Horticulture 2023 Newsletter  No. 40 

Horticulture News

Blog Post: http://www.ksuhortnewsletter.org
Video of the Week: How to Test Your Soil for Nutrients
Kansas Forest Service Tree, Shrub Seedling Sale, September 1 – October 15
Kansas Turf & Landscape Conference
The 73rd Annual Kansas Turf & Landscape Conference will be held on Wednesday, November 29 and Thursday, November 30 at the Hilton Garden Inn, Manhattan. The conference is an excellent way to learn about turf and landscape management, visit with old friends, network with new ones, and see all the latest products and supplies from local and national vendors.
The conference has been approved for commercial pesticide recertification hours:
1 Core hour
3A – 7 hours
3B – 7hours
GCSAA education points and International Society of Arboriculture CEUS will also be available by attending the conference.
For more information, go to https://www.kansasturfgrassfoundation.com/
• Add organic matter to vegetable garden this fall.
• Bring houseplants in if you haven’t already.
• Dig sweet potatoes
Pruning Trees and Shrubs in the Fall
Woody plants are actively building up their storage of sugars as they approach leaf drop. Pruning in the fall limits this process and reduces the amount of energy the plants have available through dormancy. Woody plants pruned this time of year may also send out new growth which is unlikely to be hardy enough to survive the winter.
With the exception of removing dead or diseased branches and “light” pruning, it is best to save this garden task for next year. Pruning is considered “light” if 10% or less of the plant is removed. For shrubs that bloom in spring, even light pruning in the fall can reduce flowering. It is best to prune spring-flowering shrubs, such as forsythia, lilac, flowering quince, almond, beautybush, deutzia, pyracantha, mock orange, cotoneaster, weigela, viburnum and witchhazel after they bloom.
Summer-blooming shrubs, such as hydrangea, rose of Sharon, butterfly bush and crepe myrtle, can be pruned in early spring because the blooms are set on the new growth. With a few exceptions, most deciduous trees respond best to late winter/early spring pruning. This practice allows gardeners a better view of the cuts since the trees are dormant and it allows the trees to enter dormancy healthy, without the increased stressed from pruning. (Cynthia Domenghini)
Clean up Iris Beds this Fall
To prevent overwintering of iris borers and the fungus, iris leaf spot, remove and clean up dead leaves from iris plants now. Iris borer eggs and iris leaf spot survive in plant debris through the winter and reappear the next growing season. Removing debris from the garden is an effective control against these pests. Healthy iris leaves can be cut back to one-half their size. (Cynthia Domenghini)
Plant Identification Help
We often receive questions related to identifying landscape plants. There are many smart phone apps available that can sometimes accurately identify plants through photos. Your local extension agency is a great resource, especially if you provide a complete plant sample for identification. Here are some items to consider as you prepare a sample for your agency whether for identification of the plant itself or to help diagnose causes of damage.
     Live Plant Sample:
• For small plants, include as much as possible: roots, stems, leaves, flowers and fruits.
• Gently shake loose soil from the roots but do not wash roots.
• Prevent wilting by placing roots in a plastic bag and keep them moist.
• Stems, leaves and other above-ground growth can be covered in newspaper, not plastic.
• Harvest the sample as close to the day you will deliver it as possible.
• For trees, shrubs and vines include a branch, approximately one- to two-feet in length, with several buds/leaves.
• Store plant sample(s) in a box in a cool, dark location until it is delivered to prevent wilt.
Photo Submissions:
• Include a photo of the entire plant and growing site.
• Include a photo of the leaves, stems, buds, fruit and flowers up close.
• Show how large the plant parts are by including a scaling item, such as a ruler, next to the plant part(s).
• Ensure photos are in-focus.
• If plant has symptoms of disease or pest damage, include images of healthy and unhealthy plant material.
• Include a photo of the plant against a solid background so the plant stands out. Examples of background could be a piece of paper or your hand.
      Sending in photos to accompany a live sample is a great way to show the surroundings where the specimen is growing and can aide in identification. In general, include enough information in your plant sample, whether live or digital, to tell a complete story for the best chance of accurate identification. (Cynthia Domenghini)
 Fall is a Good Time for Soil Testing
Soil tests are useful tools to evaluate the basic fertility of the soil. They do not provide information on soil composition, compaction, contamination or diseases and pests. Although each of these problems affect plant growth, establishing balanced nutrients in the soil is essential for a healthy lawn and garden.
Collect uniform soil from six spots within each area that needs to be tested. Uniform soil will have the same texture, color and history of growing and fertilization practices. Areas that are not similar should be tested separately. For example, soil from the lawn should be tested separately from soil in the garden. Use a soil probe, or shovel if probe is not available, to dig six- to eight-inches straight down into the soil. Shave a layer of the soil off the inside of the hole in each of the six spots and mix these collections thoroughly in a clean bucket, removing any debris.
