller tree may still pull through. However, if you have a new tree spaded in, you will have the same problem because spading a larger tree causes a lot of stress to the tree and it will take a few years for the tree to get through that stress period. So you will have the same problem with a new tree. If the smaller tree has good growth, leave it, it should get back into pace with the others.
16. This caller had some cedar trees removed a few years ago and is still having troubles getting new plants established in that area. How long will it be before he can get new plants to grow there?
A. There is no good estimate of this. The new plants are battling roots and compacted soils from years of the cedars being there. Add compost to the soil and mulch it for a year or two to help improve the soil.
17. The last caller of the day has a pin oak with yellow leaves. Why is this?
A. This is due to Iron Chlorosis, which is a deficiency of the nutrient Iron for the tree. This is very common in pin oaks in our area due to the high pH in our soils which holds on to the iron making it less available and harder for our plants to get. You can do trunk injections of iron, but that is only effective for 3-5 years each time. Iron granules are not very effective and we don’t recommend putting nails into the trunk of a tree due to the damage it causes. This is a young tree that will battle this problem its whole life. It might be time for removal and replacement with a different oak that doesn’t have so much trouble obtaining iron, such as red oaks.
With winter in full swing, it is a common practice to use deicers on our sidewalks and driveways to prevent falling on ice. With deicing agents, we need to be careful to not harm our plants when we use them and make good choices on what we use.
Deicers can cause damage to our concrete sidewalks and to our plants growing beside them. Many deicing agents contain salt substances, such as sodium chloride and potassium chloride. Because of the salt content found in these products, it can cause severe damage to our plants if too much is piled on them too often. Typical plant symptoms of salt damage include:
Desiccation (drying out)
Leaf margin and tip damage that looks as though the leaves were burned by a chemical
To avoid damage to the concrete, remove the salt as soon as you can. Deicers are meant to make shoveling easier, not to completely melt away the snow and ice. As soon as the salt melts through the ice and snow enough that it can be removed, go out and shovel it off of the concrete. When removing the snow, do it in a manner that protects the landscape plants growing in the yard. Do not pile the snow onto trees, shrubs, or flower gardens. If it has to be piled onto your landscape, move the salt onto the grass and try to do it in a manner that makes it more uniform on the grass surface. If too much salt continually gets piled up on the grass in one location, the turf can be harmed.
If you are very concerned with the effect the deicers have on your plants, you can use alternate products for melting the ice. Calcium magnesium acetate is a deicer that contains no salt. This is a safe alternative to the regular salts because it does not harm plants or animals and can be used on concrete because it doesn’t cause the damage that salt does. It is also less damaging to the environment that some of the other choices, but runoff of this product can degrade water quality in the surface water. You can also choose to use sand on your concrete, which will cause no damage to the plants in your landscape, this will not melt your ice, but it will give you traction to walk on the sidewalk. Sand and gravel will not cause any harm to your plants and minimal damage to the environment but it will have to be swept away after the snow and ice melts.
Another snow related topic is that of the snow and ice resting on your tree branches and on top of your shrubs. The snow can be removed with a broom if you desire to do so, but can be left alone to melt for no damage to the plants it is sitting on. As for the ice, let it melt naturally. Do not try to hit the ice off of the tree branches because this can cause you to break some of the branches, which will be more detrimental to the plant. If there is snow on your tree causing it to bend down, it will reform in the spring once the snow melts off of it.
A great resource that helps to identify wildflowers.
Wildflower Week is in full bloom. What exactly is Wildflower Week and what is a wildflower? Wildflowers and native plants are very versatile plants that have multiple benefits in the landscape. Some wildflowers are a cut above the rest and are worth a try in your garden.
Wildflowers are an important part of any region’s identity. Nebraska Wildflower Week celebrates this “sense of place” through wildflower-related events and activities the first week in June, when many of Nebraska’s prairies and gardens
Nebraska Statewide Arboretum (NSA) serves as coordinator for Wildflower Week activities, bringing together organizations and individuals across the state that recognizes the value of wildflowers—not only for their beauty but also for what they imply and symbolize. “Where wildflowers are thriving, is a sign that the environment is healthy,” said Bob Henrickson, whose nursery production work with the Arboretum concentrates on…
An invasive insect pest continues to move closer and closer to Nebraska, Emerald Ash Borer. Emerald Ash Borer, EAB, has not been found in Nebraska. The closest locations to Nebraska would be the Kansas City area, which is 60 miles from the southeast corner of Nebraska, and the Creston Iowa area, which is 80 miles from the Bellevue area of Nebraska.
