Horticulture 2022 Newsletter No. 23

Horticulture News



Blog Post: http://www.ksuhortnewsletter.org

Video of the Week: Buffalograss: Fertilizing and Mowing

Turn compost pile after it cools
Deadhead flowers. https://tinyurl.com/y7vhao7x
Remove flower stalks from peonies and iris.
Fertilize warm-season lawns such as zoysia, bermuda and buffalo.

New Potatoes
Many gardeners look forward to harvesting new potatoes at this time of year. New potatoes are immature and should be about the size of walnuts. Pull soil away from the base of the plants to see if the tubers are the desired size. If they are, dig entire plants and allow the skins of the exposed tubers to dry for several hours before gathering. These young potatoes are very tender and prone to the skin “slipping” unless they are given a few hours to dry. Even then these immature potatoes will not store well. Red-skinned varieties are often preferred as they are the earliest to produce. (Ward Upham)

Do Not Over-Fertilize Tomatoes
Though tomatoes need to be fertilized to yield well, too much nitrogen can result in large plants with little to no fruit. Tomatoes should be fertilized before planting and sidedressed with a nitrogen fertilizer three times during the season.
The first sidedressing should go down one to two weeks before the first tomato ripens. The second should be applied two weeks after the first tomato ripens and the third one month after the second. Common sources of nitrogen-only fertilizers include nitrate of soda, urea, and ammonium sulfate. Blood meal is an organic fertilizer that contains primarily, but not exclusively, nitrogen. Use only one of the listed fertilizers and apply at the rate given below.
Nitrate of soda (16-0-0): Apply 2/3 pound (1.5 cups) fertilizer per 30 feet of row.
Blood Meal (12-1.5-.6): Apply 14 ounces (1.75 cups) fertilizer per 30 feet of row.
Urea (46-0-0): Apply 4 ounces (½ cup) fertilizer per 30 feet of row.
Ammonium Sulfate (21-0-0): Apply 0.5 pounds (1 cup) fertilizer per 30 feet of row.

If you cannot find the above materials, you can use a lawn fertilizer that is about 30 percent nitrogen (nitrogen is the first number in the set of three) and apply it at the rate of 1/3 pound (3/4 cup) per 30 feet of row. Do not use a fertilizer that contains a weed killer or weed preventer. (Ward Upham)

Fruit Reminders
Fruit gardens have certain chores that need to be done through the growing season such as the following.
* Remove some fruit from heavily loaded apples and peaches (if the flower buds weren’t killed by frost) to improve fruit size and prevent limbs from breaking. Apples and peaches should be spaced about every 6 to 8 inches. Note that is an average spacing. Two fruit can be closer together if the average is correct.
* Remove sucker growth from the base of fruit trees and grape vines.
* Remove water sprout growth from fruit trees. Water sprouts grow straight up from existing branches.
* Water as needed. About 1 inch of water per week is about right though more may be needed during hot spells.
* “Comb” new growth on grape vines so these new shoots hang down for greater exposure to sunlight.
* Continue disease and insect control to prevent fruit damage. For more detail on fruit sprays, see “Spray Schedules” on our publication page. (Ward Upham)

How Healthy is My Tree?
One of the most important clues in determining the health of your trees is the amount of new growth that tree produces. A healthy tree should have a minimum of 4 to 6 inches of new growth each year. Check branches with the tips in the open and not shaded by the tree itself. Anything less than 4 inches on the majority of branches suggests the tree is under a great deal of stress.
So how do you tell where the new growth stops? Look for a color change in the stem. New growth is often greener than that from the previous year. There is also often an area of what looks like compressed growth where growth transitions from one year to the next.
Lastly, look at leaf attachment. Leaves are only produced on current season’s growth. Therefore, new growth stops where leaves are no longer attached directly to the twig but to side branches. However, pay attention as leaves may be appear to be attached directly to last year’s growth but are actually borne on short spurs. If you look closely, you can tell the difference.
All this clue tells you is whether a tree is under stress or not. It does not tell you what is causing poor growth. Stress is cumulative. In other words, trees may not have completely recovered from stressful conditions (such as drought) that occurred within the last several years. The accumulating stress may have damaged root systems with further damage occurring due to the dry soils last fall and winter. These trees may struggle as we enter summer. Though the roots were able to keep up with moisture demands during the cooler spring weather, they may not be able to as temperatures rise. Such trees may suddenly collapse and die or slough off branches they can no longer support. If possible, water to a depth of 12 inches every couple of weeks we do not receive rain in order to avoid further stress. (Ward Upham)

Look for Bagworms Now
Most calls on how to control bagworms come in during late-July to early-August when damage appears. Bagworms are difficult to control when they are that large. They are much easier to kill while small.

