March 2012 / Volume 60        

In This Issue
March Lawn and Garden Tips
Home and Garden Show
Spring Plant Sale!
Oklahoma Proven Shrub for 2012
Weed Control: What's it all about?
Herbs in Your Windowsill
Update on the Drought
Ask A Master Gardener

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

51 degrees 


Rainfall total last 30 days:  

0.99 inches


4 Ways to Contact Us
Email us at:

See our website at: 

Call: 746-3701 from 9-4, M-F 
Visit us at 4116 E. 15th Street, Gate 6 at the Fairgrounds

Whether you call or bring samples of plants to the office, trained Master Gardeners will answer your gardening questions with science-based information.
Need More Information?

Click on any of the links below:


All about butterfly gardening in Tulsa County 

How to Take a Soil Test

How to collect a good sample of soil from your lawn or garden and get it tested at the OSU lab.
Understanding Your Soil Test Results
Once you have collected your soil test and gotten the results back, now what? Find out here. 
How to Plant a Tree in Oklahoma Soil
Show and tell.
Fescue Lawn Care
12-month maintenance calendar.
Bermuda Lawn Care
Ditto above.
Trees for Tulsa
A list of 50 recommended trees with descriptions.
Crape Myrtles
A list of over 60, by size and color.
Demonstration Garden
Visit our demonstration garden on 
15th Street, open 7 days a week.  
Oklahoma Proven Plants
State horticulturists, nurseries and growers pick favorite plants, shrubs and trees for use in the Oklahoma landscape. See the winners for this year and years past.
Current and historical source of rainfall, air temperatures, soil temps and much more. Click on Bixby station.  

Back Issues  

Past issues of our eNewsletters can be read and downloaded.

Become a Master Gardener

Classes start in September. Register for more information.

Oklahoma State University, in compliance with Title VI and VII of the Civil Rights Act of 1964, Executive Order 11246 as amended, Title IX of the Education Amendments of 1972, Americans with Disabilities Act of 1990, and other federal laws and regulations, does not discriminate on the basis of race, color, national origin, gender, age, religion, disability, or status as a veteran in any of its policies, practices or procedures. This includes but is not limited to admissions, employment, financial aid, and educational services.
March Lawn and Garden Tips


  • Average final freeze dates for our area are March 18 for a hard freeze and March 29 for a last light freeze. Dates outside the urban area may be up to two weeks later. 
  • Continue to follow the fruit tree spray schedule for each type of fruit tree in your garden.
  • Cultivate annual flower and vegetable planting beds to destroy winter weeds. Some weeds such as henbit, may over-winter spider mites.
  • Cool season vegetables like broccoli, cabbage, carrot, lettuce, onion, peas, spinach, turnips etc. should be planted by the middle of March. Start warm season veggie transplants indoors.  


  • Pre-emergent herbicides for crabgrass control may still be applied according to the labeled directions. A brand containing one of the chemicals dithiopyr, pendimethilin or prodiamine would be an excellent choice. Read and follow the label. They must be watered in to be effective and some will require a second application. See article below for specific information about warm and cool season grass care. 
  • Broadleaf weeds in cool season lawns may be easily controlled with post-emergent herbicides containing 2,4-D, such as Weed-B-Gon and Trimec.

  • March is the second-best time to seed cool season grasses (fall is the best time). Click here for seeding instructions. 

  • Fertilize cool season lawns such as tall fescue and bluegrass this month. Another application in May is optional, but do not fertilize these grasses in summer. For full Oklahoma lawn care information, click here
  • Begin mowing cool season grasses to 2 to 3-1/2 inches high. 