Emerald Ash Borer is a wood boring insect that is ½ inch long and is a metallic green color with bronze underneath the wings. The problem with Emerald Ash Borer is that it bores into healthy ash trees. We have many native borer species, but they feed on stressed or dying trees, that is what makes EAB so much worse than normal borers and it is why it is destroying so many trees.
EAB is an insect that was first found in the United States in 2002, when it was found killing ash trees in southeast Michigan. Currently, Emerald Ash Borer has been found in 25 states including Iowa, Missouri, Kansas, and Colorado, but it has not been found in Nebraska.
Emerald Ash Borer feeds only on true ash trees, which means that mountain ash is not attacked because it is in a different family and is not a true ash tree. Ash trees have opposite, compound leaves with 5-11 leaflets. They have paddle-shaped seeds that stay on the tree through the fall and into the winter months. EAB has also recently been found on Fringe Tree, which is a tree in the same family as ash, but is not very common in Nebraska.
The signs of EAB infestation include suckering at the base of an ash tree, decline in the tree from the top of the canopy downward through the tree, 1/8 inch D-shaped exit holes along the trunk and branches, increased woodpecker damage, S-shaped Serpentine galleries underneath the bark of the tree. If you notice any of these symptoms in your ash tree, you should contact your local Nebraska Extension Educator.
Emerald Ash Borer treatments are not recommended until the insect is found within 15 miles of the tree’s location. There are chemical treatments that are effective against EAB. Homeowners can use a soil application, but this is most effective on trees less than 15 inches in trunk diameter. If the tree is larger, professional tree care companies can use a trunk injection. Wait until the insect is found within 15 miles before any treatment is done because the injections wound the tree and we want to wait as long as we can before we begin wounding our trees. A homeowner should also decide if the tree is in good health and a good location before beginning treatments. Planting ash trees at this time is not recommended.
At this time, the only thing we can do to help with the ever-expanding problem is to not move firewood or wood products. Buy wood locally when camping and leave unburned firewood at the campsite when you leave.
The early part of the year tends to be less eventful than much of the rest of the year. The weather is too cold to go outside and do much gardening and we tend to have to stay inside and find other ways to occupy our time. However, this is a great time of the year to get some education, such as attending the Extension Master Gardener Program.
The Nebraska Extension Master Gardener program is a horticulture related volunteer training program based in many counties throughout the state. It has been part of University of Nebraska- Lincoln Extension since 1976. Master Gardener volunteers are trained by UNL Extension faculty and staff. They contribute time as volunteers working with their local Extension office to provide horticulture-related information to their community. Participants are required to complete 40 hours of training and 40 hours of volunteer service throughout the first two years of their involvement in the program. Master Gardener volunteers retain their certification through 10 hours of annual training and 20 hours of volunteering each year.
Each year the Master Gardener program is held throughout the state, including in Gage County. The programs are held from 6:30-9:00pm on Tuesday nights at the Gage County Extension Office. This year the programs run from January 27-March 17. The schedule for the classes is as follows:
January 27, Orientation with Nicole Stoner
February 3, Waterwise Landscapes and Residential Rain Gardens with Kelly Feehan from Platte County Extension
February 10, Pruning Deciduous and Evergreen Trees and Shrubs with Kim Todd from UNL
February 17, Insects: Beneficials in the Garden and Landscape and Vegetable Insect Pests with Natalia Bjorklund from Dodge County Extension and Nicole Stoner
February 24, Wildlife Damage Management with Dennis Ferraro from UNL
March 3, Technology in the Garden and Landscape Photography for Beauty and Diagnostics with Terri James and Jim Kalisch from UNL
March 10, Preparing for Emerald Ash Borer: Identification, Management, and Treatment Options and Tree Planting Selections Now and Post EAB with Laurie Stepanek and Amy Seiler from the Nebraska Forest Service
March 17, Topic to be determined by the class with Nicole Stoner
This class will additionally be provided in Wilber following the same schedule on Wednesday afternoons from 1-3:30pm. It will run from February 4-March 25 at the Saline County Extension Office.
The cost of the Master Gardener program is $160 for the first year, which includes a book, t-shirt, and nametag. For returning Master Gardeners the cost is just $10.