August 2015 / Volume 101       

In This Issue

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

80 degrees 


Rainfall total last 30 days:  

5.48 inches


Donations Keep The Tulsa Master Gardener Program Going Strong
Recognition of this month's donations:


Ann McKellar (in memory of Shirley Ann Smith, widow of MG John Smith)


The Tulsa Master Gardener Foundation receives no city, state or federal funding for its programs. In fact, the majority of Tulsa's Master Gardener programs are self-funded. While we have many dues-paying members, income received from dues pays for less than 5% of total annual expenses. 

Tulsa Master Gardener's own fundraisers make up most of the income to cover expenses. A significant portion comes from the Tulsa Master Gardener annual plant sale that is held each April. Other fundraisers include the Garden Tour (June) and "garage sales" that occur from time to time. However, one other income source that sometimes gets overlooked is  personal and corporate donations.

To find out how you can help support all that the Tulsa Master Gardeners do for their community, contact the Tulsa Master Gardener office directly. 

4 Ways to Contact Us
Email us at:

See our website at: 

Call: 918-746-3701 from 9-4, Monday - Friday 
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

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.
Cool Season Lawn Care (Fescue)
12-month maintenance calendar.
Warm-Season Lawn Care (Bermuda)
Ditto above.
Trees for Tulsa
A list of recommended trees with descriptions.
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 each year. Register at our office on 15th Street 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.

August Garden, Lawn & Landscape Tips
  • August is a good month to start your fall vegetable garden. Bush beans, cucumbers, and summer squash can be replanted for another crop. Beets, broccoli, carrots, potatoes, lettuce, and other cool-season crops can also be planted at this time. (HLA-6009)
  • Soak vegetable seed overnight prior to planting.  Once planted, cover them with compost to avoid soil crusting.  Mulch to keep planting bed moist and provide shade during initial establishment.  Monitor and control insect pests that prevent a good start of plants in your fall garden.
  • Continue protective insect applications on the fruit orchard.  A good spray schedule is often abandoned too early.  Follow directions on last application prior to harvest. (EPP-7319).
  • Water compost during extremely dry periods so that it remains active.  Turn the pile to generate heat throughout for proper sterilization.
  • Always follow directions on both synthetic and natural pesticide products.
  • Watch for high populations of caterpillars, aphids, spider mites, thrips, scales and other insects on plant material in the garden and landscape and treat as needed. (EPP-7306).
  • Water all plants thoroughly unless rainfall has been adequate.  It is better to water more in depth, less often and early in the morning.
  • Grassy winter weeds like Poa annua, better known as annual bluegrass, can be prevented with a preemergence herbicide application in late August. Water in the product after application. (HLA-6420).
  • Tall fescue should be mowed at 3 inches during the hot summer and up to 3½ inches if it grows under heavier shade. (HLA-6420).
  • For areas being converted to tall fescue this fall, begin spraying out bermudagrass with a product containing glyphosate in early August. (HLA-6419).
  • Irrigated warm-season lawns can be fertilized once again; apply 0.5 lb N/1,000 sq ft in early to mid-August.
  • Brown patch of cool-season grasses can be a problem. (HLA-6420).

  • Towards the end of the month, divide and replant spring-blooming perennials like iris, peonies, and daylilies if needed.

  • Discontinue deadheading roses by mid-August to help initiate winter hardiness.
  • Watch for second generation of fall webworm in late August/early September. Remove webs that enclose branches and destroy; or spray with good penetration with an appropriate insecticide.


Want to Become a Master Gardener?

If you enjoy gardening, learning about gardening and have an enthusiasm for sharing your knowledge with others, the OSU Tulsa County Master Gardener program may be for you.


The Tulsa Master Gardener program is looking for active adults that enjoy interacting with people, get along well with others, are life-long learners and are ready, willing and able to volunteer their time to enhance the numerous Master Gardener community outreach programs. The 3-month training program for new Master Gardener Volunteers is offered once a year beginning in early September and ending by mid December.

For those interested in 2015 training, two orientations will be held at the Tulsa County OSU Extension Center located at 4116 E. 15th Street in Tulsa.  The first one will be held at 1:00 p.m. on Wednesday, August 5th; the second one will be held at 10:00 a.m. on Wednesday, August 12th.  These orientation sessions will review the Master Gardener program and requirements to enter this year's class. This includes costs for the classes and agreement for volunteer hour participation after training is completed.