  • Plant evergreen shrubs, balled and burlapped and bare rooted trees and shrubs. Click here for a proper planting diagram. 
  • Fertilize roses with organic or slow-release balanced fertilizer at pruning time. Scratch into the soil; keep away from stems. Follow labeled directions; too much nitrogen will decrease blooming. Begin to spray roses for black spot if needed. Click here for more information on growing Roses in Oklahoma. 
  • Plant pansies, violas, primrose, snapdragon and other cold-tolerant annuals now. For more information on annuals in Oklahoma, including cold tolerant varieties, click here
  • Divide and replant overcrowded summer and fall blooming perennials. Cut back liriope and other ornamental grasses if you have not done so. For more information on perennials in Oklahoma, click here
  • Diplodia Pine Tip Blight fungus and Pine Tip Moth control is needed this month. See article below, or contact Master Gardeners for recommendations.

The More You Know...
The More You Grow

The 2012 Greater Tulsa Home & Garden Show is scheduled for March 8-11 in the QuikTrip Center at the Fairgrounds. Our goal is to provide valuable horticultural information and creative ideas for the home and backyard gardens. The More YOU Know, the more YOU can Grow your horticultural knowledge and successfully grow a beautiful yard full of turf, flowers, vegetables, and much, much more!  


There will be something for everyone's enjoyment, from the young to not so young, from nostalgic displays to new technology. Information about the show can be found on our newly created Web site. Come visit, and keep checking back as more information will be added between now and the show.

Tulsa County Master Gardeners
Spring Plant Sale! 
Have you turned in your order for the Spring Plant Sale yet? By shopping at our Spring Plant Sale, you make it possible for Tulsa County Master Gardeners to continue the many programs that are provided free in our community. We could not provide these services without your support.

How to Order: Order forms are available here in PDF and Excel format or from any Tulsa County Master Gardener office. 

Orders due: Wednesday, March 28th by 4pm. Order form and payment must be received (by mail or in person) at the Tulsa County Master Gardener office, 4116 East 15th St, Tulsa, OK 74112-6198.  

Sale Location: Tulsa County Fairgrounds, Central Park Hall

When: Plants must be picked up at Central Park Hall on Thursday, April 19th, between 9:00 am and 7:00 pm.  


Not sure what you want to order? You can click here for pictures and information for all plants on the order form.


Want to pay by credit card? You can do so by bringing your order form to the Master Gardeners' office at the address above during the following hours:

      March 19, 21, and 23 - 10:00 am to 1:00 pm

      March 26 and 27 - 10:00 am to 2:00 pm

      March 28 - 9:00 am to 4:00 pm


In addition to the many plants that you may pre-order, we will have an outstanding variety of plants available at the sale. We have been working with several growers to bring you an exciting selection of must-have plants for your garden. These will include hard-to-find native plants, Oklahoma Proven varieties, perennials, annuals, herbs and veggies. Shop early for the best selection...these plants go fast!


Thank you for your support of the Tulsa County Master Gardener Program!

 OK Proven Shrub for 2012  
The Oklahoma Proven shrub selection for the year is actually a collection of three cultivars from the juniper family. Junipers are widely diverse and come in upright, spreading or low ground cover habits. This collection contains all three forms. All of these cultivars are derived from native plants of North America, making them ideal for Oklahoma conditions. The cultivars selected are:

            Juniperis virginiana 'Taylor' - upright form

            Juniperis chinensis 'Saybrook Gold'- spreading form

            Horizontalis 'Monber' Icee Blue ® - ground cover


'Taylor' (above) is an evergreen conifer with semi-soft, blue-green foliage, growing 4 to 5 feet wide and 15 to 20 feet tall. The upright columnar habit of 'Taylor' gives it a rather formal appearance and makes it an excellent choice for a tight space. 'Taylor' makes a great flanking plant for an entrance or creates a dramatic vertical element for the landscape. Its appearance can help define features of a home such as corners, porches or an entry, or even establish a boundary. It has a denser upright form than many other conifers, making it a good choice for a privacy screen, windbreak or hedge. Once established, it needs only occasional watering.

'Saybrook Gold' has very bright gold foliage with gracefully arching branches. It holds its color all year round, taking on a more bronze tint in winter. It has a compact, spreading habit, reaching approximately 30 to 36 inches high and 6 feet wide. Because it responds well to trimming, 'Saybrook' can be easily maintained at a desired size. Use 'Saybrook Gold' for a striking addition to any landscape as a mid-level foreground plant, foundation planting or hedge. The extremely brilliant color is a knockout when mixed with any darker green foliage plants.

