K-State Research and Extension Horticulture Newsletter
  • Newsletters
  • About
  • Contact

Horticulture Newsletter 2015, No. 21

5/26/2015

0 Comments

 

Video of the Week:
How Often to Water Lawns

Turfgrass:
Too Wet to Mow the Lawn

wet grass
What do you do when the lawn can't be cut because of constant rain? The best thing to do is to set your mower as high as possible and bring it down in steps. It is always best never to take more than one third of the grass blade off at one time. If more is taken, the plant reacts by using stored energy reserves to quickly send up new growth. This reduces the amount of energy available for the plant to deal with stress or damage done by insects or disease. However, sometimes it is just not possible to keep the "one-third rule." In such cases, cut as high as possible even though it may mean you are cutting off more than one third of the blade. Bring the height down gradually by cutting more often and at progressively lower heights until you reach the target height. (Ward Upham)

Thatch Control in Warm-Season Lawns

warm season grass thatch
Thatch control for cool-season lawn grasses such as bluegrass and tall fescue is usually done in the fall but now is the time we should perform this operation for warm-season turfgrasses such as bermuda-grass and zoysiagrass. Because these operations thin the lawn, they should be performed when the lawn is in the best position to recover.
For warm-season grasses that time is June through July. Buffalograss, our other common warm-season
grass, normally does not need to be dethatched.

When thatch is less than one-half inch thick, there is little cause for concern; on the contrary, it may provide some protection to the crown (growing point) of the turfgrass. However, when thatch exceeds one-half inch in thickness, the lawn may start to deteriorate. Thatch is best kept in check by power-raking and/or core-aerating. If thatch is more than 3/4 inch thick, the lawn should be power-raked. Set the blades just deep enough to pull out the thatch. The lawn can be severely damaged by power-raking too deeply. In some cases, it may be easier to use a sod cutter
to remove the existing sod and start over with seed, sprigs or plugs.

If thatch is between one-half and a 3/4- inch, thick, core-aeration is a better choice. The soil-moisture level is important to do a good job of core-aerating. It should be neither too wet nor too dry, and the soil should crumble fairly easily when worked between your fingers. Go over the lawn enough times so that the aeration holes are about 2 inches apart. Excessive thatch accumulation can be prevented by not over-fertilizing with nitrogen. Frequent,
light watering also encourages thatch. Water only when needed, and attempt to wet the entire root zone of the turf with each irrigation.

Finally, where thatch is excessive, control should be viewed as a long-term, integrated process (i.e., to include proper mowing, watering, and fertilizing) rather than a one-shot cure. One power-raking or core-aeration will seldom solve the problem. (Ward Upham)

Time to Fertilize Warm-Season Grass

lawn of warm season grass
June is the time to fertilize warm-season lawn grasses such as bermudagrass, buffalograss, and zoysiagrass. These species all thrive in warmer summer weather, so this is the time they respond best to fertilization. The most important nutrient is nitrogen (N), and these three species need it in varying amounts.

Bermudagrass requires the most nitrogen. High-quality bermuda stands need about 4 lbs. N per 1,000 sq. ft. during the season (low maintenance areas can get by on 2 lbs.). Apply this as four separate applications, about 4 weeks
apart, of 1 lb. N per 1,000 sq. ft. starting in early May. It is already too late for the May application, but the June application is just around the corner. The nitrogen can come from either a quick- or slow-release source. Plan the last application for no later than August 15. This helps ensure the bermudagrass is not overstimulated, making it susceptible to winter-kill.

Zoysiagrass grows more slowly than bermudagrass and is prone to develop thatch. Consequently, it does not need as much nitrogen. In fact, too much is worse than too little. One and one-half to 2 pounds N per 1,000 sq. ft. during the season is sufficient. Split the total in two and apply once in early June and again around mid-July. Slow-release N is preferable but quick-release is acceptable.

