July 2015 / Volume 100       

In This Issue

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

80 degrees 


Rainfall total last 30 days:  

7.22 inches


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

Ann Bell (in memory of Warren Wirth)


Lindsay Hunt (in memory of Warren Wirth)


Diane Erbacher (in memory of Paul Padilla)



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: www.tulsamastergardeners.org 

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.

July Garden, Lawn & Landscape Tips
  • Make fall vegetable garden plantings in late July. Fact Sheet HLA-6009 gives planting recommendations.
  • 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.
  • Divide and replant crowded Hybrid iris (Bearded Iris) after flowering until August. 
  • 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 1 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. 
  • Control bermudagrass around trees and shrubs with products containing sethoxydim, fusilade or glyphosate herbicides. Follow directions closely to avoid harming desirable plants.

  • Water plants deeply and early in the morning. Most plants need approximately 1 to 2  inches of water per week.


  • Expect some leaf fall, a normal reaction to drought. Water young plantings well.

  • The hotter and drier it gets, the larger the spider mite populations!

  • Insect identification is important so you don't get rid of the "Good Guys." (EPP-7307)

  • Providing birdbaths, shelter and food will help turn your landscape into a backyard wildlife habitat.


Want to Become a Master Gardener?

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 training program for new Master Gardener Volunteers is offered once a year beginning in early September and ending in early December.

For those interested in 2015 training, two orientations will be held at the Tulsa County OSU Extension Center located at 4116 E. 15th St. 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.  For further details, visit 


Master Gardener Program: Tulsa Blooms

Tulsa Blooms

After a wet start (but we're not complaining!), Tulsa Blooms is back in full swing.  We have now placed over 100 pots, 88 pots in the Brookside area and 23 pots in the Blue Dome district.  Tulsa Blooms is a beautification effort to give the community a homey feel with beautiful, flowing petunias to soften the brick, glass and concrete. The feeling is contagious as we are receiving calls from merchants requesting pots and others taking it upon themselves to add their own planting schemes to supplement our efforts.  All of the merchants tell us of the positive comments they hear from their customers, and our watering teams receive compliments as well.  What a great way to get the Master Gardener program in front of the public!


For the most part, the merchants in both areas have stepped up to take over the watering.  In some cases, they are even offering to install (with our help) drip-type irrigation systems. We still have teams checking the pots for moisture, pests, and fertilizer needs daily.


We look forward to expanding into other districts, as the various merchant associations see what an attractive addition the Tulsa Master Gardener efforts can lend to their areas.

 Tulsa Blooms


Crapemyrtle (Lagerstomia indica)


  Crape Myrtle

A deciduous shrub or small tree that blooms from mid-summer to frost in full sun and is drought tolerant.  The Tulsa area is at the uppermost limit for cold-hardiness so it may suffer freeze-damage during severe winter temperatures, but will usually come back at the base.  Do not fertilize after July in order to encourage winter hardening. People are encouraged to consider size in their choice of plant selection instead of using severe pruning to keep the crapemyrtle the size that they want.


Pruning tip: Wait until new growth starts in the spring, then prune out the winter killed branches. DO NOT prune tree forms back to little sticks. This will create knobs and make the growth more susceptible to breakage because of wind and heavy flower set.


Here is a list of common crapemyrtles available in our area according to size and color:



Rosey Carpet - pink - 1 ft.

Violet Filli - purple - 1 ft.

Red Filli - red - 1 ft.

Baton Rouge - red - 2 ft.



Tightwad - red - 2-3 ft.

Pocomoke - pink - 3 ft.

Centennial purple - 3-4 ft.

       Cherry Dazzle - red - 3-5 ft

Dwarf Victor - red - 3-5 ft

        Mandi - red - 3-5 ft.

Dwarf Pink Ruffles - pink - 4-6 ft.

Dwarf Royalty - purple - 4-6 ft.

        Dwarf Snow - white - 4-6 ft.

Velma's Delight - magenta - 3-6 ft.



Hopi - pink - 6-8 ft.

Acoma - white - 8-10 ft

Siren Red - red - 8-10 ft.

White Chocolate - wine - 8-10 ft. 



Burgundy Cotton - white - 10-12 ft.

        Catawba - purple - 10-12 ft.

Dynamite - deep red - 10-12 ft.

        Pink Velour - deep pink - 10-12 ft.

Raspberry Sundae - red to pink - 10-12 ft.

        Rhapsody in Pink - pink - 10-12 ft.

Sioux - pink - 10-12 ft.

        Royal Velvet - pink - 10-12 ft.

