1712 Claflin, 2021 Throckmorton Plant Science Center
Manhattan, KS 66506 (785) 532-6173
Online PDF access
Video of the Week: Heat Loving Perennials
(May 2025 K-State Garden Hour Webinar Recording)
Learn tips to select and care for low maintenance, drought tolerant plants that add color and texture to your landscape
ANNOUNCEMENTS
Upcoming K-State Garden Hour
Wednesday, June 4, 2025 12:00-1:00 PM
Register HERE
Join Johnson County Horticulture Extension Agent, Markis Hill, to learn more about Kansas native and ornamental grasses.
Kansas Turf & Ornamentals Field Day
The Kansas Turf & Ornamentals Field Day will be held on Thursday, August 7, 2025 at the Rocky Ford Turfgrass Research Center in Manhattan.
This Field Day program is designed for all segments of the turf & ornamentals industry — lawn care, athletic fields, golf courses, sod farms, landscape, nursery, and grounds maintenance. Included on the program are research presentations, problem diagnosis, commercial exhibits, and equipment displays. There will be time to see current research, talk to the experts, and get the answers to your questions.
For more information and to register online, go to: www.kansasturfgrassfoundation.com
We hope to see you on August 7 in Manhattan!
Commemorating Dr. Chuck Marr
Dr. Chuck Marr served as a Vegetable Crop Specialist for K-State Research and Extension for 36 years. He was an active member of the community and supported gardeners in many capacities throughout his retirement as well.
Chuck passed away in December of 2024. To honor the legacy of Chuck, many of his friends are coming together to designate a special area in the Kansas State University Gardens in his name. The Riley County Extension Master Gardeners and the Manhattan Watercolor Group are leading this meaningful tribute and warmly invite others to participate.
Chuck was a strong advocate for the Gardens on campus. We envision dedicating the main vegetable growing bed in the Gardens in Chuck’s honor. This space, where he spent so much time nurturing plants and educating others, would be a fitting tribute.
The sponsorship level for this area is $15,000. We hope to raise the total amount collected by July 15 to ensure recognition in the Gardens. If you would like to contribute, donations can be made to Kansas State University Foundation in the following ways:
Online: Donation · Kansas State University · GiveCampus
By phone: 785-775-2400
By mail: Send checks payable to:
Kansas State University Foundation
1800 Kimball Ave., Suite 200
Manhattan, KS 66502 Please include Fund # M47497 (Chuck Marr) in the memo
Thank you for considering this request in memory of Dr. Chuck Marr. If you have any questions or would like additional information, please feel free to reach out to Riley County Extension Agent, Gregg Eyestone at 785-410-5336 or [email protected].
GARDEN CALENDAR
May Garden Calendar
VEGETABLES
Onions Developing
Nitrogen fertilizer will support healthy plant development above ground which directly relates to onion bulb growth.
Here are some guidelines for fertilizer rates:
Ammonium sulfate (21-0-0) at a rate of ½ cup per 10 feet
29-5-5 or 27-3-3 can be used at a rate of 1/3 cup per 10 feet
Apply the fertilizer two to three inches away from the plants and water it in. Stop fertilizing when bulbs begin to emerge through the soil. Do not mound soil over the bulbs.
Weed regularly to reduce competition for water, nutrients and space. The amount of water and space the bulbs have available will affect the size of the bulbs. Provide regular water during drought.
FRUIT
Thinning Fruit
Allowing fruit trees to produce a heavy crop, especially on a young tree, can cause damage to the branches from the weight, and reduce the size of the fruit this year. By thinning the fruit, trees will be prepared to produce a healthier harvest in subsequent years.
The guidelines that follow can help you determine which fruit to remove and which to leave intact.
Apples and Pears: Allow 6-8 inches between fruit. Apple trees tend to produce fruit in clusters of five. Remove all but one fruit from each cluster. Leave the largest, healthiest fruit.
Peaches: Allow 6-8 inches between fruit.
Plums and Prunes: Space fruit 4-5 inches apart.
Apricots: Space fruit 2-4 inches apart.
Fruit can be removed by snipping with clippers or snapping the fruit stem with your fingers. Be careful not to damage the branch.
Tip Blackberries, Black Raspberries and Purple Raspberries
Raspberries and blackberries have similar growing and fruiting habits. The perennial root system grows for several years. The canes are biennial (live for two years).
The first-year canes are called primocanes and do not produce fruit. The second year, the primocanes become floricanes which fruit and then die. Primocanes are produced each year so plants have both types of canes present simultaneously.
Primocanes should be tipped by removing the top two to three inches to promote branching and fruiting.
