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GARDEN TIPS FOR JULY!

 David Hillock

Vegetable Garden

  • Make fall vegetable garden plantings in late July. Fact Sheet HLA-6009 gives planting recommendations.

Lawn

  • Brown patch disease of cool-season grasses can be a problem. (HLA-6420)
  • Meet water requirements of turfgrasses. (HLA-6420)
  • Fertilization of warm-season grasses can continue if water is present for growth. (HLA-6420)
  • Vegetative establishment of warm-season grasses should be completed by the end of July to ensure the least risk of winter kill. (HLA-6419)
  • Mowing heights for cool-season turfgrasses should be at 3 inches during hot, dry summer months. Gradually raise mowing height of bermudagrass lawns from 1½ to 2 inches.
  • Sharpen or replace mower blades as needed. Shredded leaf blades are an invitation to disease and allow more stress on the grass.

Tree and Shrub

  • Control bermudagrass around trees and shrubs with products containing sethoxydim, fusillade or glyphosate herbicides. Follow directions closely to avoid harming desirable plants.

Fruits

  • Continue insect combat and control in the orchard, garden, and landscape. (EPP-7306, EPP‑7313, EPP-7319)
  • Check pesticide labels for “stop” spraying recommendations prior to harvest.
  • Harvest fruit from the orchard early in the morning and refrigerate as soon as possible.

Flowers

  • Divide and replant crowded Hybrid iris (Bearded Iris) after flowering until August.

General Landscape

  • Water plants deeply and early in the morning. Most plants need approximately 1 to 2½ inches of water per week.
  • Providing birdbaths, shelter and food will help turn your landscape into a backyard wildlife habitat.
  • Insect identification is important so you don’t get rid of the “Good Guys.” (EPP-7307)
  • The hotter and drier it gets, the larger the spider mite populations!
  • Expect some leaf fall, a normal reaction to drought. Water young plantings well.

Watering the Yard and Garden Efficiently

David Hillock

During the summer, watering the landscape and garden can be the primary focus of our activities. Irrigation systems, whether a simple hose-end sprinkler or an elaborate in-ground system, help us accomplish this great task with a little more ease. Obviously some systems require a little more attention and effort than others. However, all should be closely monitored and managed so that they are working efficiently and providing adequate coverage for the plants’ needs.

A minimum of one inch of water per week is usually required to maintain optimum growth of most plants. However, that will vary depending on the types of plants grown, the soil type, and weather conditions. During the hottest and driest part of the summer, two or more inches per week may be necessary. But, how much water does your sprinkler(s) put out?

One way to find out how much water your system is discharging is to catch the water. Use straight-sided canisters such as tuna cans and place them randomly under the sprinkler pattern. About six cans work well. Turn the sprinkler(s) on and let them run for about 15 minutes. Turn off the water and measure the depth of water caught in each can using a simple ruler. Average all the measurements together and this will tell you how much the system is discharging and how long to run the sprinkler system. For example, you wish to place one inch of water when you irrigate. The average amount of water that was measured when running the system for 15 minutes was .25 inches. So, you will need to run your system for one hour in order to irrigate one inch.

Some plants require constantly moist soils to maintain optimum growth and performance while others are quite drought tolerant and might even prefer drier soils. One way to make sure all the plants in the landscape are getting what they need is to group plants together based on their watering needs. Be careful not to plant together two plants that have completely different water needs or one of them will eventually suffer and die.

Brown Patch Disease of Cool-Season Grasses

David Hillock

Brown patch is a disease that commonly shows up on cool-season turfgrasses, especially tall fescue, but can occasionally appear on hybrid bermudagrass and zoysiagrass. Brown patch disease appears as brown patches up to three feet in diameter. Leaves first take on a dark color, then wilt and turn brown. 

Brown patch usually occurs in hot, humid weather when night temperatures are above 60°F and foliage remains wet for prolonged periods. Poor soil drainage, lack of air movement, cloudy weather, heavy dew, overwatering and watering in late afternoon favor prolonged leaf wetness and increased disease severity. The application of high rates of nitrogen and or deficiencies of phosphorus and potassium, especially when weather conditions are favorable for brown patch, can increase disease severity. Excessive thatch, mowing when wet and leaf fraying by dull mower blades can also enhance the severity of brown patch.

Control starts with good management practices. Though there are varieties of turf-type tall fescue that are considered resistant to brown patch, even resistant varieties succumb when growing conditions are less than ideal for growth of strong plants (as described above) and environmental conditions are highly favorable for disease development. 