If you are still interested following the orientation, an interview time can be scheduled.  If you are accepted into the program, the first class is September 2nd, with other classes each subsequent Wednesday through December 16th. These classes offer over 70 hours of instruction by OSU faculty and extension horticulturists.


The classes will give you a good background in horticulture and prepare you to confidently deal with most gardening problems and questions.  Not only will you learn a lot, but you will make many new friends and join the group of over 375 active Tulsa County Master Gardeners.


No previous horticultural training or education is required to enter the Master Gardener program as training starts with the basics. We welcome you to come to an orientation session to learn about the program, as it may be the perfect fit for your volunteer activity.  For further details,visit


Master Gardener Program: 
Demonstration Garden

The Demonstration Garden surrounds the OSU Tulsa County Extension Office on 15th Street between Yale and Harvard (at the Fairgrounds #6 gate).  The garden allows us to see what grows in our soil and climate, and serves as a test area for new plant material.  Oklahoma Native and Oklahoma Proven trees, shrubs and plants are becoming a prime focus to use in home landscaping because of the ever changing weather conditions in our state.


The garden is divided into different growing habitats including Xeric (drought tolerant) plantings, butterfly, sun loving, shade tolerant, pond plants, herbs, raised-bed vegetables, and fruit bushes and trees.  We are excited to show off our brand new Compost Demonstration Area located on the south side of the parking lot between the two metal buildings.


Besides landscaping ideas, we also demonstrate how hardscapes and water features can enhance a garden.  We have over 400 varieties of plants, trees and scrubs.  All are uniquely identified by metal markers (with both common and botanical names) and an annually updated plant list that is available in INFO boxes throughout the garden.


Teams of our Master Gardener volunteers maintain the Demonstration Garden on a weekly basis throughout all of the growing season.  We would love for you to stop by and walk through our gardens.


So, Just How Wet Is It? 


I'm sure we are all wondering just how we have followed up one of the wettest months Tulsa has ever seen. The short answer is, it's still wet, Thanks in large part to the remnants of Tropical Storm "Bill", and some well-placed heavy rainfall to start July. If we look at the 83 day period from May 1 through July 21 this year, Tulsa has seen a whopping 25.83 inches of rain...for comparison sake our annual average is just over 40 inches. The record book shows that to be the rainiest such period on record (since 1893 anyway). It is interesting to note that both 2007 and 2008 rank in the top 5 wettest, even though that seems like eons ago given the drought that plagued us for the past 5 years.

Speaking of drought, it's worth mentioning that absolutely ZERO percent of Oklahoma is currently in drought. The last time we saw that was way back in May of 2010! Hopefully now, the rest of the year is kind to us and we can remain drought-free for a while.


Is There A "Major" El Niño Developing?


By now, I bet many of you have heard rumors of a strengthening El Niño in the Pacific Ocean, which has begun to draw comparisons to other great El Niños past, namely the super-colossal El Niño of 1997-98, which was indeed one of the strongest recorded. Observations continue to show it gaining strength, and while it is way too early to start predicting a historic event, most forecast guidance shows this one reaching at least moderate strength, and many model solutions pointing to a strong event.

History has shown that strong El Niño events increase the odds of (but do not guarantee) above normal precipitation across much of the southern United Sates, including Oklahoma, during the "cool" season. This will be something to watch in the coming months, and if it pans out, could mean more wet weather through the end of 2015. Stay tuned!


Rain, Rain, Rain . . . Then, Mold and Fungus


Ok, so we've clearly established that the Tulsa area has had an abundance of rain lately.  As of the middle of July, our month-to-date precipitation is 4" above normal and our year-to-date precipitation is 12.5" above normal.  Tulsa area lakes are averaging 11.4' above normal and the Port of Catoosa shipping volume is down by approximately 50% due to the high water.  Our multi-year drought has now officially been broken, basically across the entire state.  However, we need to consider the effects of this much rain on our landscapes.