Scoop a total of 1.5 to 2 cups of mixed soil into a plastic container such as a resealable bag. Repeat this process for each unique area that needs to be evaluated. Label the samples with the location where they were gathered. Complete online paperwork as applicable for your extension office and include it with your sample delivery.
Soil testing in the fall allows you to sample the soil when it is less likely to be waterlogged. Additionally, more organic material is available to integrate into the soil in case the test results indicate this is necessary. Soil test laboratories are typically busier in the spring, so get a jump start on this task now to save yourself from delays next year. (Cynthia Domenghini)
Seed Stratification for Trees
There are several considerations to make when attempting to grow trees such as sycamores, oaks and sugar maples from seed. Seed maturity and dormancy will affect the germination rate of most cultivated trees. To overcome problems caused by seed immaturity simply wait for the seeds to develop completely prior to planting. Dormancy involves a few extra steps to prepare seeds for germination.
      Seeds that are dormant will not germinate even when conditions are favorable. To break dormancy and promote germination, the seeds should be exposed to the temperature and moisture experienced in their natural environment for the required length of time. This process is called, “stratification.” The temperature and length of stratification time varies depending on the tree species. Typically, seeds that drop in early fall need a warmer stratification period while those that drop later in the fall need cooler temperatures. In Kansas it is more common for seeds to require cool, moist stratification conditions. Temperatures between 35- and 45-degrees F are best for cool stratification. If unsure about the length of stratification, three to four months should be sufficient.
      Stratify seeds in a moist medium. Dry conditions will not allow the seeds access to the necessary water, but waterlogged medium will reduce the amount of oxygen available to the seeds. Peat moss is a good option and can be used at a ratio of 1-part water to 1-part peat moss (by weight). Use warm water to moisten the peat moss so it is absorbed more quickly.
      Place small quantities of seeds in moist peat moss and store in the refrigerator in a plastic bag. If the seeds are small they can first be wrapped in between sheets of cheesecloth so they aren’t lost in the peat moss. Larger quantities of seeds can be stratified between layers of moist sand or a moist sand/peat moss mix. Bury the container outside so the top of the container is level with the soil surface. Cover the top with leaves or straw. Alternatively, the container can be stored through the winter in an unheated garage or cellar. (Cynthia Domenghini)
Using Silt from a Pond
If you’re someone who took advantage of the drought and cleaned out your farm pond you may be wondering what to do with the silt left behind. Silt can be used as a fill dirt, but exercise caution when using it for planting.
      Pond silt has very few large pore spaces which is problematic in the garden. Pore space is essential for plant growth as this is how water soaks into the root zone and the way oxygen reaches deep into the soil. Limited pore space, or soil compaction, translates to problems in every stage of plant growth. Fortunately, we can rebuild the soil structure by adding organic matter. Doing this now will prepare the silt for spring planting. Add two inches of rotten hay, rotted silage, leaf mold, peat moss or other organic matter to the surface of the silt and mix it thoroughly to promote decomposition.
      Another issue with using silt for growing is the lack of nutrients. To remedy this problem, incorporate a complete, balanced fertilizer prior to planting. Ideally you should add one pound of actual nitrogen per 1,000 square feet. For example, with a 13-13-13 fertilizer add about 7.5 pounds per 1,000 square feet. (Cynthia Domenghini)
Cynthia Domenghini, Instructor and Horticulture Extension Specialist
Ward Upham, Extension Associate
Department of Horticulture and Natural Resources
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173
For questions or further information, contact: [email protected], [email protected] OR [email protected]
This newsletter is also available on the World Wide Web at:
The web version includes color images that illustrate subjects discussed. To subscribe to this newsletter electronically, send an e-mail message to [email protected], [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.
Kansas State University Agricultural Experiment Station and Cooperative Extension Service K-State Research and Extension is an equal opportunity employer.  Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended. Kansas State University, County Extension Councils, and United States Department of Agriculture Cooperating, Ernie Minton, Dean.
Cynthia Domenghini, Ph.D.
Instructor and Horticulture Extension Specialist
Department of Horticulture and Natural Resources
Kansas State University
Manhattan, KS 66506


Please enter your comment!
Please enter your name here