Twilight - purple - 10-12 ft.

        Burgundy Cotton - purple - 10-12 ft.

Arapaho - red - 12-15 ft.



Red Rocket - red - 12-15 ft.

Muskogee - purple - 15-20 ft.

        Natchez - white - 15-20 ft.


Poison Ivy ( and Poison Oak)


{Poison Ivy}


In Oklahoma, we have one variety of poison oak, called Atlantic poison oak (PO), but it is not nearly as common as poison ivy (PI). They share many similarities and both have the capacity to cause severe allergic rashes in about 85% of the population.  There is a third plant in the "poison" group, called poison sumac. It is not present in Oklahoma, but mainly limited to the West Coast.


Some of the keys to identifying PO and PI are interchangeable. They both have leaflets of three to a stem. The leaflets and stems are distributed on the plant in an alternating fashion, they are not opposite one another where they originate. Likewise, the leaf veins are not opposite, but alternate where they connect in the center of the leaf.  Of the three leaves, the middle one has a much longer stem than the other two. If leaves have no stems, it is a different plant. The stems of PI are almost always reddish, a helpful ID point.  The leaf size and shape are very variable for PI, but PO typically has a shape similar to a white oak, with scalloped edges, and may be 6 or more inches long. Both plants are extremely colorful in the fall.  Both PI and PO have small off-white flowers which produce white pea sized berries. If berries are red, blue or purple, it is not one of these. Each of these plants can grow as a shrub several feet tall. PI may form a vine, but not PO. The PI vine may be an inch or more across and almost always has dense hair-like aerial rootlets for attachment to trees. Vines grow straight up a tree; if the vine twines or circles a tree is not likely PI.


In winter, identification is difficult.  If berries are still present, this helps, but an expert is required to identify bare stems.  It should be kept in mind that the toxin in these plants, called "urushiol", is present in the stems and fruits of both plants in all seasons and is capable of causing the typical rash.


Master Gardeners are often asked to identify a plant as to whether it is PI or not. There are several plants which may have 3 leaves or other characteristics causing confusion with PI and PO.  Some plants often having 3 leaves are bladdernut shrub, boxelder tree sprouts, aromatic sumac, skunkbush sumac and wild blackberry.  Other plants which may form vines and can be confused with the poisonous ones are Virginia creeper (five leaves), wild grape and both Boston and English ivy.



{Poison Ivy}


Insects: The Bad Guys


    {aphids on a tomato leaf}


 Harmful insects can destroy a garden in no time. They destroy in a number of ways...they such juices, pierce stems or fruit, chew leaves, and even cut stems.  An old garden adage states "Gardening is the art of growing flowers and crops for animals and insects to eat."  Although there is some truth to that, there are methods to keep at least the harmful insects at bay.  


Only 3% of all insects in your vegetable garden are harmful and will eat your plants. The rest are beneficial or harmless. Beneficial insects destroy the bad ones.  Try to use organic products and mechanical methods to kill these harmful insects without killing the beneficial ones.  This article is directed toward small backyard vegetable garden owners and, as such, it is easier to control small gardens by organic and mechanical means than large field crops.


If commercial insecticides are used, try to select the less harmful organics which are less harmful to the good insects.  Always read labels carefully!  Ask first if this product is really needed and is it safe for the environment.  There are quite a few organically-based products on the market.  There are oils (such as Neem Oil), soaps, microbials and ones derived from other plants, such as pyrethrins.  For crop rows, fabric covers help.  Even strong shoots of water from the hose will destroy many of the common pests. 


First, practice sanitation before planting.  Remove all plant debris and weeds as insects love to burrow under them and eggs are likely buried in the soil.  Some even overwinter there.  Tilling will destroy many insect eggs.  Companion planting, as discussed in OSU fact sheet HLA-6431, may be considered.  However, understand that much of the companion planting information is based on lore and not on science.  Another helpful cultural tip is to rotate crops, thus reducing the chance of insect and disease buildup.


Handpicking eliminates many harmful insects.  Many of the beetles, and especially slugs, feed at dusk and into the night.  If you are not able to pick at these times, send out your children or grandchildren.  They will love using a flashlight at night.  Be sure to look on the underside of leaves for residue and eggs. Be sure to inspect plants often for damage.


Use Integrated Pest Management (IPM) practices.  This is the practice of controlling pests by careful and regular inspection and using economic techniques.  This includes making the garden friendly to the good insects and to use pesticides only when absolutely needed.  Always try to use the least damaging pesticides in order to protect the good insects.  The "good guys" play a very big role in controlling the "bad guys".  Note: the beneficial insects work great in a greenhouse environment but are not effective outside as they simply fly away.


