May 2016 / Volume 110   

In This Issue

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

61-63 degrees 


Rainfall total last 30 days:  

5.92 inches

(Normal: 3.78 inches)



2016 YTD Rainfall total: 

9.48 inches

(Normal YTD: 10.59 inches)





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

MG Memorial Donations for Sally Sitler:

Judy & Rick Milroy
Diane & Nick Nail
Judith & Ed Payton
Allen & Christa Robinson

Other Memorial Donations for Sally Sitler:

Bryant Bank - Alabama
Dr. & Mrs. Richard O Russell, Jr - Alabama
Mary Noble - Tulsa
Patricia J. Meadows - Tulsa
Roy Thompson - Tulsa

MGs - Other:

Ann & Jim McKellar
Janet Newman
Dewayne Reeves

Other (for Exploring Insects Program): 

Cory Forister, EMTEC Pest Control - Tulsa
LawnAmerica, Inc. - Tulsa
Zoellner Exterminating - Tulsa
Howard Horticultural Services, Inc. - Tulsa 


Green Tree Assisted Living (for Senior Living Program)

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.

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. Finally, one other income source that sometimes gets overlooked are personal and corporate donations.  These are so important in helping to meet our financial obligations and are very much appreciated. 

You can make an online contribution by going to the Tulsa Master Gardeners website and donate directly through PayPal. For other information on how you can help support all that the Tulsa Master Gardeners do for their community, contact the Tulsa Master Gardeners Office by calling 918-746-3701.  Thank you! 

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.
May Garden, Lawn, & Landscape Tips



  • Plant watermelon, cantaloupe, cucumber, eggplant, okra, sweet potatoes, etc.
  • Fruit spray programs should be faithfully continued during the next several weeks.
  • Late May is the best time to control borers in the orchard.  Check for label recommendations and controls.
  • Clean out water garden and prepare for season. 
  • Divide and re-pot water garden plants.
  • Begin feeding fish when water temperatures are over 50�F.

  • Cool-season lawns can be fertilized again. If you did not fertilize cool-season grasses in March and April, do so now.
  • Warm-season lawns may be fertilized again in May. (HLA-6420)
  • Seeding of warm-season grasses such as bermudagrass, buffalograss, zoysiagrass and centipedegrass is best performed in mid-May through the end of June. The soil temperatures are warm enough for germination and adequate growing season is present to promote winter hardiness.
  • Dollar spot disease of lawns can first become visible in mid-May. Make certain fertilizer applications have been adequate before ever applying a fungicide. (EPP-7658)
  • Nutsedge plants become visible during this month. Post-emergent treatments are best applied for the first time this month. Make certain warm-season grasses have completed green-up.
  • The second application of pre-emergent annual grass herbicides can be applied in late-May or early June, depending upon timing of first application. Check label for details.
  • Vegetative establishment of warm-season grasses can continue. (HLA-6419)

  • Prune and feed azaleas immediately after blooming.
  • Insect Alert: (EPP-7306)
    • Bagworms on juniper and arborvitae. (Late May)
    • Elm leaf beetles and larvae on elms. (Late May)
    • Mimosa webworms on mimosa and honeylocust.
    • Lace bugs on sycamore, pyracantha and azalea.
  • Soak new transplants and newly planted trees unless rainfall is abundant.
  • Pine needle disease treatments are needed in mid-May.
  • Annual bedding plants can be set out for summer color.
  • Plant summer bulbs such as cannas, dahlias, elephant ear, caladiums and gladiolus.
  • Shake a leaf over white paper to look for spider mites.  If the tiny specks begin to crawl, mites are present.