When environmental conditions favor disease, avoid application of excessive rates of nitrogen. Fertilizer should be applied judiciously, and adequate amounts of phosphorus and potassium are essential to ensure the highest possible levels of plant resistance. In general, cool-season turfgrasses should not receive more than one pound of actual nitrogen per 1,000 square feet at any one time. Use very low rates or avoid applying nitrogen in late spring or summer to cool-season turfgrasses. In a typical home lawn situation, the last application of fertilizer in the spring should be applied no later than early May. Ensure adequate amounts of phosphorus and potassium by applying these nutrients based on soil test results.

Reduce prolonged leaf wetness by watering infrequently to a depth of 6 to 8 inches and at a time when the foliage is likely to dry quickly. Avoid watering in late afternoon and evening, and allow for better air movement by removing unwanted vegetation and selectively pruning trees and shrubs. Removal of morning dew reduces prolonged leaf wetness and exudates that favor disease development. This can be accomplished by dragging a hose across the turfgrass or by running the irrigation system for a short time period. Good surface and soil drainage must be present to reduce disease incidence.

Make sure mower blades are sharp to reduce the amount of wounded turfgrass in which the fungus can enter the plant. Collect and promptly dispose of clippings on infected areas or when conditions favor disease development. Avoid mowing turfgrass when wet, and do not mow too low so that the turfgrass will be better able to resist the disease.

Applications of effective fungicides, when the first disease symptoms appear, will give good control of brown patch on highly maintained turfgrass. A preventative fungicide program should be considered in areas where the above conditions are difficult to control or change and when conditions are favorable for disease development.

For more information on managing cool-season grasses see leaflet L-442 Cool-Season Lawn Management Calendar and fact sheet HLA-6420 Lawn Management in Oklahoma

Dividing and Replanting Iris

David Hillock

Irises are relatively carefree, easy to grow and long lived perennials; however, they should be divided every three to four years when they become crowded. Crowded iris will begin to decline in growth and will have fewer and smaller flowers.

Divide the rhizomes (underground stems) after the plants have flowered; July through August is the best time to do this in Oklahoma. Throw away any segments that are diseased, riddled with insects, or small and weak. Separate healthy rhizomes into segments with one fan of leaves and several roots. Cut the leaves back to six inches. When planting the new plant, spread the roots out in the soil and position the top of the rhizome at the soil surface. If planted too deep they will not flower as well and are more susceptible to disease and insect attack.

Diagnosing Problems in the Landscape and Garden

David Hillock

Throughout the growing season a number of problems can arise in the landscape and garden. The County Extension Offices throughout the state as well as your local garden professionals are a good source in helping diagnose the problem. The County Educators and garden professionals are trained to look for and ask certain questions to help narrow in on the problem. Knowing some of the things they will be looking for will help you possibly diagnose the problem yourself or be better prepared with the information they will need to solve the dilemma. Here are some of those areas to consider.

  1. Keep an open mind. Do not jump to conclusions.
  2. Avoid assigning “Guilt by Association.” The insect, animal, or disease observed may not be the actual cause of the problem or symptom.
  3. Take a thorough history: weather extremes, site alterations, fertilizer and pesticide use, cultural practices, etc. Once mature trees (especially pines and oaks) begin to decline, there is often no way to reverse the process.
  4. The symptom may indicate a problem in a different part of the plant. Example, brown leaves may be the result of a root problem or trunk or stem damage.
  5. Know what the healthy plant should look like.
  6. At least one half of all observed landscape problems are not caused by insects or diseases. Try to eliminate other causes first.
  7. A particular problem may be caused by several factors.
  8. There is a great variation in the expected life-span of landscape plants. All plants go through periods of growth, maturity and decline. Plants grown in urban locations generally have shorter lives.
  9. Many pests and diseases are plant specific. Symptoms affecting more than one plant species may indicate cultural and environmental problems.

There are many other areas to consider and questions that may need to be asked. Be prepared to answer questions to the best of your ability. Remember, we can never ask enough questions. The more thorough you are the better the diagnosis will be!

New Invasive Blackberry Pest for Oklahoma – Broad Mites

Becky Carroll

Please ask your blackberry growers if they’ve had symptoms like the following pictures.  

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Starts as leaf cupping on primocanes.

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Then see delayed bud break or weak or dead floricanes.

