Wild Cucumber

Windbreaks are very important to many acreage owners throughout Nebraska. A windbreak is used to block the wind, as the name implies. Winter winds can be very strong and a windbreak will help to reduce those winds, which will in turn reduce heating bills. Windbreaks can be built from a variety of trees and shrubs which are typically fairly tolerant of many problems. However, we do still see problems from bagworms, some fungal diseases, and weeds growing around the trees. A windbreak weed that is quite prevalent this year is wild cucumber or burcucumber.

About Wild Cucumber

Wild cucumber is an annual weed that grows up and over our windbreak trees. Due to all the rain we saw this spring, it is growing voraciously over our trees across the Nebraska countryside. It vines and has leaves similar to cucumber plants. The leaves are arranged alternately along the stem and have five triangular-shaped lobes on the leaves. The leaves are large, 4-10 cm long and 4-13 cm wide. If left on the trees long enough, a fruit will develop. The fruits of wild cucumber resemble a shorter, stouter cucumber with spines all around the outside. The plant climbs up onto our desired trees through the use of tendrils that twist around small branches to hold the plant up as it grows.

There is also a burcucumber plant which is closely related to wild cucumber. Burcucumber is also an annual weed that vines up and over windbreak trees. The leaves of burcucumber are more rounded and the lobes are not as deep as the lobes on the leaves of wild cucumber. Also, the fruits of burcucumber are much smaller and held in a groups. Wild cucumber and burcucumber are similar enough that management for both plants is the same and the names are often used interchangeably.

Managing Wild Cucumber

Wild cucumber is a plant with a shallow root system, so it pulls very easily. At this time of the year, this is really the only way to manage wild cucumber. Don’t spray 2,4-D or any other herbicide on the vines because anything that would control the wild cucumber can damage or even kill the trees that wild cucumber is vining up on. It would be best to pull it off and kill the plant before any fruits are produced to reduce the seedbed. However, at this time of the year they have already begun to produce fruits.

Since wild cucumber is an annual plant, it can be controlled with a pre-emergence herbicide in the spring. Products containing simazine will work to control this weed before it emerges next spring. Early May would be a great time to apply the chemical around the trees in your windbreak to make sure it is in the soil before the wild cucumber germinates. If you are having troubles with this weed this year due to the excess moisture, it would be beneficial to use the simazine next spring or you could have a similar or worse problem next year.

Weather & Plants

 

The environment impacts our plants in many ways. We are always happy to see the shift in weather to help the heating and air conditioning costs of our homes. Plants are also very happy when the weather changes to a more comfortable temperature. Extremes for moisture and temperature can be very damaging to our plants on both ends of the spectrum. This year we have seen a wide range of these problems which are negatively impacting our plants. To say we have a “normal” growing environment or weather pattern in Nebraska is almost unheard of and this year was unlike any we have seen recently.

Floods

2015-06-04 18.32.28Typically we are excited to see rain throughout the season. However, when the rain doesn’t seem to end, like this spring and even again now, this can harm our plants. There is such a thing as overwatering plants. Plant roots need to breathe too, if they don’t have the oxygen they need they can start to develop root or crown rot that can kill the plant.

Besides problems with root growth and development, many fungal diseases have been popping up on our trees this summer. There are many leaf spots on our trees such as maples, oaks, pears, and crabapples as well as on our vegetable crops such as tomatoes, cucumbers, and others. The cool, rainy environment this spring led to the infection which is showing up now. Spraying so late in the season won’t really help. The best thing for these plants is to just keep them healthy through the season and then use sanitation in the fall to reduce the diseases next year. Destroy fallen leaves at the end of the season by raking them up and throwing them into the garbage and remove annual plants from the garden. Don’t compost infected plant parts because the spores may not be killed in a compost pile. Leaves left at the base of the plant or vegetable plants left in the garden will make a good location for the disease spores to overwinter and move back into the plant next spring.

Heat

Hot temperatures can be problematic for our plants, especially when that heat comes on fast after such a long, cool spring and winter. We have had problems with leaf scorch showing up on plants when we had that swing of temperatures into the 100’s with high humidity. This extreme heat is damaging to our plants, but especially this year when they were accustomed to cooler temperatures with more than enough water available to them. Scorch is still apparent on trees even though temperatures have cooled back off. For the survival and health of our plants through extreme heat, keep a 2-3 inch layer of mulch around the plants and keep them well watered when rains end in the summer.