MG Program: Tuesday Evening Classes

Each year in the Spring, the Tulsa Master Gardeners conduct informal classes every Tuesday evening during April and May to help educate the public on research-based horticultural information.  This year is proving to be every bit as good as in the past, with an impressive list of popular subjects, as follows:

April 5th      Butterfly Gardening
April 12th    Sun Loving Annuals and Perennials
April 19th    Herb Gardening for Dummies
April 26th    Shade Gardening with Annuals and Perennials
May 3rd       Planting for Pollinators: Bees, Butterflies, etc.
May 10th     Keeping Critters under Control - IPM in the Garden
May 17th     Straw Bale Gardening - Grow Anywhere
May 24th     What's the Deal with Native Plants?
May 31st      Made in Oklahoma - Native Trees & Shrubs

The classes are open to the public, they are free, and you can come as you are.  They begin at 5:30 p.m. and generally last 30 minutes, until 6:00 p.m.  However, the speakers hang around as long as there are questions and there is interest.  The programs are held in the large classroom of the OSU Extension Office located at 4116 East 15th Street in Tulsa (enter at Gate #6 of the Tulsa County Fairgrounds off 15th street).  See you there!


MG Program: Tulsa Blooms!
Tulsa Blooms
Large pots spilling with bright colored flowers and thrilling grasses shooting to the sky line the sidewalks on 36th Street in Brookside and the Blue Dome district near downtown Tulsa. Over 100 of these pots were provided by Tulsa Master Gardeners to give beauty and interest to these shopping areas. The pots also intended to inspire the merchants and visiting homeowners to provide and care for their own plant decorations.

Tulsa Master Gardeners named this project Tulsa Blooms. They planted their first flower pots in 2010 in front of Channel 2 news in Brookside.  Other merchants on 36th Street became interested and now most shopping centers, stores, and restaurants on the east and west side have decorative pots in front of them.  Many of these pots are now maintained by the shop owners themselves.  The year 2015 began the expansion of Tulsa Blooms to the downtown Blue Dome area.

In the beginning, the pots were filled with Canna plants as centerpieces and surrounded by a variety of colorful annuals. After awhile, the Cannas took over and dwarfed the smaller flowers. The next attempt was to plant purple feather grass as the focal point, surrounded by bubblegum pink supertunias. This was a pretty combination and used for a time, but the Oklahoma wind blew the purple fountain grass and tipped it to one side. Master Gardeners then decided to dig up the purple fountain grass and plant the more upright evergreen boxwood surrounded by pink supertunias.  It was during the time of the boxwoods that Tulsa Blooms won an Oklahoma Beautification award in 2014 as well as over ten other street garden designs in Oklahoma.  Master Gardeners were then awarded with iron benches with Tulsa Blooms inscribed on them.  Several of the benches were set next to the blooming pots. 

Every day during the hot months of summer Master Gardeners will take turns watering some of the pots but each year, more and more merchants water their own pots.

Come October, large teams of Master Gardeners will gather to pull the supertunias and add pansies. In April of every year, the pansies will be pulled to add the summer flowers.  So the beat goes on, spreading more pots through Tulsa and inspiring citizens and merchants to make the city more beautiful through nature.

Proper Mulching Techniques
As you look around town, you will find so many opportunities to provide trees, shrubs and flower beds mulch.  Mulching has many benefits, such as:
  • Helps to reduce moisture loss due to evaporation
  • Cools the plant roots in Summer (and warms in Winter)
  • Minimizes grass and weed germination and growth
  • Provides beneficial nutrients (organic types)
  • Protects trunks from lawn equipment damage
  • It looks nice!
Mulch is available in a variety of forms; organic and inorganic. Inorganic much includes pulverized rubber, lava rock, different types of stone, geotextile fabric and other materials. Inorganic mulch does not decompose and does not need to be replenished often.  However, this type of mulch does not improve soil structure, provide nutrients or add organic materials and most horticulturists and arborists prefer organic mulches.  Organic mulch includes wood chips, softwood bark, cocoa hulls, leaves compost mixes, pine needles and other products typically derived from plants.  These mulches decompose in the landscape at various rates, depending on the material, climate and the different microorganisms present.

However, there is a tendency to misuse this beneficial landscaping resource.  The single biggest complaint related to mulching is a technique referred to in the landscaping industry as "volcanic mulch", as shown here:

(What NOT to do!)