Buffalograss requires the least nitrogen of all lawn species commonly grown in Kansas. It will survive and persist with no supplemental nitrogen, but giving it 1 lb. N per 1,000 sq. ft. will improve color and density. This application should be made in early June. For a little darker color, fertilize it as described for zoysiagrass in the previous paragraph, but do not apply more than a total of 2 lb. N per 1,000 sq. ft. in one season. Buffalograss tends to get weedy when given too much nitrogen. As with zoysia, slow-release N is preferable, but fast-release is also OK. As
for all turfgrasses, phosphorus and potassium are best applied according to soil test results because many soils already have adequate amounts of these nutrients for turfgrass growth. If you need to apply phosphorus or potassium, it is best to core aerate beforehand to insure the nutrients reach the roots. (Ward Upham)

Ornamentals:
Trees Not Leafing Out

Tree not leafing out
We have had numerous reports of trees not leafing out or putting out only a fraction of the leaves normally borne. We believe much of this is due to the quick drop in temperature from November 10 to 11 last year. We went from a high of 69 degrees on November 10 to a low of 19 the following morning. Many trees had not hardened off and were damaged.

If a tree hasn’t leafed out at all, check the stems. If they are dry and brittle, that part of the tree is dead. However, sometimes the tips of the branches are dead but the tree is alive further back. Take a knife and shave off the outer bark on several small-diameter, young branches. If the tissue underneath is water soaked or dark brown to black in color, then it is likely dead. This cambium layer should be a greenish-white color. As long as the twigs remain supple and the tissue under the bark isn’t dark, there is hope.

So, what should we do for these trees? Help them avoid stress. This means watering during dry weather so the tree has good sap flow. Trees transplanted within the last couple of years should be watered every week during dry weather. More established trees should be watered every two weeks if there is no rainfall.

On young trees, kill all the grass under the tree and mulch. Reducing root competition makes for a healthier tree that is more likely to recover.

And finally, remove any dead wood so that insects and disease do not have a point of entry. Dead wood can be removed any time of year. (Ward Upham)

Miscellaneous:
Sidedressing Chart Available

annual flower
Gregg Eyestone, Horticulture Agent from Riley County, has put together a nice chart that covers sidedressing nitrogen on annual flowers, certain perennial flowers, vegetables and various small fruit. Sidedressing (also called topdressing) is applying nitrogen fertilizer as plants are growing to give them an extra boost. Done correctly, sidedressing can improve vegetable, fruit and flower production. Gregg lists the crop, the amount of fertilizer needed, and suggested time of application. Rates are given for ammonium sulfate, urea and blood meal. You may find the chart at http://www.hfrr.ksu.edu/doc3952.ashx (Ward Upham)

Excessive Rain Can Cause Leaf Problems

tree leaves turning color
Leaves Turning Yellow or Red: In Kansas we often see chlorosis (yellowing) of plant leaves due to high pH soils making iron unavailable. However, there can other causes that result in similar symptoms. For example, we have received so much rain in certain parts of the state recently that plants are unable to take up the nutrients needed to maintain a good green color. The cause of this condition is actually a lack of oxygen in the soil due to soil pore space being filled with water. This lack of oxygen to the roots often results in a yellowing of foliage. In certain plants such as oaks and maples, however, it may also lead to a reddening of some of the newer leaves. Fortunately, color changes due to wet soils will be corrected as soils dry. Plants should regain their color when we return to more normal weather.

Trees Shedding Leaves: If trees shed leaves in a general shedding with all parts of the tree losing some leaves, then there is no cause for concern. A general shedding of the leaves is most often due to weather turning hot and dry. The tree drops leaves because the root system can no longer keep up. Dropping leaves helps balance the amount of water available from the root system and the amount needed by the leaves.

However, the same thing can happen if the soil is too wet. A lack of oxygen in the soil compromises the root system so it can no longer support all the leaves. Therefore, the tree drops some leaves to bring the tree roots and leaves back into balance. The tree will retain more than enough leaves to remain healthy. (Ward Upham)

Pests:
Bristly Rose Slug

Bristly Rose Slub
This insect has been skeletonizing rose leaves in the Kansas City area. This is not a caterpillar but is the larva of a sawfly. Close examination of this small (½ inch) larva will reveal very fine, hairlike spines in clusters.

Young larvae will remove the green layer of a leaf leaving behind a clear material. As the larvae mature, they make holes in the leaf and eventually may consume all of the leaf but the major veins.