Icee Blue® 'Monber' is an easy care, mat-forming species with beautiful silver blue foliage. It exhibits the best silver blue of all junipers and turns plum purple in winter. It maintains a full dense crown, creating a solid cover in a short time. 'Monber' grows only 4 inches tall and can spread to 8 feet. It looks spectacular when scrambling over a retaining wall or around large boulders.


Junipers at a glance: In general, junipers are adaptable to a wide range of soils and can withstand hot, dry conditions once established. They may require extra watering for the first three years until well rooted.

Exposure: Full sun for best color, although they will tolerate partial shade

Soil: Moist, well drained

Hardiness: USDA Zones 4-9


For more Oklahoma Proven plants, click hereFor more extensive information about the selection, planting and care of new trees, read Fact sheet 6414 Planting Trees and Shrubs.    

LawnWeedControlWeed Control: What's it all about? 

Isn't it generally don't have green grass all year but you certainly can have green weeds all year, if your lawn is not treated properly. And, with so many products on the market these days, where do you start in figuring it all out?


Well, here's a simplified approach....herbicides for lawns come in two categories: pre-emergent and post-emergent. Pre-emergents herbicides are applied before the weed germinates (before you can see it), and post-emergents are applied after the weed is growing (once you see it). Both types of herbicides can be used on warm weather/summer weeds as well as cool weather/winter weeds. Choosing the right product and applying it at the right time are critical to successfully combating weeds in your lawn.


While both pre-emergents and post-emergents will work on crabgrass and other spring/summer weeds, pre-emergent weed control is much more effective. It is easier to prevent weeds as opposed to fighting weeds once they start to grow and spread. This also keeps the yard looking better overall. Timing of application is critical as a pre-emergent will not be effective if applied too early or too late. The best time to apply a first application for control of summer weeds (e.g. crabgrass, foxtail) is from mid February to mid March...keeping in mind that dates are subject to varying environmental conditions for each location and year. A second application may be needed some 60 days later for control of late germinating crabgrass and goosegrass, but only if specifically allowed by your product label. Also, remember that pre-emergents will not be effective unless they are watered into the lawn after application so that the soil surface is coated with a thin layer of herbicide. This is a common mistake made by many homeowners. And, as with any weed control product, ALWAYS read the label for specific directions!


Post-emergents, on the other hand, can be applied anytime weeds are actively growing. All post-emergent herbicides are termed either selective or non-selective. Selective herbicides control certain weeds without injury to desirable turfgrasses when applied according to label instructions (e.g. a combination of 2,4-D, dicamba, and MCPP), while non-selective postemergence herbicides kill or injure most green, actively growing plants (e.g. glyphosate as found in Roundup and many others). Post-emergents are generally foliar applied and absorbed, so they must remain on the leaf surface for 24 to 48 hours following application for adequate absorption. Post-emergents containing glyphosate may also be effective in eliminating cool season weeds in dormant Bermuda grass lawns, but should not be used on fescue or zoysia lawns at any time of year.


Here are a couple of very handy references, depending on the type of lawn you have: Bermuda Lawns and Fescue Lawns and a Lawn Management fact sheet. Not sure what weeds are growing in your lawn? Click here for an identification chart. Ultimately, the most effective preventative measure is to cultivate a healthy, thick lawn which prevents weed seed germination and crowds existing weeds.  

Herbs in Your Windowsill  

There is nothing more gratifying than seasoning a home cooked meal with home grown herbs. Even if you do not have the space for an outdoor herb garden, many herbs can be conveniently grown from your kitchen windowsill. A south-facing window is best, although any location that provides a warm, sunny condition will work. Plants can be started from seeds (see last month's newsletter for directions on starting seeds indoors) or purchase transplants from a local nursery. They can be grown in a narrow window box, a series of small terra cotta pots, or even vintage tea tins; any small container that has adequate drainage will suffice. Following are some of the more common culinary herbs, their care and usage:


Basil - Prefers a rich, moist, well-drained soil. Harvest the leaves while they are still young. Avoid chopping, as it causes them to bruise. Instead tear with your fingers and add at the last minute to chicken or sauces; or as a garnish for salads. Basil is also one of the primary ingredients in pesto. When the leaves are brushed, they release their oil giving the kitchen a wonderful fragrance.  