When mulch is piled high against the trunk of a young tree, it may create habitats for rodents that chew the bark and may cause girdling of the tree.  Because there is much to gain from mulching, follow these application methods to ensure the proper health of your landscape plants:
  • Make certain there is proper soil drainage
  • Use the correct mulch for your plant material
  • For well drained sites, apply only 2-4 inch layers.  If poorly drained, apply less.  Coarse mulches can be applied slightly deeper
  • Place mulch out to the edge of a tree's crown or beyond
  • If mulch is already present, check for depth.  If sufficient mulch is present, break up any matted layers with a rake and apply a bit more to refresh the look
  • If mulch is piled against the stems or tree trunks, pull it back several inches to ensure the base is exposed
  • Avoid using fine, non-composted wood chips so that soil nitrogen is not taken up by the roots as the wood chips decompose

The Basics of Vegetable Gardening
With cloudless skies and warmer weather, thoughts turn to the joys of summer eating . . . fresh tomatoes, bold jalapenos, juicy strawberries, and the challenges of growing a garden in Oklahoma.
As with most worthwhile projects, planning is one of the key elements of gardening success.  Selecting and preparing the gardening site is the first step.  The site should receive full or nearly full sunlight for six or more hours per day.  The soil should be fertile and well-drained, with a water supply close by.  If the soil is thin or poorly drained, raised beds should be considered. Organic material (compost) should be utilized when available and, after planting, using mulch can help conserve moisture and control weeds.

There are some crops, (beans, beets, peas, spinach and others) that will tolerate areas with light shade or bright, airy places with only one or two hours of direct sunlight.  Unfortunately, few vegetables will grow well under full, dense shade.  To help ensure a productive garden, soil should be sampled and tested every three to four years.  Fertilizers and other amendments should be used in appropriate amounts and at appropriate times.  The garden should be frequently examined to keep ahead of potential weed, insect, or disease problems.

Many gardeners like to plant hardy vegetables (those planted early in the season) together so they may be followed with another late season planting.  By planning and planting in succession, the garden should be constantly filled through the summer months with tempting tastes and sights.
For more information about what and when to plant, along with basic information concerning common garden problems, please see Oklahoma Cooperative Extension Service guide, HLA-6004.

lnsects (After a Warm Winter)
This past winter has been exceptionally warm, creating the possibility that we may have an unusually large insect population to deal with this spring and summer.  However, several studies show that there are some varieties of insects that will not make it through the warm winter due to being hatched earlier than when there was available sources of their food.  So, determining just how large of an increase we will get has been pretty tricky.  But, most outlooks feel that we will be faced with an increase, not only in our lawn and gardens, but also in our homes and on our pets.

Some expected large increase in insect populations include: ticks, spiders, fleas, beetles, cockroaches, and mosquitoes as well as termites, ants, white grub worms, caterpillars and (in the trees) the Eastern Tent Caterpillar.  Most of these will be making their appearance in spring and early summer.

Remember, when you start seeing insects and pests in your plants and in the house, please identify the types of insect before you start using an insecticide.  Ask yourself: is it a bad insect or a beneficial insect?  This is a very important step to take because many beneficial insects are a big help in getting rid of the bad insects in your lawn and garden.  And, spraying an insecticide without doing some research may result in the kill of many beneficial insects along with the bad ones.  This is why it is so important to make the identification before applying insecticides. 

If you need help in determining the type of insect (good or bad), you can go to our website or bring in the insect(s) or a picture thereof to the OSU Extension Office located on 15th street. Master Gardeners, along with the OSU Agricultural Agents, can help you to control your pest problems and offer suggestions on the care of the garden, trees or lawn.  Also, there are OSU Fact Sheets that are available with pictures of both the good and bad insects (in color).  We also have a listing of effective and favorable insecticides to take care of the "bad guys".

