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HNR Website access: https://hnr.k-state.edu/extension/horticulture-resource-center/horticulture-newsletter/
1712 Claflin, 2021 Throckmorton Plant Science Center
Manhattan, KS 66506 (785) 532-6173
ANNOUNCEMENTS
K-State Garden Hour
Establishing a More Environmentally Sustainable Lawn
Wednesday, August 1st from noon to 1:00 PM (CST)
Whether you are interested in reducing your water bill or supporting pollinators, there are alternatives to growing and maintaining typical turfgrass lawns. Sharon Ashworth, Douglas County Horticulture Extension Agent, will discuss reducing the water, herbicides and fertilizers used on fescue lawns and replacing fescue grass with low-growing alternatives that support our pollinators.
Register for the free, live Zoom webinar here: https://hnr.k-state.edu/extension/consumer-horticulture/garden-hour/
2024 Kansas Turf and Ornamentals Field Day
August 1, 2024, at Rocky Ford Turfgrass Research Center in Manhattan, KS. https://www.k-state.edu/turf/events/2024TurfFieldDayProgram.pdf
VIDEO OF THE WEEK:
Dividing Irises
GARDEN TO-DO
Remove sucker growth and watersprouts from fruit trees
Prepare to plant the fall garden – avoid deep tilling
Mid-August direct seed: leafy lettuce varieties, beets, mustard, arugula, Swiss chard, kale, turnips, radishes, green onions, Bok choy
VEGETABLES
Green Beans Producing Flowers but not Beans
Temperature is a key factor affecting bean production. High (above 85 degrees F) and low (below 70 degrees F) can cause plants to create flowers but not beans. Inconsistent soil moisture can also inhibit bean development and is exacerbated by hot, dry winds.
Proper crop management is the best way to mitigate these problems. Mulch surrounding plants regulates soil temperature and moisture. Using a windbreak crop, such as corn, can protect the bean plants from drying winds. Harvest regularly to encourage plants to continue producing. If beans are left on the plant past their peak harvest time the plant will use energy to produce seed rather than create new beans.
FRUIT
Watering Fruit Plants During Summer
Ensure fruit trees are receiving adequate water to get the best harvest. Heat and drought stress restrict cell division which affects the size of the mature fruit even if water is added later. It can also lead to leaf wilt and discoloration as well as leaf and fruit drop. Bud development for next year’s crop could also be hindered.
Monitor the soil at the rootzone to prevent problems. A wooden dowel or metal rod can be used to probe the soil. If it is difficult to insert the probe 8-12 inches the soil is likely too dry. Add water to the rootzone slowly. Test with a probe again and once it can reach 12 inches easily, the moisture level should be adequate.
When the weather is hot and dry, monitor the fruit plants. Moisture level of newly planted and shallow-rooted crops should be checked at least twice a week.
TURF
Crabgrass Control
Crabgrass is a common weed in lawns this time of year particularly in sparse lawns. The blades of this warm-season, annual are flat, wide and lighter green than the desired turfgrass. Crabgrass dies back after setting seed or the first frost leaving bare spots in the lawn. At that time cool-season grasses should begin to flourish and fill in the spaces. If you have crabgrass in your lawn now you can expect it again next year since it is so efficient at re-seeding.
Preventing crabgrass from establishing in the lawn is the best method of control. Maintain a thick, healthy lawn to stop crabgrass seeds from germinating. Mow your lawn no shorter than three-inches to help prevent sunlight from reaching the seeds on the soil surface. Pre-emergence can be used in spring.
At this point in the season, it is too late for a crabgrass preventer. Manually removing crabgrass plants is recommended for small areas and light infestations. There are some herbicides that will kill crabgrass including: Ortho Weed-B-Gon Max + Crabgrass Control, Fertilome Weed-Out with Crabgrass Control, Monterey Crab-ERad and BioAdvanced Lawn Weed & Crabgrass Killer. Each of these contains quinclorac, which is a crabgrass herbicide, as well as other active ingredients that control broadleaf weeds. Quinclorac can also provide control for foxtail and certain other broadleaf weeds such as field bindweed, black medic and clover. Be sure to bag your clippings if you use a crabgrass killer and don’t use them as mulch or compost.
Summer Watering for the Lawn
Buffalograss is a drought-tolerant grass and often survives summers without regular watering. Bermudagrass and zoysiagrass require less water during stressful summers than cool-season species. The recommended approach for watering established lawns is to wait for signs of general drought stress, and then apply sufficient water to moisten the soil to the depth of the root system. Established turfgrass indicates drought stress by turning a dull, blue-green color. When you walk on drought stressed grass it tends to stay flattened rather than popping back upright.
Use a screwdriver or metal rod to determine how deeply water has penetrated the soil. Push the tool into the ground until you reach dry soil. The tool will pass easily through moist soil but will stop when it comes in contact with dry ground. Remove the tool from the soil and measure to determine depth of watering.
An established tall fescue or Kentucky bluegrass lawn has the capacity to enter a dormant condition when under drought stress and may survive several weeks or more without water. After that, it’s important to provide ¼ inch of water, if rainfall is insufficient, every couple of weeks to keep the crowns alive. With this approach, properly maintained, established bluegrass and fescue lawns, growing on good soil, can survive up to eight weeks without substantial irrigation.