Excessive cold

Excessive cold temperatures that we saw this winter can also harm our plants. The good thing for Southeast Nebraska was that we had snow cover most of the winter this year. If we had seen that much wind and cold temperatures without snow insulating the roots and crowns of our plants, we would have seen a lot more dieback.

Some of our plants did still have problems from the cold and some had problems from the high salt buildup around our plants from all the snow. Evergreen plants still transpire through the winter months. Desiccation happens when the moisture released from plants through transpiration exceeds moisture taken in through the roots. White pines see desiccation quite often in the winter months on the north side from the strong winter winds we see in Nebraska. This desiccation becomes even worse on plants that are in an area where snow with deicing salts are piled up each time we scoop snow.

There isn’t much to be done to fix trees now that desiccation has set in. For this coming winter, it would help to water the trees once a month on a warm day in the winter. You can also apply anti-desiccant products once every six weeks beginning after plants have completely hardened off, usually in late November. Continue applications through mid to late February. Avoid covering plants so heavily they become sticky with needles glued together. Have warm, soapy water nearby and clean out the sprayer immediately or equipment may be ruined by the product.

Moisture Problems for Trees and Other Landscape Plants

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The excess rain this year is a change from many years where we are already worried about drought stress on our landscapes. However, excess moisture is causing problems in our landscapes this year from fungal diseases as well as nutrient deficiencies.

Chlorosis

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Photo of Chlorosis by Amy Cogswell

Chlorosis is a condition that occurs to many tree species with symptoms of the leaves or needles developing an abnormally light green or yellow color. Chlorosis is typically caused by a deficiency of iron in the plant tissues. With iron chlorosis, the leaves will be lime green in color while the veins of the leaves remain darker green. Chlorosis can also be caused by over-watering, over-fertilization, and damage to roots among other things. This year, with the high levels of moisture we have seen this spring and summer have led to a lot of chlorosis in trees like birches, maples and oaks.

Chlorosis happens commonly in southeast Nebraska soils because of our high pH levels. The pH in an alkaline or clay soil is higher and that high pH will tie up the iron making it unavailable to trees. Iron is sufficient in the soil but it is not available to the tree. In overwatered or compacted soils, the roots have low oxygen levels that can affect the ability of the roots to pick up iron and other micronutrients. The excessive rains this year have caused more chlorosis than other years because the roots are lacking oxygen and can’t pick up the nutrients they need. 

Anthracnose

Anthracnose is a fungal disease that affects the leaves of many ornamental trees. It is seen primarily on sycamores and maples but can be seen on many trees including oaks, ash, and walnut. It causes irregularly shaped brown areas on the leaves. The affected portions of the leaf will follow the veins and will eventually cause death of the leaf and stem tissue. This disease is primarily an aesthetic issue, it will not kill the tree, at least not in only one year of infection. Because of this, Fungicides are rarely recommended.

Anthracnose is more common under cool, wet conditions, which is why we are seeing it this year. The fungi is host specific, so if anthracnose affects your ash tree, that fungi will not spread to the maple tree. However, if the conditions are favorable for anthracnose on one host, it is likely that it will be found in multiple hosts.

There is an anthracnose found in cucumbers and other cucurbit or vine crops in the garden as welll. If your cucumbers have anthracnose on some leaves, pinch those leaves off and destroy them, don’t compost them and don’t leave them around your plants. Fungicides are not usually cost effective for home gardeners, but mancozeb or other copper fungicides can be used to minimize damage to plants if desired. Be sure to read and follow all instructions on the product label.

Septoria Leaf Spot

Septoria leaf spot is a problem showing up this year on our perennial plants including mums, coneflowers, coreopsis, blanket flower, lambs ear, and many more. This is another fungal disease showing up with all of the rain this year. With septoria, purplish to brown colored spots will develop on the leaves, sometimes completely covering the leaves. It tends to start on the older foliage of the plant, but if overhead irrigation or excessive rain events continue, it can continue to spread through the plant. If you see Septoria leaf spot in your garden, remove infected plant parts. Fungicides such as copper can be used for Septoria leaf spot as well if desired.