OSU Extension Website Resources: HLA-6433, EPP-7306, EPP=7307   

Milkweed & Monarchs
The Monarch butterfly is easily recognized with a black, orange, and white pattern and a wingspan of  3�-4 inches. Monarchs are considered beauties of nature and are native throughout the U.S., except for the arid parts of the west.
Monarchs are dependent on milkweed plants.  Milkweed plants serve as a host for their eggs and the caterpillars.  The caterpillars eat only milkweed.

Because of human activities, milkweed plants are on the decline in the U.S. and elsewhere.  Further, the population of Monarchs has declined as a consequence of the loss of milkweed. Various organizations in the U.S., including Tulsa Master Gardeners, have begun an intense drive to replant milkweed in butterfly-friendly areas.  This has become very popular with gardeners and environmentalists and the demand for information about milkweed, along with sources of seeds and plants, is high.

There are said to be 73 species of native milkweeds in the U.S. and about 30 of them serve as host plants for the Monarch.  These types of milkweeds are scattered across the U.S. in various ecological areas.  Oklahoma is thought to have about 20 native milkweeds.  Because of environmental requirements, some of the milkweeds in Oklahoma are limited in distribution to only 1-2 counties.  In the Tulsa region there are about 10 types of native milkweeds used by Monarchs.

As you consider planting milkweeds, remember one thing . . . Monarch caterpillars are voracious eaters and can rapidly strip a plant of leaves.  So, place several in your monarch-friendly area. Ideally, one Monarch egg/caterpillar should have an entire milkweed plant on which to eat and grow.  Withhold insecticides and pesticides from this area and offer other nectar plants, such as:
  • Blue Sage
  • Chia
  • Scarlet Sage
  • Mexican Sunflower 
  • Zinnia Dahlia Mix
All milkweed are perennial if planted in their preferred growing zone.  Once established, they should return yearly from the roots. These plants also produce a large number of seeds which can be collected for next year's planting.
Milkweed's milky sap is toxic to pets, birds and children if eaten. Some people also develop rashes upon contact with the sap. However, the toxin has no adverse effect on the Monarch butterfly.  Although Monarch butterflies do pollinate milkweeds as they draw nectar, pollination isn't their primary relationship. Monarchs mostly need milkweed as a host plant for its caterpillars. 

For information as to the types of milkweeds in Oklahoma and the counties in which they can be found, go to: Guide to Oklahoma�€™s Milkweeds for Monarch Butterflies This website also has suggestions about how to collect seeds.

Also, see this table for the different varieties of Oklahoma milkweed.

Hummingbirds: Choose Life in Your Garden
What a lively place your garden can be if you make it attractive to wildlife, and especially if you make it conducive to hummingbirds.  Hummers add movement, vitality and enjoyment to the garden experience and the entire family.  Of all the hundreds of bird species, hummingbirds are particularly interesting and delightful to attract to the yard.  These brightly colored jewels can provide hours of enjoyment through their dazzling flying abilities, acrobatics and bold personalities. 

Hummingbird Facts

The hummingbird is the smallest native bird in North America, length totaling about 3 � inches overall and weighing only about � of an ounce.   They are identified by the extremely rapid movement of their tiny wings that creates a humming sound as they fly or hover.  The average wingbeat of a hummingbird in flight is 55 strokes per second.

The metabolism of hummingbirds is also a distinguishing characteristic.  For its size, it surpasses all other warm blooded creatures in energy consumption.  On average, it must feed every 15 minutes during the day in order to survive.  Since it can't feed at night, it must either store up excess fat and carbohydrates prior to sunset or else go into a state of dormancy called torpor.  When becoming torpid, it drastically reduces its metabolism and thus its feeding requirements.

Hummingbirds have a long, split retractable tongue which allows them to extract nectar from blossoms.  With their tongue they exhibit a licking motion at the rate of about 13 licks per second.  The tongue has tiny fringes along the split edges that allow them to eat small insects that are trapped in the sticky nectar.  This adds needed protein to their diet.  They also can catch small insects when they are on the fly.
The two species of hummers most frequently seen in Oklahoma are the two that migrate the farthest.  They are the ruby-throated and, the less frequently seen, rufous hummingbird which may travel 2,000 miles or farther.  For the ruby throat, 500 of those miles are over the Gulf of Mexico over open water.