Plant roots need water, but they also need oxygen which they get from the air.  If soil is "waterlogged" and the spaces or pores between soil particles are filled with water, plants do suffer.  Particularly vulnerable are those areas where the water table is high or where soil is compacted and thus poorly structured.  Wet soil is often low in certain nutrients (notably nitrogen) and, as a result, mineral deficiencies may prove a problem.  Diseases flourish in this situation.  Roots growing in waterlogged soil may die primarily because they cannot absorb the oxygen they need to function properly.  Plants growing in water logged soil become stunted, grow slowly, weaken and may die.  If totally deprived of oxygen by wet soil, some plants may suffocate and die within days.  In addition, if plants do survive, they have less resistance and are much more likely to develop disease and insect problems.


Heavy and poorly drained soils are especially susceptible to becoming waterlogged.  Poor drainage may be confirmed by pouring water into a hole that is 12-24 inches deep.  If the water remains for hours, the soil needs more drainage.  This can be accomplished by French drains, drainage ditches or soakaways (a soakaway is a gravel-filled pit into which excess water runs via underground drains or drainage ditches.  Draining water slows down when it reaches a transition between finer and coarser soils, no matter which lies above the other, and perches in the soil immediately above the transition zone.  Water doesn't spread far laterally through soil, except when running down a slope.  A symptom of over-watering is roots concentrating just under or just above the soil surface where soils dry out faster and oxygen is more available. 




What are fungi?  They are members of the Thallophytes or lowest plant group.  Fungi are the most common cause of infectious plant diseases.  Lacking the power of manufacturing their own plant food, they live as saprophytes on decaying plant tissue or as parasites on higher living plants.  They are characterized by a vegetative state consisting of fungus threads, or mycelium, and fruiting bodies which contain the reproductive organs.  Some fungi are readily recognized at a glance: mildew, with its white weft of mycelium growing over a leaf; rust, which produces reddish dusty spores; and smut, with its masses of black spores.  Powdery mildews are known to occur on almost all ornamental plants.  In Oklahoma, powdery mildews are common on ash, crape myrtle, lilac, oak, photinia, roses and zinnia.


If you are interested in learning more, recommended reading in the OSU Master Gardener library: 10,000 Garden Questions; Home Gardener's Problem Solver; Southern Living Garden Problem Solver; and Ortho Home Garden Problem Solver.



Bees: Angels of Agriculture



Remember when we were kids, running around outside with carefree abandon as we played our favorite games?  That is when we first became acquainted with bees.  We would unknowingly tromp through their little homes and nectar/pollen air routes, and receive our annual bee sting.  Bees became the bad guys.


But, as we have gotten older, we figured out how to avoid stings and understand they are really the good guys, called "Angels of Agriculture" by some.  And, for good reason!   Did you know that about one-third of the food we enjoy results from bee pollination?


Without bees, fruits, vegetables and nuts would not mature. The same thing is true about alfalfa and clover crops, which are needed by livestock (meat and dairy).  Bees also pollinate oilseeds and cotton crops.  And, then there is honey, which has rightfully earned its reputation as a whole food and medicine.  The list is long, and affects much of what we need to survive.


But wait!  Bees have other talents...they can be used as "sniffer bees" to locate explosives, drugs, and diseases.  Some scientists claim bees are better sniffers than dogs!  When bees are exposed to a specific smell and given a sugar reward, they stick their tongue out to receive it.  More specifically, trained bees are housed inside a hand-held detector. When they recognize a particular scent, like illegal drugs or bomb ingredients, they stick out their tongues.  The response is then recorded by computer software which identifies the substance.  


Regrettably, we are now learning that bees are having a rough time surviving in the modern world.  Bees have been around a long time and can withstand a lot of stress as long as they have nutrition resources and habitat.  Bee fossils, millions of years old, have been discovered.  Egyptian tombs are adorned with bee pictures; cave paintings of beekeeping exist in Spain dating back to 7,000 BC; and, the Roman Empire valued honey over gold as currency. 


Bees have had an amazing journey to have made it this far.  But, since about 2007, bees are being affected by a sort of perfect storm, consisting of parasites, varroa mites, pathogens, colony collapse disorder, poor nutrition (mono-crops, artificial nectar), pesticides, urbanization, and changing weather patterns.  They continue to die and disappear in larger-than-average numbers worldwide.


We are talking 4,000 species of bees, not just fuzzy honeybees.   They don't all make honey, but they are all pollinating dynamos, like the mason bee. 


