Extension

Controlling Broadleaf Winter Weeds in Home Lawns

David Hillock

 

Winter weeds such as dandelions and clover in bermudagrass, Kentucky bluegrass, centipedegrass, perennial ryegrass, tall fescue, and zoysiagrass can be controlled in November with products containing 2,4-D, dicamba, and MCPP combinations. Air temperatures should be above 50°F for best control. Examples of commonly found winter annual broadleaf weeds include chickweed, dwarf fleabane, and henbit.

 

Postemergence herbicides are applied following weed emergence when they are young and actively growing. Most are foliar absorbed, so they must remain on weed foliage for 24 to 48 hours following application. Postemergence broadleaf herbicides kill target weeds without injuring turfgrasses when applied at recommended rates. Examples include, 2,4-D, dicamba, MCPP and various other herbicides. Normally, two to three spray applications, spaced 10 to 14 days apart, are required for effective weed control. Broadleaf herbicides can damage desirable landscape plants if misapplied; be sure to read and follow label directions to protect landscape plants.

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Preventing Winterkill in Warm-Season Grasses: Managing Winter Desiccation

Mingying Xiang, Assistant Professor, Turfgrass

 

As we move into winter, the ongoing drought in our region significantly threatens the winter survivability of warm-season turfgrass such as bermudagrass and zoysiagrass. While many homeowners and turf managers are aware of the risks associated with freezing temperatures, desiccation—the excessive drying out of plants—presents an equally critical concern. Additionally, a warm fall, such as this year’s, can delay the winter acclimation process for warm-season grasses, making them more vulnerable to winterkill.

 

Key Tips for Homeowners and Turf Managers

1. Understand Desiccation and Its Risks: Desiccation occurs when turfgrass loses more water than it can absorb, leading to dryness and increased vulnerability to damage, especially during cold, windy winter months. This dehydration weakens the grass, making it more prone to winterkill. With current drought conditions, many turfgrasses are already under stress. If moisture levels remain low throughout winter, this stress can intensify, potentially resulting in significant turf loss come spring.
2. Irrigate Before and During Dormancy: It is essential to ensure that turfgrass has adequate moisture before entering dormancy and to maintain moisture levels throughout the winter to prevent desiccation. Fall irrigation, combined with a less frequent winter watering schedule, can help maintain optimal soil moisture levels during the colder months and reduce the risk of desiccation.

Takeaway Message: As drought conditions persist, preventing desiccation is crucial to protecting warm-season turfgrass from winterkill. By ensuring adequate irrigation before dormancy and maintaining proper soil moisture throughout winter, homeowners and turf managers can reduce the risk of turf loss during the colder months.

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Drought Conditions Causing Issues for Pecan Growers

Becky Carroll, Senior Extension Specialist

 

Dry conditions are creating extremely dusty conditions for pecan harvesters. Clouds of dust make it easy to see where pecan equipment is running. The dry weather has allowed harvesters to work from morning to night for most of the month. With low dew points and little moisture on the ground, harvesters don’t have to wait for the grass to dry in the morning. While this is beneficial for getting the harvest in for the holiday markets, growers are desperate for rainfall.

 

Extreme drought has affected many pecan-growing counties, with severe and moderate drought conditions prevailing in most areas. Some Mesonet stations report over 74 consecutive days with less than 0.25 inches of rainfall.

 

 

 

These dry conditions may lead to additional harvest issues for growers. A lack of water can increase stick tights or shucks that do not open properly or at all. Shuck opening is controlled by a gas hormone from the kernel that triggers enzymes to weaken cell connections at the shuck sutures. Additionally, the shuck absorbs water after potassium is quickly transported from the leaves, which also contributes to shuck opening. A shortage of water or potassium can disrupt this process, potentially weakening the trees and causing early leaf loss.

 

During drought conditions or when trees are overcropped, nuts may abort to allow the tree to focus on filling a partial crop. Without sufficient water, pecans may halt development, and shucks will remain tight. Damage to the kernel during development—whether from insect feeding or lack of water—can lead to nut abortion and stick tights. Nuts may either drop or remain on the tree. Overcropped trees and poor pollination can also complicate shuck opening.

 

Pecans that lack adequate water during kernel fill may develop wafery, lightweight kernels with air pockets. Kernel fill typically begins in early to mid-August, depending on the cultivar.

 

Summer months with limited moisture will result in smaller-than-normal pecans. Water is especially crucial in June, July, and August before shell hardening. Once the shells begin to harden, the nuts will not increase in size. We normally recommend supplementing with irrigation to achieve the largest pecan sizes. Growers with limited water in the fall during kernel fill may find that smaller nuts are beneficial, as larger pecans require more water for proper filling. Those without irrigation may consider planting cultivars that produce smaller nuts to ensure well-filled kernels each year.