Rosemary - This herb likes warm, dry conditions evocative of its Mediterranean origins. Take care not to over water as this will kill the plant. To harvest, snip off the branches and separate the leaves. Combine with olive oil to use as a seasoning for roasted potatoes, or use to flavor lamb or poultry. Can also be used in potpourri.  


Thyme - Easy to grow indoors, thyme prefers a well drained soil. To harvest, snip off a stem and strip the leaves. Use to flavor a variety of dishes from poultry to soups, as well as sauces and vegetables. Can also be combined with softened butter for cooking or spreading on warm bread.  


Parsley - Prefers a moist soil. Harvest the outermost stems of the plant, finely chop and use as a garnish or for seasoning.

For more information, visit our Web site for more information on the cultivation of various herbs. Or click here for more information on growing herbs indoors.

Update on the Drought  

So, how do you like THIS weather? Love it or hate it, this winter has been markedly different compared with last year. Different, except for one key aspect...drought! Some autumn rains helped temporarily, but as we move into spring, we find the Tulsa area back into moderate drought conditions...and some areas not far to our northwest are in the extreme category. Most of northeast Oklahoma has received only about 50-75 percent of normal precipitation since October 1, 2011.


Seasonal outlooks for spring don't offer much help one way or the other, forecasting equal chances of above, near or below normal precipitation for March through May. The Climate Prediction Center's Drought Outlook does call for some improvement, mainly because we are about to transition into our wettest time of the year.


But, if you are one who doesn't like the cold and snow, take solace in knowing this has been the 7th warmest winter on record in Tulsa, and is well on track to be one of the least snowy winters we have seen in many years.

For more information about the current condition of the drought in Oklahoma, click here


PineProblemsQuestion: I recently planted a few small pine seedlings in my yard, and was wondering if pine trees are susceptible to any pest or disease problems?

Answer: Pine trees are an excellent way to provide winter interest to your landscape, and while not native to the immediate Tulsa area, many species are adaptable to our conditions. There are several potential problems with even the best-adapted species, however. The two most common issues for pines in early spring are the Pine Tip Moth and a disease known as Diplodia Tip Blight.

The Nantucket Pine Tip Moth overwinters as pupae in the damaged branch terminals of infested pine trees. Adults have a gray body with a wingspan of about ½ inch, and the forewings are covered with brick red or copper colored patches. The adults emerge in March and April and then mate, with females laying eggs on the needles within a day or two after emerging. The larva will hatch in 5 to 10 days in warm weather, (up to 30 days later in cool weather) and construct a small silken web in the axil formed by a needle and the stem. The larvae feed for a few days on the base of the needles and on the surface of the stem. Resin and frass accumulate on and around the web as they feed. Later, they migrate to the shoot tips, construct a new protective web, and tunnel into the stem or bud. Feeding continues inside the stem until larvae are fully grown (2-4 weeks), then pupation occurs within the cavities formed by the larvae.


The first visible sign of damage is the browning and dying of a few needles at the tips of the branches. As the larvae burrow into the stems, the branch tips die and turn brown. With additional feeding, this dead area may extend several inches down the twig. Although trees are seldom killed by its attacks, repeated infestations reduce the growth rate, deform the main stem, lower wood quality, and give the trees a bushy appearance. The Most severe damage occurs on susceptible species of pines that are less than 15 feet tall and growing in open areas.