Septoria leaf spot can also be found in tomato plants. It will appear on the leaves as small spots with a whitish center and dark colored border. Eventually the spots can coalesce into larger spots and destroy entire leaves. It can lead to defoliation and in severe cases even death of the plants. As you see Septoria leaf spot on your tomato plants, remove the foliage. Copper fungicides can also be used but should be used at first sign of the disease to reduce the spread. Also, avoid overhead irrigation to reduce spores splashing and spreading the disease; water only at the base of the plants.

 

Annuals for Shade

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Coleus picture from Pixabay

A couple of weeks ago, I wrote about annuals for color. That article focused on annuals for color in full-sun locations, however there are a lot of great choices for shady locations of your landscape as well or if you live in an apartment with only shade on your balcony or have a patio or garden space in the shade. So, I thought I would take the time to give you a selection of good shade tolerant annuals as well.

Tuberous Begonia

Tuberous Begonia is a common shade plant found at the garden center. They can be found in basically all flower colors except blue and the flowers may be single or double. The plants can grow upright or as a trailing plant. Trailing varieties of tuberous begonia are often found in hanging baskets and are popular as a Mother’s Day gift. Tuberous begonias can also be kept over the winter to replant and enjoy new each season. Save the tubers from the plant and then repot them in February to early March and enjoy them as they grow again the next year.

Caladium

Caladium is a fun plant for the shade that will not survive our winters, so it is grown as an annual here. This is a plant that is used mostly for the leaves, not for the flowers. The leaves can be found in shades of green, white, red, and pink and they are large and tropical in appearance. They grow best in moist, shady areas of your landscape where many other plants will not thrive. They will take part shade as well. If caladiums are planted in areas with too much sunlight, the leaves will scorch and turn brown and papery. Caladiums can also be planted in containers placed in a shady location.

Coleus

Coleus is another shade plant that we grow for the foliage, not for the flowers. Coleus can be found in many shades of green with pink, purple, white, red, and orange. There are even mixes that have multiple color combinations together. Depending on the variety they can be only 1 foot tall up to 3 feet tall and wide. There are also sun varieties but be sure to plant shade varieties in the shade and sun varieties in the sun for brightest colors and most vigorous growth. These plants can be grown year-round indoors in a container, but outdoors in Nebraska, they will not survive the winter conditions.

Impatiens

Impatiens are a fun addition of color to a shady spot in your garden in shade planters. The typical impatiens are coral or a mix, but they can be found in the pinks, reds, oranges, coral, and white. These are tough and fairly easy to grow for the gardener of any age. There are now varieties of impatiens that can be grown in full sun, called the SunPatiens. They will grow in full sun, part shade, and full shade, making them very adaptable and a great addition to our landscapes and container gardens. Impatiens often get downy mildew, choose a variety that is resistant to this disease to help maintain your flowering through the season. New Guinea impatiens are another species of impatiens that can survive in more sunlight than traditional garden impatiens but require a lot of water to thrive in that location. New guinea impatiens are the impatiens with large, brightly colored bronze or purple leaves typically with a pink midrib. For a full sun option with less water requirements, choose the sunpatiens that are better suited for this location and have resistance to downy mildew.

Torenia

Torenia is a fun shade annual. I added it to my shade container gardens one year when I lived in an apartment with a North facing patio to add something different. They have a small, blue flower that reminded me of a snapdragon style of flower but it grew well in the shade. It is a little less known, but it can be found at most garden centers.

These plants are shade loving, but not necessarily full shade. They will all tolerate part to full shade. They should have 4 hours or less of sun and that sun shouldn’t be only in the afternoon. It should be more morning sun with some early afternoon or early evening sun as well. So, even if you have a location where you can only have containerized plants and you only have space for them in a shady location of your landscape, there are still great choices for the shade. Annual plants can be fun to put into containers or in the ground around your perennial choices.

Annuals for Color

Now that spring is here, we can begin to think about the plant material for our landscapes. One of my favorite activities in the spring is heading out to the garden center and choosing new flowers for my garden. I like perennial plants because I can plant them one time and they will continue to come back every year. However, I also really enjoy annual flowers. They have fun colors and bloom throughout summer.

