Best Lawns News. Spring 2014 Edition Virginia Cooperative Extension Prince William Unit. Featured in This Issue

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1 Best Lawns News Spring 2014 Edition Virginia Cooperative Extension Prince William Unit Featured in This Issue Better Know A Weed: Johnson Grass? 2 Cooperative Extension Turns Summer Watering Considerations for Turf 6 All content was written by Thomas Bolles, except where noted, and is based on university research at Virginia Tech, Virginia State and other partner universities in the Land Grant system. Staff contact information Paige Thacker, Extension Agent, Horticulture Phone: pthacker@pwcgov.org Nancy Berlin, Natural Resource Specialist/Master Gardener Coordinator Phone: nberlin@pwcgov.org Thomas Bolles, Environmental Education Specialist/BEST Lawns Coordinator Phone: tbolles@pwcgov.org Jennifer Graham, Administrative Assistant Phone: jgraham@pwcgov.org VIRGINIA COOPERATIVE EXTENSION 8033 Ashton Avenue, Suite 105 Manassas, VA Phone: Fax: Disclaimer Commercial products are named in this publication for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.

2 Johnson Grass In Virginia, Johnson grass (Sorghum halepense) is considered a noxious, invasive weed. Closely related to grain sorghum, Johnson grass is a warm season perennial that does well in hot dry conditions. Johnson grass is often found in corn fields, pastures and hay fields. It s also commonly found on the edges of fields, along roadsides, in ditches, and in disturbed soils. Johnson grass is uncommon in turf, but it s seeds are easily carried on the wind and can invade landscapes. Johnson grass can grow quite large over 6 feet! It spreads by both seeds and rhizomes. It s rhizomes are problematic as Johnson grass can easily resprout from very small pieces of rhizome. This means pulling and hoeing are usually ineffective in fully eradicating a mature plant. Roots and Rhizomes Johngrass has leaves with a prominent midvein. Leaves are rolled in the shoot. Leaf blades tend to be relatively wide. Leaf blades often do not have hairs on top or bottom, but may have them at the base of the leaf blade. If you pull the leaf blade away from the stem, you may notice a 3-4 mm membranous ligule which is often toothed at the top. Johnson grass stems are round to somewhat flatten. The sheath (the basal part of the leaf between the crown and leaf blade) may be green to maroon especially near the base of the plant

3 Ligule Maroon Sheath Midvein Johnson grass can be mistaken for a number of other grasses, including grain sorghum/shattercane (Sorghum bicolor), barnyardgrass (Echinochloa crus-galli) and fall panicum (Panicum dichotomiflorum) prior to seedhead formation. However, Johnson grass has a membranous ligule unlike that of fall panicum or barnyardgrass. Johnson grass seedlings do not have hairs on the lower leaf surface like those of fall panicum. Johnson grass seedlings and mature plants also resemble sorghum/shattercane (Sorghum bicolor), but sorghum/shattercane does not have rhizomes like Johnson grass. Young Johnson Grass

4 Johnson Grass Inflorescence (Flowers) As a homeowner, you want to be able to recognize this weed on your property. A few years ago, a neighbor of mine found a volunteer grass in her back yard. She thought it was an ornamental so she fertilized and mulched around it. By the time I saw it over the fence, it was almost 6 tall and about to flower. By then, the plant had formed thick rhizomes (1/2 inch diameter or more) and had begun to aggressively spread into her lawn. Young Johnson Grass with Rhizome Like so many weeds, early detection makes control of Johnson grass easier. Young plants can be pulled or dug up, if done carefully. Notice the picture above. This plant is fairly young, but it already has a rhizome that extends a good distance from the shoots. Pulling/digging is more likely to be effective in moist soil. Repeated close mowing of young plants can be an effective control. Spot treatments with non-selective herbicide, like glyphosate, can be effective but repeated applications may be necessary for well-established plants. Glyphosate can harm other plants, including turf, so care is necessary when treating Johnson grass. Do not apply on windy days. Glyphosate needs to be applied when the weed is actively growing. It is also important that glyphosate is not applied when air temperatures exceed label recommendations. Sources: Virginia Tech, Ohio State and University of Missouri