 

Pecan trees require about 54 inches of water per year. In most areas of the state, irrigation is necessary. For those planting a new orchard, irrigation is critical for supplementing water during key times for nut development. Providing two inches of water per week during the sizing stage and an additional two inches per week during kernel fill is optimal for producing the highest quality pecans.

 

 

Dry conditions may weaken the trees' root systems, putting them at risk for winter injury and complications in the following season. Forecasted rainfall later this week may help with later ripening cultivars to open shucks but will be too late for quality issues. 

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Fall Cleanup

David Hillock

 

As plants in the landscape go dormant or are killed off by colder temperatures, it is a good time to do some fall cleaning in the landscape.

 

Leaves falling from trees are a good source of mulch and compost. If there are groundcovers or turfgrasses growing in the area, then it is best to remove the leaves and compost them or use them as mulch. Many beneficial insects and pollinators survive in leaf litter through the winter months. When removing leaves from turf areas, consider raking them into landscape beds instead of composting them. In wooded areas where there is little understory growth it is best to leave the leaves to decay naturally, which will also provide habitat for beneficial insects.

 

Many beneficial insects as well as pollinators also survive in stems of perennials. Don’t cut perennials back until late winter/early spring just before new growth, and even then, do not chop them up but let them fall to the ground or throw them into a corner of the landscape to allow any insects to emerge unharmed.

 

Other types of landscape debris like prunings from trees and shrubs or soft tissue perennials (i.e., canna, hosta) can be chipped or ground up to be used in compost piles or as mulch. However, if plants have been plagued with diseases and insects it may be best to remove them completely from the garden by burning them (if allowed in your community) or sending them off to collection facilities. Debris infected with diseases or harmful insects remaining in the landscape will only become a source of infection next year.

 

Sanitation is an important step in reducing outbreaks of pest problems. A good example is the twigs that frequently fall from trees like pecans. It is very possible they are infected with the larvae of a twig girdler. Larvae overwinter in the dead twigs, eventually pupating in the twig and emerging as an adult next summer. Another good example is the numerous foliar diseases that also overwinter on dead leaves and debris only to spread to new growth the following spring. Removing these organisms from your garden will reduce the chances of them recurring the following year.

 

Finding that balance of leaving some material for the good guys and removing debris infected with pests can be challenging. Use your best judgement.

 

Another practice during the fall and winter months that helps keep pests at bay is occasionally tilling fallow ground. Flower or vegetable beds that remain empty during the winter months can be tilled just before freezing temperatures. Hibernating insects are brought to the surface where they will be exposed to and killed by the cold temperatures.

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Winter Protection of Broadleaf Evergreens

David Hillock

 

A group of plants that often experience winter damage are the broadleaf evergreens such as hollies and boxwood. Water loss can cause severe damage to broadleaf evergreens during winter when high winds or temporary warm weather causes a plant to give off an unusually high amount of moisture.

 

When this water loss occurs at times when there is little or no winter precipitation and the soil is dry, or the ground is frozen, roots cannot take up moisture to replace lost water. The result is a browning or burning of the foliage. When soils are dry, they can also get colder which could result in root damage too.

 

Various management practices may help to prevent winter damage. Make sure the plants enter the dormant season in a healthy and vigorous condition with adequate soil moisture. Check to see that the center of the plant is free of dead leaves and other debris. And be sure to continue watering during the dry winter months. Monitor weather conditions and water during extended dry periods or about one to two times per month. Water only when air temperatures are well above 40 degrees F. Apply water at midday so it will have time to soak in before possible freezing at night. Mulch the plant with wood chips to reduce water loss from the soil. Mulch also protects the plant by preventing rapid temperature changes at the soil surface.

 

Boxwoods seem to be more susceptible to winter damage. Boxwoods placed in sites exposed to winter winds tend to experience more damage. Provide wind protection for plants in exposed situations by creating a simple wind break. Use snow fences or stretch burlap between stakes or over a lattice frame set next to the boxwood. Or you can stick pine boughs in the ground around plants to form a wind break. When planting boxwoods, it is best to avoid exposed, windy sites.

 

Large boxwoods and other evergreens prone to ice damage may be protected by wrapping the outer branches with strong nylon cord. Tie the cord securely to a low branch, pressing the boughs upwards and inward; wrap cord in an upward spiral around the bush, having cords 8 to 10 inches apart. Have cord tight enough to prevent breakage from excess weight of snow or ice, but not tight enough to exclude air circulation around the plant.