Maintenance of high tree vigor by fertilization and irrigation is an effective method of reducing damage. This also promotes rapid growth through the first six to eight years, when the tree is most susceptible to injury. Practices such as close spacing and planting under the canopy of older trees may also help reduce tip moth populations and subsequent damage. Insecticides are an effective method for managing pine tip moths when applied in a timely manner...preferably as soon as the eggs hatch. Once larvae bore into buds and twigs, it is difficult to control them with sprays. Preventive spot programs should begin in late March with applications repeated on about a 20 day schedule until late June. There are 4 to 5 generations of tip moths per year, but first brood is generally the most damaging. See Fact Sheet EPP-7645 for more details on pine tip moths and monitoring with pheromone traps.

A potential disease problem early in the season is Diplodia Pine Tip Blight. This fungal disease attacks the plants through small openings in the young needles called stomates, or may also infect the tree through wounds in the bark. Growth from blighted terminals is usually stunted, the needles turn brown, and the terminal buds exude an excessive amount of resin. Diplodia can also infect the cones of older pines and the minute black fruiting bodies can easily be seen on the scales of the cones.


This fungal disease can seriously attack pine seedlings in nurseries, causing a rot that starts below the soil line in the collar area of the stem and extends upward into the main stem. Unfortunately in this case, the tree cannot be treated successfully. Diplodia Tip Blight on older trees can be controlled by pruning and sanitation. As soon as blighted terminals and cones are noticed, the needles, twigs and cones should be pruned to healthy tissue and destroyed. Do not prune when the branches are wet because the conidia of the fungus can easily be spread when moisture is present. Where infection has been severe, the use of Bordeaux mixture or Copper Fungicide 4E will control this disease. It should be applied early in the spring, when the buds open, and twice more at weekly intervals until the needles break through the needle sheaths. And, as with other trees, maintaining vigor through watering and fertilizing will go a long way in prevention.


For more information about potential Pine Tree problems click here.  



Question: My tree's roots are forming a circular area under the tree and my tree lacks vigor. What has caused this?

Answer: This picture shows a problem with root girdling. Roots are forced to grow around the main stem of the tree and cut off or restrict the movement of water, plant nutrients and stored food reserves. Over time, growth of the branches on the side of the plant most affected by the girdling will be slowed. As injury progresses, leaves will become smaller and lighter green, fewer leaves will be produced, and eventually the branch will begin to die back. Death of the entire plant can occur in five to 20 years. Watering, fertilizing and pruning will do little to correct the problem.


Development of girdling roots is not well understood but is normally thought to be the result of unfavorable conditions which prevent roots from growing out away from the trunk in a normal spreading manner. A good example is a container-grown plant, where the roots are often forced to grow in a circular fashion. If these trees are not pruned and spread out at the time of transplanting, this growth pattern can cause girdling roots. Restricted root space, such as tree pits in urban areas, also may result in girdling roots. A simple diagram of how to correctly plant a tree can be found here.

Certain trees are more prone to this problem than others. Lindens, magnolias, pines, and maples other than the silver maple are susceptible to root girdling. Normal trees have a gentle trunk flair or buttress at their base (Fig. 1). Trunks that grow straight up from the ground as though they were a telephone pole can be suspected of having girdling roots (Fig. 2). Trunks with a straight side or a concave depression on one side may also have a girdling root (Fig. 3).


For plants susceptible to root girdling, an inspection should be made when the tree is approximately six inches in diameter. A positive diagnosis can only be made by exposing the roots. Carefully remove the soil to a depth of at least 12 inches, taking care to prevent serious mechanical injury to the roots. If girdling roots are found on a plant with known susceptibility, the girdling root must be removed using a chisel or saw. While removing a girdling root will wound the tree and may ultimately kill it, the likelihood of the plant dying is greater if no action is taken.   


If the inspection reveals significant girdling and a considerable amount of damage, the most prudent move may be to replace the tree. Spending money on a weakened tree which subsequently dies can be an extremely frustrating experience. Since correction of this problem is so labor intensive, the costs and benefits should be weighed carefully prior to making any decisions.


Click here to send your question to the Tulsa Master Gardeners or see Answers to other Questions on the Web site