5 Thinking about growing vegetables this year? Check out Master Gardener Paul Gibson s Sustainable Vegetable Blog at: Cooperative Extension Turns 100 Throughout much of American history, higher education was beyond the means of most Americans. Most colleges were private and very expensive. In an effort to make higher education more available to more Americans, Vermont Representative Justin Smith Morrill introduced legislation to use the sale of federal lands in the West to create public universities in every state. The Morrill Act of 1860 established a system of state land grant universities throughout the United States. In the Commonwealth, there are two schools in this system: Virginia Tech and Virginia State University. Even with the establishment of the land grant colleges, higher education remained largely beyond most Americans. Some experimentation with delivering the practical applications of university research had been tried the states. Congress, however, decided to address the issue of how to organize a national system to bring practical research to the people. After several attempts to develop a unified system, the Smith-Lever Act was passed in Originally intended to educate the public in matters of agriculture, natural resources, home economics and rural energy, Extension today meets a wide range needs. Modern extension education programs include agriculture, youth leadership and development, parenting, personal finance, nutrition and economic development. The Prince William Unit of Virginia Cooperative Extension serves Prince William County, the city of Manassas and the city of Manassas Park. It is the largest Extension office in the state. Leveraging the efforts volunteers, the Prince William Unit touches the lives of thousands of individuals annually. This year, May 8 th has been declared Virginia Cooperative Extension Day to celebrate the 100 th anniversary of the passage of the Smith-Lever Act. Join us in celebrating 100 years of bringing practical knowledge to the Commonwealth. April 26-May 5 is Virginia Historical Gardens Week Consider visiting one of the many historical gardens in Northern Virginia and across the Commonwealth.

6 Summer Watering To water, or not to water is a question many people have as the weather gets warmer and rain becomes less frequent. This is a management decision many homeowners make without fully understanding the pros and cons of embarking on a summer irrigation plan. Cool Season Lawns Cool season grasses need 1 inch of water per week when actively growing. The typical cool season turf is most actively growing in spring and fall, with some growth occurring in the winter depending on light and temperature. In a natural setting, cool season grasses go dormant in the summer. They manage the stress of high temperatures and little moisture by shutting down until the weather is more favorable. In a normal year, a cool season lawn that is not irrigated over the summer will turn brown in the summer, but recover in the fall with minimal damage. The browning of the leaves during dormancy occurs as the plant pulls chlorophyll out of the leaves. During times of heat and drought, dormant grass can be injured. There are a number of management strategies that will help protect cool season grass during a drought. Keeping the turf mowed as high as possible can make a difference. Higher cut grass will have lower water loss through the leaves, keep the soil temperature several degrees cooler and help preserve soil moisture. Maintaining organic matter in the lawn through regular applications of compost* can also help. Organic matter in the soil acts like a sponge and can store water for use in times of need. This is especially useful in sandy soils, but can be effective in clay soils as well. Though there is some variance between specific varieties, most cool grasses, when dormant, can survive on ½ inch of water every 3 weeks during periods of extended hot, dry conditions. Many people prefer to keep their lawns green and vibrant over the summer. To keep a cool season lawn green and actively growing over the summer, it usually requires supplemental irrigation. To stay actively growing and out of dormancy, cool season grasses need 1 inch of water per week. Watering should be applied deeply and infrequently. That means watering 1 inch once a week (if your soil can absorb that much water at once) or watering ½ inch every 3-4 days. This encourages deep roots. Watering should always be done early in the morning to discourage fungal problems. There are, however, some things to consider before deciding to water your cool season turf this summer. Watering may keep your turf looking greener, but it will definitely stress your turf and increase the potential for damage from insects and disease. Watering over the summer can also get expensive. One inch of water covering 1,000 sf of turf requires nearly 625 gallons of water. Most single family homes have at least 5,000 sf. When you multiply that by 12+ weeks of summer and the cost can really add up if you re on municipal water. If you re on a well, summer watering becomes even harder to justify. If you choose to water cool season turf over the summer, stick to a regular schedule. Erratic watering or stopping and starting of a water regimen can seriously damage your turf. * Topdressing turf with compost is typically done in the fall or spring in conjunction with aerating.