Supplying Hummingbird Needs

All birds need three things to survive . . . food, water and shelter.  Use a diverse selection of plant materials to provide food and shelter for birds, using native plants whenever possible.  Our native birds are adapted to the native plants, which are often drought resistant, cold and heat tolerant and many are proven bird attractors.  An additional benefit is that they are often low maintenance.

Use of flowering plants is very beneficial to hummingbirds.  They require a constant and diverse supply of flower on which to feed from April until late fall.  For best results, choose plants that like bright sunny areas.  The plants will give greater quantities of nectar given lots of sunlight and the hummingbirds will benefit from the sun's warming rays.

Hummingbird Feeders
  • Keep them clean.  In warm weather, they may require cleaning every two to three days.  Wash with a solution of one tablespoon of white vinegar to one cup water.  Rinse thoroughly.
  • Never use honey or a sugar substitute when making a nectar mix.  Honey will attract bees as well as a black fungus that causes disease in hummingbirds.
  • Do not use red food coloring in the nectar as it is unnecessary and unhealthy for the birds.  Besides, the feeder already has a red blossom port on it.
  • Use the following recipe to make the nectar and allow it to cool before filling feeder:
Nectar Recipe
      1 cup of sugar
      4 cups of water

Put ingredients in a saucepan and heat until sugar dissolves. Excess can be stored for a short time in the refrigerator.

Q&A:  Moles - Using Traps and Poisons

QUESTION: Our lawn has been torn up either by moles or gophers, I'm not sure which it is.  How do we rid of them?  Should we spray to kill white grubs, their food?

ANSWER: Moles eat only worms and insects. Earthworms make up the bulk of their diet, not white grubs.  Moles do not have the teeth to eat plant roots, while gophers eat plant roots with enthusiasm. Moles produce superficial tunnels; gophers have deep hidden tunnels. If you see tunnels, you have moles. 

Moles occasionally produce small mounds. Gophers make many mounds, typically over a foot wide and horseshoe shaped. Moles are territorial, with usually only two to three per acre, while there may be 20 or more gophers per acre.  

Superficial mole tunnels are of two types. There are feeding tunnels which, although prominent, may be used only once. Other tunnels are for traveling. Tunnels next to hard structures, such as walks, driveways and garden edging are more likely to be frequently used traveling tunnels. The importance of this information is apparent when you attempt to eliminate them.

Numerous products are sold and suggestions made to get rid of moles -- most of these are not science-based and are ineffective. There is one scientific report of a castor oil-based repellent having a temporary benefit, but the mainstay of control should be either traps or one of the poison gel worms.

A common conclusion among many homeowners is that the traps and worms don't work -- but they do.  In fact, they work well if used properly.  The key step for success is to identify an active tunnel.  To do this you should compress a tunnel segment, mark the spot, and inspect regularly.  Tunnels will be re-expanded if active, and this is where traps or worms should be placed.

Traps come in three varieties -- scissor, harpoon or loop traps. These are listed in order of effectiveness, scissors being most effective.  Garden centers usually sell the harpoon traps, the others are available online.  When using any trap, instructions must be followed completely.

After setting the trap, all light and air currents must be excluded by either using loose dirt filled around the trap or covering with a bucket.  If not successful in two to three days, move it to another site.

The scissor and loop traps retrieve the dead moles, while the harpoon trap may not retrieve the mole. The absence of a dead body may lead to a conclusion of failure with this trap.

Poison gel worms are a new addition to mole control.  Professional turf grass managers report them to be successful, but scientific studies are not available.  Two of the products available are Talpirid and TomCat.  They come with important instructions which must be followed.  The poison should not be used around pets or children.  And, like traps, they are not effective unless placed in an active tunnel, excluding all light.  Lack of mole activity will indicate success. 

For additional information on mole control, please contact the OSU Extension Office at 918-746-3701.