In summary, identify the insects.  Then, go online or to books for help, but be sure the help is based on proven research, such as from a university extension website (there is a lot of bogus info out there on the internet).  But, the best way is to simply contact the OSU Tulsa Master Gardener office at 918-746-3701 or on the online website.



{squash bug: adult and eggs}

Speaking of "Bad Guys" . . . Mosquitoes!


Don't let the bugs of summer keep you from enjoying your outdoor spaces this year.  Mosquitoes are not only pesky, but spread disease in humans, animals and birds.  If you understand just a bit about the life cycle of mosquitos, you can help to control or eliminate them.


Only the female mosquitoes bite.  One blood meal is sufficient for her to lay many eggs.  Immature stages of mosquitoes cannot develop without water in which to live and feed.  Therefore, the most important factor in preventing and controlling mosquitoes is to eliminate standing water.  This will help to reduce mosquito populations.  For elimination of larvae, treat temporary rain pools, intermittently flooded areas, tree holes and standing or stagnant water with a labeled larvicide.


Bugzappers, even though they are intended to control mosquitoes, may do more harm than good by attracting more mosquitoes from your neighbor.  They are non-selective as well, killing beneficial insects along with mosquitoes.  The use of standard insecticides is not a good solution as it will kill beneficial insects as well.  The best approach for control is for you and your neighbors to remove all standing water which might serve as breeding sites (see below).


Use of products containing Bt (Bacillus thuringiensis) are very safe and helpful.  They are most successful when applied early in the larval stage of insect life.  Larvae typically stop feeding soon after ingesting Bt and may take several days to die.  Regular applications may be needed throughout the summer until the weather cools.  Be aware that the standard Bt on garden center shelves will not help.  The Bt most commonly used for caterpillars is Bt Kurstaki strain, while the one useful for mosquitoes is Bt Israeliensis.  The Israeliensis strain is sold as mosquito dunks as well as other preparations.


Action Plan for Mosquito Prevention and Control:


1. Dispose of anything that can hold water, such as tin cans, containers and especially old tires.  Tires have become the primary breeding site in the United States.

2. Check uncovered junk piles.  Check around outside faucets and air conditioning units for puddles of water.

3. Clean and unclog roof guttering every year and check storm drains and window wells.

4.  Empty accumulated water from wheelbarrows, boats, cargo trailers, pet dishes, toys, ceramic pots and plant saucers.  If possible, turn these items over when not in use.

5. Do not allow water to stagnate in bird baths, ornamental pools, water gardens and swimming pools or their covers.  Swimming pools should be cleaned and chlorinated when not in use.  Water in bird baths should be changed every 2 days.

6.  Alter the landscape of your property to eliminate standing water.  Keep in mind that in warm weather mosquitoes can breed in any puddle.

7.  Adult mosquitoes prefer to rest on vegetation.  Elimination of weeds and frequent mowing will help cut down on mosquito populations.


Insects: And Now for The Good Guys


                 {Lady Beetle}                    {Praying Mantis}

Beneficial insects are those insects that not only pollinate our crops but also help in getting rid of many of pests found in the garden.  Their range is wide and often misunderstood.  The more we learn about them and use them, the better off are our gardens along with mother nature.


Beneficial Insects need a large amount of energy to carry out the pollination of plants and their destruction of pests, so they must have a large amount of flowers available to meet these needs. The planting of many flowering and diversified plants will lure these insects to the garden as well as helping to keep them in the garden.


How can you be sure that you have beneficial Insects in your garden and how do you identify the "Good Guys" from "Bad Guys"?   This can be done using the three "P's" for Beneficial Insects.  These are - POLLINATORS, PREDATORS, and PARASITES. Each has its own benefit by acting as mother natures best organic pest control.


1.   POLLINATORS, such as the honeybees, fertilize many flowers, increasing the productivity of many food crops, as well as feeding the Beneficial Insects.

2.   PREDATORS: like the lady beetle (bug) and soldier bugs, consume pest insects for food, thus eliminating pest from the gardens.

3.   PARASITES:  they use pests as nurseries for their young, thus getting rid of pests to be.


All three of the "P"  beneficial insects can be working at the same time in a diversified garden, thus helping you to control unwanted pests.  It is a much better choice of pest control since using many of the broad-spectrum herbicides can have a very negative effect on the "Good Guys", while getting the "Bad Guys".  And, as time progresses, many insects are becoming resistant to the chemicals being used, where as beneficial Insects will continue to help get rid of the "Bad Guys".