Marigold

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Big Duck Orange Marigold, Photo from the All American Selections Website

Marigolds are an old favorite flower of many gardeners. They are very easy to grow, making them a great choice for youth or for a new gardener. Marigolds come in many color options in the orange and yellow spectrum. 3 new varieties were All American Selection winners for 2019 for the Heartland region, which includes Nebraska. Big Duck Orange and Big Duck Yellow are large, longer blooming varieties. Garuda Deep Gold is a great choice that lasts with intense flower color much longer than the competition and will last up to 10 days as a cut flower. Marigolds have a lot of different varieties for single and double flowers but mostly all in the yellow-orange color spectrum.

Sunflower

Sunflowers are always a great annual flower choice. There are so many great varieties now that it is difficult to decide which ones to plant in your garden. You may think that the Sunflower is too large, but there are some smaller plants, that only grow up to 2 feet tall. There are also some new variaties like ‘Red Wave’ or ‘Chianti’ that have deep burgundy colored flowers or ‘Fun N Sun’ that is a mix of yellows, oranges, and red colored flowers. Sunflowers are great pollinator plants and they can provide you or the birds with a snack later in the season.

Snapdragon

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Snapdragons

Snapdragons are one of my favorite annual flowers and the 2019 National Garden Bureau annual flower of the year. They come in different colors and sizes and can be added to any container garden or landscape bed. Check which size you choose before you purchase to make sure that you don’t pick an annual that grows larger than the plants behind it. Remove spent flower blossoms through the season to maintain flowering throughout the summer months.

Calibrachoa

Calibrachoa is another of my favorite annual flowers due to the long list of colors and color combinations from many varieties. Calibrachoas are also sold as ‘Superbells’ or ‘Million Bells’ and it resembles a small petunia flower. These plants have a growth habit similar to the wave petunia where it spills over the edge of a container. They are also quite drought tolerant and will do well on their own for a few days if you are out of town for a weekend. It was the 2018 annual plant of the year for the National Garden Bureau. The hardest part of growing calibrachoa is deciding which varieties to plant.

Lantana

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Lantana

Lantana is a fun annual that will grow well in hot locations. It will bloom through the summer and into fall with no deadheading necessary. The common variety is a flower cluster that is red on the outside, transitioning to yellow flowers in the center, but there are varieties with pink and yellow and straight white clusters of flowers. It is a low-maintenance plant for many garden spaces and can be utilized in a container or in a landscape bed.

Annual plants can be planted in the ground or in a container. I like to use them around perennials to provide more color, for a longer period during the growing season. For the most part, they are easy to care for, some may need to be deadheaded to remove spent blooms and allow new blooms. The plants listed in this article should all be planted in full sun. The best part of using annuals in the garden is that they are typically less expensive than perennial plants and if a disease or insect problem occurs on them, you can just pull them out and you might even have time to replant. There are always new varieties of these flowers for improved flowering or new, unique color combinations or better disease resistance. Go to your local garden center and find the perfect choices to fit in with your landscape and container gardens.

Planning Your Garden

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*Reference to commercial products or trade names is made with the understanding that no discrimination is intended of those not mentioned and no endorsement by University of Nebraska–Lincoln Extension is implied for those mentioned.

In January the seed catalogs begin to arrive in the mail. Each of these catalogs is a promise that spring will come again. In all the cold, snowy weather, I like the excitement of planning my garden for this year. When you are planning your garden, keep in mind things like sunlight, location, and water availability. Planning is important for the vegetable garden as well as for flowers, trees, and shrubs.

Planning a Vegetable Garden

It is always hard not to get overwhelmed with all the fun, new plants available to us. But when planning your garden, look at the location available first. If you are planning for a vegetable garden, you need to have at least 5 hours of sunlight per day but 8-10 hours per day is ideal for vegetables, preferably more sunlight in the afternoon. If you don’t have the correct sunlight, look for shade loving plants. The garden should be in a location that is fairly level and has good soil for best growth of the plants. Be sure to plant your garden near a water source to ensure the plants get watered sufficiently through the growing season.

Also, be sure to have the proper spacing allowed for your garden plants. We tend to plant vegetable plants too close together because they are small when we plant them. Remember to space them according to the label directions. If plants are too close together it can lead to more disease and insect problems when they grow too large and overlap one another.