You can help out in a big way by doing just a few little things: 

  • Plant more single-petal flowers (blue, purple, pink, yellow).  Bees are insensitive to red.  A few of bee's favorites include: asters, anise hyssop, borage, clover, cosmos, crocuses, hyacinth, sedum, coneflower, Shasta daisies, dahlias, foxglove, geraniums, hollyhocks, hyacinth, marigolds, poppies, phlox, roses, snowdrops, sunflowers, blackberries, cantaloupe, eggplant, cucumbers, gourds, cherry trees, peppers, pumpkins, squash, strawberries, watermelons, bee balm, catnip, cilantro, fennel, lavender, mint, rosemary, sage, thyme, alyssum, black-eyed susan, butterfly weed, yarrow, Russian sage, marigolds, snapdragons, crepe myrtles, zinnias. 
  • Plant in groups (3' x 3') - it's easier for bees to locate them and shortens distances traveled to collect pollen and nectar
  • Plant flowers that bloom early (crocus, hyacinth, borage, calendula, and wild lilac) and in fall (zinnias, sedum, asters, witch hazel, goldenrod) - for continued food supply
  • Bees are wild about dandelions!
  • Try a patch of perennial wildflowers
  • Vegetable garden
  • Provide water (shallow plates/pans give them a landing strip) - near flowers, if possible
  • Provide a little wet dirt or mud, for nest building
  • Flowering hedgerows are meccas for bees, providing both food and shelter
  • Clover patches delight bees, which withstand hot, dry conditions
  • Pots and planters work well for smaller yards or balconies
  • Pollinators are least active after dusk, making it best time to spray, if you must
  • Seek out chemicals that do not harm pollinators
  • Construct bee houses - the internet is full of inexpensive DIY ideas
  • Amateur beekeeping, scaled down for backyards
  • Engage kids in bee projects - get them educated and interested
  • Share tips with others
  • Note that these tips apply to all pollinators: butterflies, birds, wasps, etc.
And, now for a little information you probably didn't know about our friend, the bees:


Wouldn't it be great to know that your local bees are doing the "waggle dance", telling their fellow bees where your garden is every summer?


A few OSU Fact Sheets to learn more:


Honeybees, Bumblebees, Carpenter Bees, Sweat Bees (EPP-7317)

Nectar and Pollen Plants in Oklahoma (EPP-7155)

Africanized Honeybee in Oklahoma (EPP-7325)

Household Pest Control (EPP-7312)

Safe Use of Pesticide in Home and Garden (EPP-7450)


Fall Webworms: 

Now Holding Spinning Classes


Those ghostly nests over the ends of tree branches are fall webworm caterpillars.  Despite their name, they started spinning their nests in May.  Now, in late summer those nests are larger because the second generation of larvae have stripped the leaves down to their spines and have left ugly debris in our trees.


The bad news is the caterpillars are known to attack 88 species of Oklahoma trees.  And they enlarge their nests to encompass more leaves to eat as they only eat inside their protected nest.   This pest has two generations each year.  The second one (the one we are seeing now) is generally more visual and damaging.


The good news is that as long as the tree is established and healthy, it should survive and produce lush branches next spring.  Rarely do fall webworms defoliate entire trees. The caterpillars eat only the soft part of the leaves, and avoid the spine, twigs and branches so regrowth can occur.


Larvae and Moths


This pest overwinters as a pupa in a cocoon that is concealed in ground litter, cracks, and crevices in the soil. Adults first appear in mid May.  The females deposit eggs on the under-surface of leaves.  Larvae then hatch in seven days.  They immediately begin to spin their silken web over foliage.  Nests can grow up to three feet in diameter on an infected branch.  The larvae love each other's company and feed together in the nest until they mature into white moths.  The larval stage is the most destructive.




With the exception of smaller tress during heavy infestations, most deciduous trees are able to withstand a feeding event.  Damage is mostly aesthetic, and control is not typically warranted except in the case of pecan orchards and tree nurseries.


Various species of natural enemies help to manage this native insect.  Birds and insect predators and parasitoids attack the larval stage.  Predators may also destroy eggs.


If the nest is within reach and you feel you must do something, we have a few suggestions:




If the webbed branches are within reach, they can be pruned and destroyed if the aesthetic shape of the tree is not compromised. 


If you don't want to prune but can reach the nest, you can break it up by hand with a broom or pole with nail sticking out.  Break up and destroy the webbing.  Hungry larvae will have to stop and re-spin their protective tent before they can eat again.