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Controlling Deer Damage

David Hillock

 

Oklahoma’s white-tailed deer (Odocoileus virgin­ianus) population has increased from 40,000 to more than 250,000 since the 1960s. As the deer population expanded, deer moved into peripheral suburban areas. Increasingly, homeowners at the rural/urban interface must deal with damage to ornamental and garden plants. As deer begin moving into an area, homeowners initially enjoy seeing them and may actu­ally encourage deer to come into their yard by feeding them. Rural subdivisions may ban hunting or place restrictions on firearm use to protect their deer or for safety reasons. Homeowner attitudes begin changing after deer numbers increase to the extent that shrubbery shows heavy browsing and gardens become difficult to grow because of continued depredation. In addition to browsing, damage may occur in the fall when bucks begin rubbing antlers on small trees or young nursery stock.

 

Commonly Used Control Methods

The problem of damage control is not an easy one to solve. Trapping and moving excess deer is often suggested by homeowners as a humane alternative to hunting with guns or even limited hunting with archery tackle. However, the cost to move enough deer to lower damage to tolerable levels is prohibitive. It should be recognized that most areas of Oklahoma are well populated with deer. Any deer moved to another area will only shorten food supplies for both resident and transplanted animals. Nature will then control the excess through starvation or decreased reproductive success because of chronic malnutrition. At best, trapping and relocating problem deer is only a short-term solution. 

 

Deer damage control methods fit into six catego­ries:

1. exclusion—by electric fence or eight-foot high, deer-proof fence,
2. scare or frightening tactics—with tethered dogs, gas exploders, fireworks or discharging firearms,
3. habitat modification,
4. population reduction through sport hunting,
5. repellents—area repellents repel by smell and contact repellents repel by taste, 
6. alternative plantings. 

 

Control methods other than an 8-foot high, deer-proof fence or an electric fence reduce damage by 50 to 75 percent at best, and often much less. A deer-proof fence does not fit well with most landscaping plans and can be expensive if large areas are to be protected. For small gardens, a deer-proof fence can be cost effective. For best results they should be constructed before serious damage occurs.

 

Scare tactics work for only short periods of time but may be useful by providing enough protection to allow the crop to be harvested. Habitat modification is expensive and may attract deer if misapplied. A professional wildlife biologist should be consulted if this is the desired course of action. Population reduction by sport hunting is the most cost effective, long-term solution and should be seriously considered if damage is widespread. 

 

Repellents which provide an unpleasant taste or odor can be used, but damage will not be entirely eliminated. Effectiveness will vary with deer density, season, and availability of alternate foods. To be effective, repellents must be applied before deer begin actively browsing in the affected area. Area repellents are generally less effective than contact repellents. Research results on the relative effectiveness of area and contact repellents from several sources can be found in OSU fact sheet HLA-6427 Ornamental and Garden Plants: Controlling Deer Damage. Bear in mind that repellents will not completely eliminate damage and that a given method’s effectiveness will change seasonally, based on what natural foods are available to deer. Many repellents do not weather well and will need to be reapplied after a rain.

 

To see a list of plant material that may or may not be affected by deer or for more information on control see fact sheet HLA-6427 Ornamental and Garden Plants: Controlling Deer Damage.

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Controlling Insects in and Around the Home

David Hillock

 

The first important step in the process of insect control is to identify the insect that is present so that the proper control procedure will be used. OSU county extension educators and pesticide dealers can help identify the pest for the homeowner, or the pest may be sent to the OSU Entomology & Plant Pathology Department for identification.

 

Sanitation and good housekeeping are possibly the most important aspects in controlling or preventing pests, but even well-kept homes sometimes become infested. The homeowner can usually control light infestations of pests in the house by carefully following directions on the pesticide container and by doing a thorough job of applica­tion.

 

Certain pests found outside may be eliminated before they enter the home. (For information on control of pests outdoors, refer to OSU Extension Fact Sheet EPP-7306 - Ornamental & Lawn Pest Control (for Homeowners). However, some insects live entirely within the home, where they must be controlled by applying spray, dust, bait or aerosol pesticides to areas where they are most frequently found. If the infestation is severe and widespread, it is advisable to employ the services of a pest control firm, which has pesticides and application equipment not generally available to homeowners.

 

For more information on pesticides and their use in and around the home see EPP-7312 Household Pest Control.

 

Safety Tips

•  Read and follow all directions on the container label.
• Avoid repeated or prolonged contact of insecticides with the skin and prolonged inhalation of spray mist.
• Do not spray oil solutions near an open flame (pilot lights).
• Do not risk contaminating food by treating near food, dishes or cooking and eating utensils.
• Dispose of empty pesticide containers, and do not punc­ture or incinerate aerosol or pressurized spray cans.
• Store insecticides in the labeled original containers, in a dry place where they cannot contaminate food items and where children and pets do not have access to them.
• After using pesticides, always wash your hands and face and any other exposed body areas.
• For further information on handling, mixing, and ap­plying pesticides, consult your area or state extension entomologists, visit your local county extension educator, and/or refer to OSU Extension Fact Sheet EPP-7540 for information on safe use of pesticides.