This damage is caused by Broad Mites. They were first confirmed in Oklahoma blackberries in May of this year. They had been seen in Arkansas on primocane fruiting berries since 2006 and now about 10 other states have reported damage. Since this is the first sighting on blackberry in Oklahoma, we need to determine how widespread the pest is in the state. If you have growers with similar damage, please let me know so we can get samples to the diagnostic lab for identification. More information is available in the following link to a Pest e-Alert from Dr. Eric Rebek on Broad Mites on Blackberries that was published recently.  http://entoplp.okstate.edu/pddl/2017/PA16-28.pdf.

Upcoming Events

Cimarron Valley Research Station Horticulture Field Day Part II – August 1

  • Want to know what is going on at the Cimarron Valley Research Station with horticultural crops? Make plans to attend the scheduled Horticulture Field Day on August 1, 2017 from 1 to 4 p.m. This tour and field day will be similar to the May field day that was held but a new batch of crops will be toured and discussed. Please meet at the North entrance on 104th Street just north of Perkins. There is no charge for event. Participants will get to tour and learn about pumpkins, cow peas, grapes, pecan crop load thinning and other horticultural crops.

Current Challenges in Floriculture – Shackelford Lecture Series, August 3

  • The Current Challenges in Floriculture Conference will be held on Thursday, August 3, 2017 at the Wes Watkins Center in Stillwater, Oklahoma. A variety of topics, taught by both academics and industry leaders, will be highlighted at this year’s conference.  Although an overview of floriculture issues and challenges will be discussed, water quality and quantity will be emphasized by one of the keynote speakers, Dr. Genhua Niu, Texas A&M, El Paso.  The conference is designed to interest both the commercial grower/retailer as well as gardening enthusiasts.  Pesticide applicators may also find this event useful as ODAFF CEUs in categories 3 and 10 will be offered. Registration is $30 per person and includes lunch. For more information, please visit www.hortla.okstate.edu.

Fall Pecan Field Day Set for September 22

Knight Creek Farms near Sapulpa will host an upcoming field day for interested pecan growers. This free event will showcase topics like early pecan harvest and drying operations; row harvesting; new planting and irrigation options; wildlife control options; and marketing. 

The field day is scheduled to begin at 2 p.m. on Friday, September 22 and dinner will begin at 6 p.m. sponsored by Grissoms John Deere. More information and directions will be available soon for this event presented by Oklahoma State University, Noble Research Institute and Oklahoma Pecan Grower’s Association.

Viticulture & Enology Workshop Scheduled October 24

A special workshop will be held at Waddell’s Vineyard & Winery near Ada on October 24. Registration for the event will begin at 8:30 a.m. and the presentations will commence at 9 a.m. Featured speakers from Texas AgriLife Extension program include Dr. Justin Scheiner and Michael Cook.

Dr. Scheiner will be making a return appearance to share expertise on many applicable topics for our Oklahoma growers. He was a favorite presenter at a 2014 advanced training workshop. Michael Cook is located out of Denton, Texas and has been spending some quality time in some of our Oklahoma vineyards lately. He has provided consultations to vineyards that had requested site visits through an Oklahoma Grape Industries Council grant. The OGIC grant as well as the grant for this workshop was made possible through the ODAFF Viticulture & Enology Fund.

Some possible topics for the day’s workshop include Grape Cultivar Selection, Fruit & Foliar Diseases, Understanding Vineyard Fungicides, and Grapevine Nutrition. Many of the topics will address challenges that vineyards are encountering as observed by Michael Cook on his site visits. This will be an excellent learning opportunity and will benefit all grape growers. An agenda will be available soon with more details on how to register for this free workshop. Lunch will be catered so an accurate count of those planning to attend will be helpful.

SAVE THE DATE – March 8, 2018 for a Horticulture “Spray Day”

A new horticultural event is in the planning stage that will be focusing on spraying, including fungicide, insecticide, and herbicides. This event will be held at the Cimarron Valley Research Station and open to anyone interested. Emphasis will be on equipment demonstrations for different crops and different sizes of operations; question and answer times; sessions on calibration, worker protection standards, pesticide certification requirements and pest management.  We hope to have vendors with different types of equipment and chemical representatives in attendance. Sponsored by Oklahoma State University Horticulture & Landscape Architecture Department, Oklahoma Field Research Service Unit, Noble Research Institute, Oklahoma Pecan Growers, Oklahoma Grape Industries Council, and Oklahoma Fruit & Vegetable Growers.

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