In serious cases, you can apply an insecticide labeled for webworms or defoliating caterpillars.  Push the applicator wand through the webbing so the spray will make contact with the worms and the leaves they eat.


If you decide to use an insecticide (and most people don't), consider using a safe organic insecticide such as Bt, as found in the brand Thuricide. It is widely available and is safe for you, your pets, and the good insects.  Other organics such as horticultural oil (Neem would be a good choice) and pyrethrin are recommended. 


Be sure to read and follow all label directions before each use to maximize efficacy, prevent phytotoxicity and minimize adverse environmental impacts.  Note the insecticide will not destroy the silky web which will remain in the tree until it naturally degrades during the following winter.


For severe infestations out of your reach, contact a reputable lawn service.


Mimosa Webworms -  double time spinners


A native of China, the Mimosa webworm can defoliate mimosa and honey locust trees.  Damage from their second and third generations can be severe and unsightly.  The insecticides mentioned above can be applied.  It is not advisable to make a large planting of mimosa or honey locust trees unless you make plans for chemical control.



Pesticide Effectiveness


Ever wonder why pesticides don't seem to quite as effective as they should be?  Well, there can be a number of reasons for this lack of efficacy. Here are some of the common ones:


     1. Lack of good foliage penetration.  This often is a problem when spraying for bagworms on junipers.  The spray must penetrate the foliage and reach the bagworms toward the inside of the plant.  High-pressure commercial sprayers are able to get the spray to the insects, but homeowner models are much more problematic.  With pump-up sprayers, you may have to push the wand through the outer layer of foliage to reach insects toward the inside of the plant.

     2. Not spraying where the insect is. Many of our insects and mites feed on the underside of leaves.  If the plants are sprayed over the top, little to no pesticide actually reaches the pests. This problem is often seen with spider mites on broad-leaf plants and cabbage worms on cabbage, broccoli and cauliflower.

     3. Maturity of pest. Insects become much more difficult to control when they become adults. For example, Sevin does a good job of controlling young, early instar grasshoppers, but is much less effective on adults.

     4. Level of disease pressure. Most fungicides are better used as preventatives than as curatives.  If a disease gets firmly established, it may be difficult to bring it back under control.  For example, chlorothalonil is effective in controlling early blight and Septoria leaf spot on tomato if used as a preventative.  However, chlorothalonil will not control these diseases on badly infested plants.

     5. Choosing the wrong product. Homeowners often use a product they have on hand.  However, products differ markedly in how well they control specific pests.  Make sure the pest you wish to control is on the label.  Unfortunately, even labeled products may vary in effectiveness.

     6. High pH spray water. Certain pesticides are not stable in high or low pH water. The following are some examples.

     * Captan has a half-life of 3 hours at a pH of 7.0, but only 10 minutes at a pH of 8.0.

     * Carbaryl (Sevin) has a half-life of 24 days at pH 7.0, but only 1 day at pH 9.

     * Diazinon is most stable in pH 7 water, with a half-life of 10 weeks; at pH 5, it is 2 weeks.


The half-life of a product is the amount of time it takes for half of the product to be neutralized.  For example, if you apply 3 ounces of a product to a gallon of water and the half-life is 8 hours, only half of the product is still active at 8 hours, one-fourth of the product is active 16 hours and 1/8 of the product is still active at 24 hours.  


If you do choose to use pesticides, be sure to always read and follow all label directions.



Q&A: My red-tipped photinia developed brown spots last summer.  I was told this is a fungus.  Is there anything I can or should do for prevention?



Like many plants that are densely planted in a community, they tend to get disease.  In this case, it is a fungus called entomosporium leaf spot.  This is manifested by red to brown spots on young leaves that may progress to cause extensive leaf drop.  It usually does not kill the plant, but impairs growth and appearance.


It starts in the spring, but may not be noticed until summer damage is apparent.  The fungus over-winters in the leaves fallen to the ground the previous summer.


Effective treatments involves cleaning up all of the old leaves from the previous year to rid the plant of disease exposures.  In addition, if you wish to go to the effort and expense, there are fungicides that are effective if begun before the disease is established.  OSU recommends several fungicides as preventatives.  Contact the OSU Extension Office for recommendations.