How do I determine if the insects I have in the garden are beneficial insects?  The following list are names for only a few:


Lady Beetles, Praying Mantis, Green Lacewings, Syrphid Flies, Damsel Bugs, Bigeyed Bugs, MInute Pirate Bug, Assassin Bug . . . just to name a few.


A longer and more complete list, as well as pictures, can be found in the OSU Extension Service Fact Sheet (EPP-7307) available online at our website or at our office.


    {Green Lacewing}                {Assassin Bug}


Pruning: Do's and Dont's


There is generally four reasons for pruning:


1. Prune to promote plant health


Remove dead or dying branches injured by disease, severe insect infestation, animals, storms, or other adverse mechanical damage.  Remove branches that rub together.  Remove branch stubs.  Avoid topping trees.  Removing large branches leaves stubs that can cause several health problems, and it also destroys the plant's natural shape and promotes suckering and development of weak branch structures.


2. Prune to maintain plants


Intended purposes in a landscape, such as: encouraging flower and fruit development, maintaining a dense hedge, maintaining a desired plant form or special garden forms.


3. Prune to improve plant appearance


Appearance in the landscape is essential to a plant's usefulness. For most landscapes, a plant's natural form is best.  Avoid shearing shrubs into tight geometrical forms that can adversely affect flowering unless it needs to be confined or trained for a specific purpose.  When plants are properly pruned, it is difficult to see that they have been pruned.  Prune to control plant size and shape, keep shrubby evergreens well-proportioned and dense, and remove unwanted branches, waterspouts, suckers, and undesirable fruiting structures that detract from plant appearance.


4. Prune to protect people and property


Remove dead branches.  Have hazardous trees taken down.  Prune out weak or narrow-angled tree branches that overhang homes, parking areas, and sidewalks - anyplace falling limbs could injure people or damage property.  Eliminate branches that interfere with street lights, traffic signals, and overhead wires. REMEMBER, DO NOT attempt to prune near electrical and utility wires. Contact utility companies or city maintenance workers to handle that job.  Prune branches that obscure vision at intersections.  For security purposes, prune shrubs or tree branches that obscure the entry to your home.


Trees and shrubs that bloom early in the growing season on last year's growth should be pruned immediately after they finish blooming, such as: Apricot, Azalea, Chokecherry, Flowering Plum, Forsythia, Lilac, Magnolia, Early Blooming Spirea.

Shrubs grown primarily for their foliage rather than showy flowers should be pruned in spring before growth begins, such as: 
Barberry, Burning Bush, Dogwood, Honeysuckle, Purpleleaf Sandcherry, Smokebush.

Shrubs that bloom on new growth may be pruned in spring before growth begins.  Plants with marginally hardy stems such as clematis and shrub roses should be pruned back to live wood. Hardier shrubs such as late blooming spireas and smooth (snowball) hydrangeas should be pruned to the first pair of buds above the ground.


Pruning Deciduous Shrubs


Recommended pruning for most deciduous shrubs consists of thinning out, gradual renewal, and rejuvenation pruning.  


Thinning Out: a branch or twig is cut off either at its point of origin from the parent stem to a lateral side branch to be "Y" of a branch junction, or at ground level.  Thin out the oldest and tallest stems first to allow for growth of vigorous side branches.  This method of pruning results in a more open plant and does not stimulate excessive new top growth.  Considerable growth can be cut out without changing the plant's natural appearance or habit of growth.  Plants can be maintained at a given height and width for years by thinning out.  This method of pruning is best done with pruning shears, loppers or a saw (not hedge shears).


Gradual Renewal: a few of the oldest and tallest branches are removed at or slightly above ground level on an annual basis.  Some thinning may be necessary to shorten long branches or maintain a symmetrical shape.


Rejuvenation: For an old and overgrown shrub, 1/3 of the oldest and tallest branches can be removed at or slightly above ground level before new growth starts.  When the shrub to be pruned is grown for its flowers, the pruning must be timed to minimize disruption of the blooming.  Spring flowering shrubs bloom on last season's growth and should be pruned soon after they bloom.  This allows for vigorous growth during the summer and to provide flower buds for the following year.


When to prune hedges?


Timing of pruning should take into account the potential for nesting birds.  However, in general, the optimum timing for pruning Deciduous and Evergreens Hedges:


Formative pruning:  In winter just after planting, and for the first two years after planting


Maintenance pruning:  Each Summer