 

Prevention and Control Hints

Before applying insecticides for pest control, the home­owner can help ensure better control by doing the following: 

1. Clean out areas that make good homes for the pests.
2. Clean up areas that collect grease, food scraps or other spillage which might provide a food source.
3. Eliminate excessive storage boxes from the attic and garage and clean up foliage or other hiding places from around the outside foundation of the house.
4. Seal up cracks and crevices around the home to keep insects looking for a place to hibernate over the winter from entering the home.
5. If grain or flour pests are present, locate the infested material. Go through all cereal boxes, flour, beans, dry pet food, and spice containers until the infestation source is located. Dispose of the infested material, then a light application of pesticide.
6. Carefully check newly purchased dried foods for insect infestations, and store foods in tightly sealed glass, plastic or metal containers rather than in sacks, bags, or boxes.

NOTE on ultrasonic electronic or sound control devices: To date, these devices have not been proven to be effec­tive or practical.

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Protecting Young Trees

David Hillock

 

Trunks of some newly planted trees, especially those with green trunks or smooth, thin bark, require protection from direct sunlight during all seasons. They are especially susceptible to sunscald (blistering and cracking of the bark) during winter months when leaves are absent. Protect the trunk with a commercial tree wrap such as a polyurethane spiral wrap or material such as burlap. The wrap should be applied in the fall but should be removed prior to trunk expansion each spring.

 

The most reported damage from trunk protective wraps is trunk girdling or constriction because the wrap was too tight or left on too long. Generally, a tree will only need to be wrapped the first season or two after planting.

 

Tie the wrap firmly, but not tightly. Polyurethane wraps expand without binding the trunk. Start at the ground and wrap up to the first branch slightly overlapping as you go. Do not attach wraps with wire, nylon rope, plastic ties, or electrical tape.

 

Plants prone to winter desiccation, such as broadleaf evergreens, when planted in open windy areas may require additional protection. Temporary protective barriers such as sheets of burlap, lathe fencing, bales of hay etc. can be constructed to provide protection from the drying winds. Unfortunately, antidesiccants generally do not relieve plant stress in Oklahoma in winter or summer.

 

Protect young trees and shrubs from animal damage. Polyurethane wrap, wire mesh collars or rodent repellent paint can be used. Holly, honeylocust, elm, and fruit trees are particularly susceptible. Remember snow will change the height of the bite.

 

For more information on protecting landscape plants during the winter see OSU fact sheet HLA-6404 - Winter Protection for Landscape Plants.

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Dirt Artwork

Casey Hentges, Associate Extension Specialist

Bailey Singleton, Extension Assistant

 

When looking around the garden, it’s easy to see the beauty that grows from our soil. Oklahoma is known for its’ red dirt, but why is it red? What happens to iron when it is exposed to the elements of oxygen and rain? It rusts. Oklahoma soils are high in iron, and just like metal, our soils have that infamous color.  

 

As Oklahomans we know how diverse our state is and how variable the weather and rainfall can be from east to west and north to south. Not only does this influence the plants but it also influences the soils we have here. Among the 2,500 different kinds of soil across the state, port silt loam is the most common type of soil, which is found in 33 of our 77 counties. And in fact, is recognized as our state soil – did you even know that there is a state soil?

 

Just because the gardening season is winding down, doesn’t mean we can’t play in the dirt.  

 

To get started:

1. Collect several samples of soil that are well pulverized.  
2. Make sure the soil is broken down into a powder as much as possible, because it will be used as a pigment for the paint color.  The soil can be broken down by using a hammer and bucket or a mortar and pestle.  
3. Put some clear acrylic paint on a painter’s pallet, or some other material, add in some of the soil.
4. Add just a few drops of water to thin the mixture.  Of course, the amount of soil pigment and water added will influence the concentration of the color.  

 

In order to paint, paintbrushes and paper are needed. Watercolor paper will help absorb the water and pigment better.  

 

There is a wide range of colors that might be seen, from dark black and yellow, to red and many more.

 

Finally, depending on your artistic skills, you can either draw or trace something with a pencil first or just begin painting freehanded. The point of this activity is to have fun and try something new! It is another fun way to preserve one of the most important aspects of our garden – the soil.  

 

If you want to find more ways to get your kids outside and in the dirt, check out the Oklahoma Ag in the Classroom website. 

• Soil Science
• Oklahoma State Soil
• Using Soil to Make Art
• Soil Planting