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Black Walnuts Photo courtesy of Paul Wray, Iowa State University, Bugwood.org

Black Walnut Trees

Another important aspect of your garden to keep in mind, would be to keep your garden at least 50 feet away from Black Walnut trees. Black Walnut trees produce juglone, which is a type of plant produced toxin that works as a weed barrier around the tree. Juglone will hinder growth and sometimes kill many different types of plants. Tomatoes are very susceptible to juglone. There are also a lot of other trees, shrubs, and perennials that are susceptible to the juglone. If you are planting near a black walnut tree, be sure to check if your plant choices are tolerant of the juglone. If you are unsure about a nearby tree, bring a sample of the tree to your local Extension Office for identification and they can help you determine which plants will do well planted near your black walnut tree.

Mulch

Mulch is a necessity for your garden. Whether it is a vegetable garden, a perennial bed, or trees or shrubs, mulch is vital to help keep weeds down and to retain moisture around plants. Mulch can be either wood chips, straw, grass clippings, or another form of organic mulch. Inorganic mulches are not the best option due to the fact that it is very hot around the roots of plants and does not retain moisture. Make sure that your mulch layer is not too deep, keep it around 2-3 inches deep and keep it uniform around the tree, avoid mulch volcanoes.

Plant Size

Make sure you always read the growing requirements and full size of the plant before planting it in your landscape. It is most economical to plant things that fit in the space in your landscape, rather than pruning or removing it later. Often times, trying to keep a plant in a space that is too small for it will lead to death and costly removal fees. So it is best to start with a plant that will grow no larger than the space available to have a long-lasting plant for that area of your landscape.

Have fun when searching through your garden catalogs and find something fun and interesting to try. The 2019 Pantone Color of the Year is Coral, try to use that in your garden this year. Check out the All-American Selections for new varieties that have been tested in real garden settings, many of them were tested in Omaha and Lincoln with help from Nebraska Extension.

Trees turn color in fall

Fall tree color blog

Fall is a great time of the year. The trees start turning colors and everything looks so beautiful, even the green conifer trees. Evergreen trees should maintain their green color all of the time, right? This time of the year I get many calls on a natural process of evergreen trees called Natural Needle Drop.

Natural Needle Drop

Natural Needle Drop
White Pine with Natural Needle Drop

Evergreen trees turning yellow in the fall may not be a problem, in fact it may be completely natural. Evergreen trees do hold onto their needles, but eventually the older needles are shed from the tree in the fall. When this happens, those needles turn yellow before they fall from the tree. As long as the needles that turn yellow are all on the interior of the tree, there is no real concern. The older needles are the needles that are shed, which will be held on the interior of the tree, not on the ends of the branches.

Natural needle drop is very noticeable on white pine trees because they are naturally not a dense tree and they lose their needles every 2 years, making it quite common. Ponderosa pines lose their needles every 3 years, while Austrian pines lose their needles every 4 years. It is not as common to notice the needle drop on these trees due to the infrequency as well as the density of the tree. Spruce trees will also lose their needles, but much less often. Spruce trees will typically hold onto the majority of their needles for up to 10 years

Deciduous Conifers

It is important to know what you tree is supposed to do in the fall and winter months. We have a couple of trees that are classified as ‘Deciduous Conifers’ meaning that they are a conifer due to their needles and how they are arranged but are deciduous because they lose those needles annually. Two deciduous conifers are commonly found in Nebraska, the Larch and Baldcypress. These trees will lose all of their needles in the fall after first turning brown throughout the entire tree. If you don’t know what type of tree you have in your yard or are not familiar with the growth habit of these trees, you might think they died, when they are really just going through their normal lifecycle.

Fall Color for Deciduous Trees

20181023_152033Speaking of deciduous trees, this is the time of the year when our deciduous trees, those with leaves rather than needles, will change color and the leaves will fall from the tree. As the nights gets cooler and the days get shorter, the tree produces a membrane between the branches and the leaves which causes the leaves to be shed from the tree. Prior to leaf drop, this membrane also causes cessation of chlorophyll from the leaves for the year. At this time, the other pigments are allowed to show up in the leaves.

The brightest fall colors are produced when dry, sunny days are followed by cool, dry nights. The dry, sunny days are needed to break-down the chlorophyll in the leaves allowing the other pigments to be dominant in the leaves. The cool, dry nights are also necessary for fall color because trees need to avoid freezing temperatures which can injure or kill the leaves causing them to stop producing much sugar at all. The sugar content is what increases the amount of the anthocyanin, or red pigment.