Since these insects are not caterpillars (larvae of moths or butterflies), BT, found in Dipel and Thuricide will not be an effective treatment. However, a strong jet of water will dislodge the slugs and make it difficult for them to return to the plant. Other effective treatments include insecticidal soap, horticultural oils, spinosad (Fertilome Borer Bagworm, Leafminer and Tent Caterpillar Spray or Captain Jack’s Deadbug Brew) and permethrin (various trade names). (Ward Upham)

Contributors: Ward Upham, Extension Associate

0 Comments



Leave a Reply.

    Authors

    Ward Upham runs the Horticulture Response Center in the Department of Horticulture and Natural Resources at Kansas State University. Other contributors include K-State Extension Specialists.

    RSS Feed

      Subscribe to the newsletter by entering your e-mail and clicking the link below

    Subscribe

    Archives

    July 2022
    June 2022
    May 2022
    April 2022
    March 2022
    February 2022
    January 2022
    December 2021
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014

    Categories

    All
    All America Selections
    All-America Selections
    Amaryllis
    Anthracnose
    Ants
    Aphids
    Apples
    Apricots
    Army-cutworm-moths
    Ash-borer
    Ashes-in-the-garden
    Asparagus
    Bacterial-wilt
    Bagworms
    Bark-shedding
    Beans
    Bermudagrass
    Bird-feeding
    Bitter-cucumber
    Blackberries
    Blackspot
    Black-walnuts
    Blister Beetles
    Blossom End Rot
    Blossom-End Rot
    Blueberries
    Botryosphaeria
    Breaking-dormancy-early
    Breaking-dormancy-early
    Bristly Rose Slug
    Broccoli
    Brownheaded-ash-sawfly
    Brown-patch-on-fescue
    Brown-rot-of-fruit
    Budworms
    Buffalograss
    Bulbs
    Bulb Storage
    Butterflies
    Butterfly Gardening
    Cabbage
    Cabbage Worms
    Caddo Sugar Maples
    Calcareous
    Cantaloupe
    Carpenter Bees
    Cauliflower
    Cedar Apple Rust
    Cherry Leaf Spot
    Chickweed
    Chiggers
    Christmas Cacti
    Christmas Trees
    Cicada
    Cicada Killer Wasps
    Codling Moth Control
    Cold Frames
    Cole Crops
    Colorado Potato Beetle
    Columnar Trees
    Compost
    Conservation Trees
    Container Gardening
    Controlling Volunteer Trees
    Cool Season Vegetables
    Cool-Season Vegetables
    Core Aeration
    Corn Earworm
    Corn Gluten Meal
    Crabapples
    Crabgrass Control
    Crickets
    Crop Rotation
    Cucumber
    Cucumber Beetles
    Daylilies
    Deadheading Flowers
    Dormant-seeding-turfgrass
    Dothistroma Needle Blight
    Drip-irrigation
    Dr-seuss-gardening
    Dutch-elm-disease
    Early Blight
    Eggplant
    Elm Flea Weevil
    Elm Leaf Beetle
    Elm Pocket Gall
    Emerald Ash Borer
    Euonymus Scale
    European Pine Sawfly
    Excessive Rain
    Fall Armyworms
    Fall Colors
    Fall Gardening
    Fall Lawn Seeding
    Fall-webworm
    Family-heritage-gardening
    Fertilizing-cole-crops
    Fertilizing-flowers
    Fertilizing Lawns
    Field-bindweed
    Field Dodder
    Firewood
    Flatid Planthoppers
    Flooding
    Floral Arrangement Care
    Flourescent Lights
    Flowerbed Design
    Flowering
    Frost On Lawns
    Fruit
    Fruit Baskets
    Fruit Damage From Cold
    Fruit Trees
    Fungus Gnats
    Galls
    Garden Hoses
    Gardening Calendar
    Garden Seed
    Garden Spiders
    Garden Tool Care
    Garlic
    Goldenrod Soldier Beetle
    Grapes
    Grasshoppers
    Grass Seed
    Green June Beetles
    Growing Cuttings Inside
    Grubs
    Hackberry Caterpillar Butterflies
    Hackberry Psyllids