Bagworms overwinter as eggs inside the dead female’s bag. Young larvae normally hatch and emerge during mid- to late-May in Kansas. Now would be a good time to scout for bagworms. Wait to use control measures until mid-June as earlier sprays may miss those who emerge from the bag later than normal. However, make sure the bagworms are present by looking for a miniature version of the mature bagworm. Also, check to be sure the bagworms are alive before spraying. Predators and parasites can sometimes naturally control this pest.

Insecticides commonly used for controlling bagworms include:
acephate (Orthene)
permethrin (38 Plus Turf, Termite & Ornamental Insect Spray; Eight Vegetable, Fruit & Flower Concentrate; Garden and Farm Insect Control )
bifenthrin (Bug Blaster II, Bug-B-Gon Max Lawn and Garden Insect Killer)
lambda-cyhalothrin (Spectracide Triazicide, Bonide Caterpillar Killer)
spinosad (Conserve; Natural Guard Spinosad; and Captain Jack’s Dead Bug Brew).
Spinosad is an organic control that is very effective on this pest. Thorough spray coverage of foliage is essential for good control with any of these products. (Ward Upham)

Slime Molds
Slime molds are primitive organisms that are common on turf and mulch and sometimes on tree trunks. Slime molds are not fungi and are no longer classified as such. They belong to the Kingdom Protista rather than Kingdom Fungi. On turf, you might often see large numbers of small gray, white or purple fruiting structures, called sporangia on leaf blades during cool and humid weather throughout spring, summer, and fall. Affected areas are often several inches to 1 foot in diameter. During wet weather, the fruiting structures may appear slimy. As the structures dry out in hot weather, they become ash gray and break up easily when touched.

Homeowners often are concerned that this is a disease organism that will kill the grass, but slime mold feeds on bacteria, other fungi, and dead organic matter. It simply uses the turf as a structure on which to grow. However, slime mold can damage turf by completely covering leaf blades and interfering with photosynthesis. Chemical control of slime molds is not necessary. Use a broom or a heavy spray of water to dislodge the mold.

Slime molds on mulch often attract attention because of their bright colors and disgusting appearance. Common names are often quite descriptive. For example, the “dog vomit” slime mold is a bright, whitish color that resembles its namesake. It eventually turns brown and then into a hard, white mass. There is also the “scrambled egg” slime mold, “the yellow blob” slime mold and the “regurgitated cat breakfast” slime mold. Slime molds do not hurt anything, but most people do not find them attractive and want to get rid of them. Simply use a shovel to discard the offensive organism and then stir up the mulch for aeration. (Ward Upham)

After-Effects of Too Much Rain
Many areas of Kansas have had saturated or near-saturated soils for some time now. Gardeners are likely to assume that watering won’t be needed for quite some time after dry weather arrives due to such high soil moisture levels. Actually, watering may be needed much sooner than you expect.

Excessive rain can drive oxygen out of the soil and literally drown roots. Therefore, as we enter hotter, drier weather, the plants with damaged root systems may be very susceptible to a lack of water. Don’t forget to check your plants for signs of wilting or leaf scorching and water as needed.

If irrigation is called for, water deeply and infrequently. Usually once per week is sufficient depending on the weather. Soil should be moist but not waterlogged. (Ward Upham)

Inexpensive Method of Watering Trees
We covered this a couple of weeks ago when discussing flooding damage but it bears repeating. One of the more common means of water watering trees is the use of soaker hoses. Soaker hoses are notorious for non-uniform watering. In other words, you often receive too much water from one part of the hose and not enough from another. On small trees, circling the tree several times with the soaker hose will even out the amount of water applied but this isn’t practical for larger trees. On larger trees, hooking both the beginning and the end of the soaker hose to a Y-adapter helps equalize the pressure and therefore provide a more uniform watering. The specific parts you need are shown in the photo above and include the soaker hose, Y-adapter and female to female connector.

It is also helpful if the Y-adapter has shut off valves so the volume of flow can be controlled at the hose. Too high a flow rate can allow water to run off rather than soak in.
The soaker hose can circle the trunk at a distance within the dripline of the tree but at least ½ the distance to the dripline. The dripline of the tree is outermost reach of the branches. On smaller trees, you may circle the tree several times so that only soil which has tree roots will be watered.

Soil should be wet at least 12 inches deep as 80% of a trees roots are in the top foot of soil. Use a metal rod, wooden dowel, electric fence post or something similar to check depth. Dry soil is much harder to push through than wet and your probe will stop when it hits dry soil. How long it takes water to reach a 12 inch depth varies depending on the rate of water flow and soil. Record the amount of time it takes to reach 12 inches the first time the tree is watered. After that, simply water for that same amount of time. (Ward Upham)

Contributors: Ward Upham, Extension Associate

Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173

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