7 Warm Season Lawns Warm season grasses actively grow over the summer. Watering may make the grass look lusher, but warm season grasses will do fine without supplemental watering. Bermuda grass can take a pretty severe summer in stride. Zoysia is a little more shallow-rooted and tends to wilt and discolor a little in extreme heat and drought. Like cool season grasses, zoysia and Bermuda grass will benefit from regular topdressing of compost to hold soil moisture. Mowing heights for warm season grasses should also be raised going into periods of drought. How Do I Know What 1 Inch of Water Is? You can get an idea of how long it takes to water your lawn an inch by setting out empty tuna cans randomly around the lawn and timing how long it takes to fill the cans. If you find you have water running off your lawn, it means your soil can t absorb 1 inch of water all at once. In that case, you should apply ½ inch of water every 3-4 days. When Should I Water? Watering your lawn during the humid summer can create a great environment for fungal diseases. Minimize this risk by only watering early in the morning: 6 am to 10 am. This will reduce evaporative losses, help wash off dew (which tends to be slightly sticky and will linger on the grass) and allow excess moisture on the leaves to dry. What Else Should I Think About? Have your sprinkler system regularly maintained. Clogs, leaks and sprinkler heads that have been knocked out of alignment can cause uneven water distribution and wasted water. Double check your timers to make sure they are set to deliver the amount of water where you want, when you want. Make sure to properly winterize your system to damage during cold weather. Install moisture sensors to ensure you don t water during or after a rain event. Understanding your turf s water needs and effectively managing to meet those needs will help you keep your turf survive the extremes of summer. May 5-11 is National Wildflower Week Experience the Beautiful of Native Plants

8 VCE Schedule of Classes Well Water Class Old Manassas Courthouse Results Meeting 7:00 pm, May 12 May 3 June 7 July 12 August 2 September 6 October 4 Master Gardener Saturdays in The Garden The Teaching Garden at St. Benedict Monastery 9:00 am to Noon Pollinator Friendly Gardening - Learn tips to attract and keep critical pollinators in your yard. Compost It! Learn the best way to set up, maintain and use compost in your landscape. Plus: Master Gardener plant sale and seasonal secrets for growing organic vegetables. Master Gardeners Favorite Plants Let Master Gardeners introduce you to some new and old favorites. Pruning - Clip It Right! June is the time for pruning azaleas, and other spring blooming shrubs! We will teach you what you need to know for abundant blooms next spring! Join us for a lecture & demonstration. Seasonal Solutions Seasonal secrets for growing organic vegetables. Plus: Emerald Ash Borer update Simple ways to use water wisely in your landscape. Learn how plants use water, plus tips on rain barrels, proper irrigation & best practices for utilizing water more effectively. The Fall Vegetable Garden Learn tips for planting the Fall vegetable garden & extending the seasons. The Frugal Gardener How to garden on a shoestring budget and get the most from your dollar. Seasonal Solutions Seasonal tips for the organic vegetable garden Weeds, Soil Health and Cover Crops Learn from VCE Staff & Master Gardener Volunteers how to improve your soil, identify weeds and use cover crops effectively. Tree identification Join ISA Certified Arborist, Rachel Habig, to learn the basics of tree identification. Storing Homegrown Produce Learn tips for storing your homegrown produce. Master Gardener Clinics at Local Garden Centers Lowes Gainesville, Lowes Woodbridge, Merrifield Gainesville and Southern States Manassas 10:00 am to 1:00 pm Saturdays: April 5 th, 12 th, & 26 th, May 3 rd & 17 th. Master Gardener Clinics at Manassas City and Dale City Farmers Markets Beginning April 12 th and running every other weekend through October All Classes are of these programs are free, except Well Water Sampling. Please register by calling or ing master_gardener@pwcgov.org