Note: Because early fall is the time to perform important cultural practices on cool-season lawns such as fertilization, core aeration, and overseeding, it is wise to water dormant lawns deeply in mid to late August to establish the soil’s moisture reserve and revive dormant lawns so they can respond to these practices.
MISCELLANEOUS
Prioritizing Water in the Landscape
During periods of drought, it may be necessary to prioritize which plants will be first to receive supplemental water due to city-imposed water restrictions, cost and time.
Start with the large, established trees. These are the most difficult and expensive to replace if they don’t survive. They also take the longest to become established. While they may not require supplemental water during a short drought period, if prolonged established trees can suffer. Next, care for the young trees which are still developing their root systems.
Shrubs come next, followed by perennials, lawn and finally, annuals. This order will direct your attention to the plants that have had the most invested in them saving you time and money if you must replace plants that don’t survive. See below for tips to increase watering efficiency.
Watering Young Trees and Shrubs
Young trees and shrubs have not established the root system necessary to survive extreme heat and dry spells without supplemental water. After planting, it is essential to keep the root ball area moist for several weeks, but even a couple years later it may be necessary to periodically apply water to the area. Newly planted trees should receive 10 gallons of water weekly. Here are some tips for watering to eliminate waste and meet plant needs.
Direct water where it is needed (avoid watering hardscapes!)
Do not water on windy days
Water between 6 PM and 10 AM to reduce evaporation
Assess soil moisture before adding water to the landscape
Apply the water slowly so it can sink deep into the root zone
Build a reservoir (three to four-inches tall) around trees to keep the water in the desired area.
Use a water bag, or five-gallon bucket with a 1/8-inch hole drilled in the base, to direct water to the base of trees.
Mulch around plants to retain moisture and moderate soil temperature
Understand water requirements of your plants. Provide water to plants only if needed, not based on a schedule.
Cicada Killer Wasps
Description: At about 1 ½-inches long, cicada killers are an intimidating wasp. They have reddish colored wings and legs and a black abdomen with wide, yellow stripes. Cicada killers live independently though nests may be relatively close to each other. Females have a stinger which is used to paralyze their prey. They rarely sting people unless agitated. Males are smaller and do not have a stinger.
The female wasp is responsible for locating cicadas and paralyzing them with her stinger. She then carries the cicada back to her burrow. Each burrow can house up to 20 cicadas.
Life Cycle: Adult females lay a single egg on each cicada they drag into the ground. Eggs hatch in two to three days into legless, white grubs which feed on the cicada. The larvae then create a protective case in which to overwinter. Adult wasps die in early fall. In spring the larvae pupate in the pupal cases and emerge as adults in June/July. There is one generation per year of cicada killers.
Damage: Cicada killers typically cause very little damage to the landscape. A heavy infestation may become a nuisance as they protect their nests. The burrows may be considered unsightly, especially in a lawn area.
Control: Cicada killers prefer well-drained, light soils in full sun. They may burrow along sidewalks or flowerbeds but do not like areas covered with mulch. Maintaining a thick, healthy lawn is the best control for preventing burrows. Pesticides are not usually necessary since adults are only present for about two months beginning mid to late summer.
SCHOOL GARDEN CONTENT
Fall Gardening at School
Students are heading back to the classroom and they’re just in time to plan and plant the fall garden. This doesn’t have to be a monumental feat. With a single container, students can have a meaningful hands-on learning experience and some tasty veggies too!
Read more about Fall Gardening at School (KSRE publication).
QUESTION of the WEEK
Is rock mulch the same as organic mulch?
We have some mature trees under which nothing much grows. If we put rocks around the tree but not right up to the trunk–is this okay?
One benefit of rock mulch is it doesn’t need to be replaced as frequently as bark since it doesn’t break down. This is also a disadvantage since it doesn’t contribute to soil improvement as organic mulches do. If you’re going to use rocks as mulch, they need to be small, such as pea gravel. Rock mulch can generate more heat, so ensure this is a good fit for the landscape plants. Consider organic options and select the best mulch for your growing conditions. Larger rocks such as river rock or cobblestones can be nice decorative elements in a landscape, but should not be used as mulch.
Contributors:
Cynthia Domenghini, Instructor and Horticulture Extension Specialist
K-State Turfgrass
Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173
For questions or further information, contact your local extension agency.
This newsletter is also available on the World Wide Web at:
http://hnr.k-state.edu/extension/info-center/newsletters/index.html
The web version includes color images that illustrate subjects discussed. To subscribe to this newsletter electronically, send an e-mail message to [email protected] or [email protected] listing your e-mail address in the message.
Brand names appearing in this newsletter are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned.
K-State Research and Extension is committed to making its services, activities and programs accessible to all participants. If you have special requirements due to a physical, vision or hearing disability, or a dietary restriction please contact Extension Horticulture at (785) 532-6173.
Cynthia Domenghini, Ph.D.
Instructor; Horticulture Extension Specialist
Department of Horticulture and Natural Resources
Kansas State University
1712 Claflin Rd.
Manhattan, KS 66503
785-340-3013
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