The species and fruiting habits of the plant determines how the plant should be tipped. Plants that fruit on primocanes are referred to as “everbearing”. Plants that produce fruit only the second year are called “traditional”.
Here are guidelines for tipping blackberries and raspberries:
Traditional blackberries: tip at 4 feet
Everbearing blackberries: tip at 25-30 inches; tip laterals at 25-30 inches as well
Black Raspberries: tip at 3 feet
Purple Raspberries: tip at 36-40 inches
Red Raspberries: do not tip
TURF
Aerate Warm-Season Grasses
Roots make up 90 percent of grass plants and need oxygen for survival. Compacted soil restricts the roots’ access to oxygen and inhibits growth. Aeration loosens the soil, allows air to enter and provides better infiltration of water and nutrients. All of this promotes healthier root growth and consequently, healthier grass.
Core aeration is done with a machine that uses hollow tines to remove plugs of soil leaving holes that are two to three inches deep. Multiple passes may need to be done in order to get the holes three inches apart.
Bermudagrass, buffalograss and zoysiagrass tend to require aeration more frequently than bluegrass and fescue. Clay soils and lawns with heavy traffic may require aerating twice a year. Warm-season grasses should be aerated from late May through July. It is recommended to have a professional aerate your lawn because the procedure requires heavy duty equipment to penetrate the soil.
Little Barley in Lawns
Little barley (Hordeum pusillum) is often confused with foxtails because of the seedheads that form on the bunch grass from spring through summer. However, little barley is a winter annual and foxtails are a summer annual. The seedheads don’t develop on foxtails until mid to late summer.
Little barley is commonly found in disturbed areas such as roadsides, overgrazed pastures and thin lawns. Maintaining a dense, healthy lawn is the best defense. Overseed sparse lawns in late August to early September or use a preemergent. Mow the lawn on a higher setting to prevent sunlight from reaching the soil.
QUESTION of the WEEK
Brown-headed Ash Sawfly
What is this caterpillar eating my ash tree?
(Contributed by Dr. Ray Cloyd)
We have received several inquiries regarding caterpillar like insects feeding on green ash (Fraxinus pennsylvanica) trees. The insects in question are larvae of the brown-headed ash sawfly, Tomostethus multicinctus, which are sporadic, early season, defoliating insect pests. The larvae feed extensively causing noticeable leaf damage and producing frass or fecal material.
Brown-headed ash sawfly larvae are approximately 15 to 20 millimeters (1/2 to 3/4 of an inch) long, yellow green, with white and green stripes extending the length of the body (Figure 1). The larvae have a brown head, and there are prolegs (fleshy, leg like appendages) on every segment of the body, which distinguishes sawfly larvae from caterpillars. Brown-headed ash sawfly larvae feed primarily on green and white ash trees. Adults are wasp like in appearance. Brown-headed ash sawfly pupate in the spring, with adults emerging and females laying eggs inside leaves. Larvae emerge (eclose) from eggs and congregate in groups, feeding from May through June.
Larvae create shot holes or pin holes on young leaves (Figure 2), but as they increase in size, the larvae consume entire leaves, especially terminal leaves (except the main veins), resulting in almost complete defoliation. By June, larvae are fully grown and shed a papery like skin that is attached to the leaf (Figure 3). The larvae move toward the base of the tree and construct protective cocoons. High numbers of larvae may be present at the base of trees (Figure 4). Brown-headed ash sawfly overwinter as full-grown larvae or pre pupae within silken lined cells located on the top of the soil at the base of previously infested trees. There is one generation per year in Kansas.
Rainfall will quickly remove larvae from trees. In addition, the larvae can be removed by hand and placed into a container of soapy water to kill them. An insecticide application is not warranted unless brown-headed ash sawfly larval populations are causing extensive damage that compromises the aesthetic value of an ash tree. Insecticides with contact activity can be applied, but thorough coverage of the tree canopy, in particularly, the leaf undersides, is important. Do not apply an insecticide containing the active ingredient, Bacillus thuringiensis subsp. kurstaki, because the product will not kill sawfly larvae.
For more information on brown-headed ash sawfly, you can access the following extension publication:
Cloyd, R. A. 2016. Brown-headed ash sawfly. Kansas State University
Agricultural Experiment Station and Cooperative Extension Service. Kansas State University; Manhattan, KS. MF3297. 2 pages.
http://www.bookstore.ksre.ksu.edu/pubs/MF3297.pdf
Contributors:
Cynthia Domenghini, Instructor and Horticulture Extension Specialist
Ray Cloyd, Entomology Extension Specialist
Kansas Garden Guide
KSRE Entomology
Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173
For questions or further information, contact: [email protected].
This newsletter is also available online 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].
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
[email protected]
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