    Hardiness
    Harlequin Bug
    Harvesting
    Help For New Gardeners
    Henbit
    Herbicide Damage
    High PH Soils
    Holly
    Hollyhock
    Honeysuckle
    Hornworms
    Horseradish
    Houseplants
    Hydrangea
    Ice Melters
    Invasive Plants
    Iris
    Iron Chlorosis
    Irrigation
    Itch Mites
    Japanese Beetles
    Junipers
    Kansas Garden Guide
    Kentucky Bluegrass
    Knotweed
    Lacebugs
    Ladybird Beetles
    Landscape Design
    Lawn
    Lawn Calendar For Cool Season Grass
    Lawn Calendar For Cool-Season Grass
    Lawn Calendar For Warm Season Grass
    Lawnmower Care
    Lawn Seeding
    Leaf Scorch
    Leaves
    Lettuce
    Lilac
    Lilac Borers
    Little Barley
    Marcescence
    Maximizing Garden Space
    Melons
    Millipedes
    Mimosa Webworm
    Mole Control
    Mouse Damage
    Mowing
    Mulch
    Mums
    Mushrooms
    Mycosphaerella Leaf Spot
    Nantucket Pine Tip Moth
    Native Prairie Flowers
    Needle Drop On Conifers
    New Gardener Resources
    Nightcrawlers
    Nuts
    Oak
    Oak Leaf Itch Mite
    Onions
    Orchids
    Organic Matter
    Organic Sources Of Nitrogen
    Ornamental Grass
    Overseeding Lawns
    Overwintering Geraniums
    Paperwhite Bulbs
    Pawpaw Trees
    Peaches
    Pears
    Peas
    Peonies
    Peony
    Peppers
    Perennial Garden Clean Up
    Perennial Garden Clean-up
    Pesticide Effectiveness
    Pine Wilt
    Planting Calendar
    Plastic Mulch
    Plum
    Poinsettia
    Poison Ivy
    Poisonous Plants
    Pokeweed
    Poor Drainage
    Potatoes
    Powdery Mildew
    Powdery Mildew On Lawn
    Power Raking
    Propagating-woody-plants
    Prop Up Fruit Limbs
    Pruning
    Publications
    Quince
    Rabbits
    Raccoons
    Rain-barrels
    Raspberries
    Recommended-plants-for-ks
    Rhubarb
    Roasting Pumpkin Seeds
    Roots
    Rose
    Rose Rosette
    Roundup For Lawns
    Salad Garden
    Sawfly Larvae
    Scale
    Scale Insects
    Screen Trees
    Sedum
    Seed Germination
    Seed Germination
    Seed Tape
    Septoria Leaf Spot
    Shrub Pruning
    Shrubs
    Sidedressing
    Slime Molds
    Slugs
    Smut
    Soil
    Soil Preparation
    Soil Temperature
    Spider Mites
    Spiders
    Spirea Aphid
    Spittlebugs
    Spray Water PH
    Spreaders
    Spring Bulbs
    Spring Flowering Shrubs
    Squash
    Squash Bugs
    Squash Vine Borer
    Squirrel Damage
    Starting Seed
    Stink Bugs
    Storing Power Equipment
    Storm Damage
    Stratification
    Straw-bale-gardening
    Strawberries
    Succession Planting Of Vegetables
    Sunflowers
    Sunscald
    Survey
    Sweet Corn
    Sweet Potatoes
    Tall Fescue
    Tan/White Drupelets
    Termites
    Thatch Control
    Ticks
    Tomatoes
    Transplant Fertilization
    Tree Health
    Tree Leaves And Turf
    Tree Planting
    Trees
    Tubakia
    Tubakia-leaf-spot
    Turf-in-shade
    Twig-girdlers
    Vegetable-flowersfruit
    Vegetables
    Vegetable Seed
    Vegetable Transplants
    Velvet Ants
    Vinegar As Herbicide
    Walnut Caterpillars
    Warm Fall
    Water Damage
    Watering
    Watermelon
    Water Teepees
    Weeds In Flower Beds
    Weeds In Turf
    Weird Squash
    White Grubs
    Whitelined-sphinx-caterpillar
    Wildflower Establishment
    Wildflower-establishment
    Wildlife
    Wild Violet Control
    Wind Chill
    Winter Damage
    Winterizing Water Lines
    Winter Mulching Vegetables
    Winter Squash
    Wood Chips
    Worms From Oaks
    Yellowjackets
    Yellow Nutsedge

Powered by Create your own unique website with customizable templates.