March 2016 / Volume 108    

In This Issue

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

45 - 50 degrees 


Rainfall total last 30 days:  

0.93 inches



2016 Rainfall total: 

1.44 inches




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

Memorial Donations for Sally Sitler:

Ann Humes
Joe Dutton
Kay Morrison
Beverly Couch
Mary Ann Kingdom (non MG)


Estella Franken
Johnathan Lawrence (non MG from Florida)
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.
March Garden, Lawn, & Landscape Tips

  • Cultivate annual flower and vegetable planting beds to destroy winter weeds.
  • Apply mulch to control weeds in beds. Landscape fabric barrier can reduce the amount of mulch but can dry out and prevent water penetration. Thus, organic litter makes the best mulch.
  • Prune roses just before growth starts and begin a regular disease spray program as the foliage appears on susceptible varieties. (HLA-6403 & EPP-7607).
  • Avoid excessive walking and working in the garden when foliage and soils are wet.
  • Start warm-season vegetable transplants indoors
  • Divide and replant overcrowded, summer and fall blooming perennials. Mow or cut back old liriope and other ornamental grasses before new growth begins.

  • Your cool-season vegetables like broccoli, cabbage, carrot, lettuce, onion, peas, spinach, turnips etc. should be planted by the middle of March.

  • Watch for cutworms that girdle newly planted vegetables during the first few weeks of establishment.  Cabbage looper and cabbageworm insects should be monitored and controlled in the garden (EPP-7313).
  • Continue to plant strawberries, asparagus, and other small fruit crops this month.
  • Start your routine fruit tree spray schedule prior to bud break. (EPP-7319).
  • Remove winter mulch from strawberries in early March (HLA-6214). 


  • Remove excessive thatch from warm-season lawns. Dethatching, if necessary, should precede crabgrass control treatment. (HLA-6604)
  • Broadleaf weeds can easily be controlled in cool-season lawns at this time with post-emergent broadleaf herbicides.
  • Pre-emergent crabgrass control chemicals can still be applied to cool-and warm-season turfgrasses. Heed label cautions when using any weed killers near or in the root zone of desirable plantings.
  • March is the second best time of the year to seed cool-season turfgrass; however, fall is the best time to plant. (HLA-6419)
  • Cool-season lawns such as bluegrass, fescue, and ryegrass may be fertilized now with the first application of the season. Usually, four applications of fertilizer are required per year, in March, May, October, and November. (HLA-6420)
  • Begin mowing cool-season grasses at 1 to 3 inches high. (HLA-6420)

  • Prune spring flowering plants, if needed, immediately following their bloom period.
  • Plant evergreen shrubs, balled and burlapped, and bare root trees and shrubs.
  • Anthracnose control on sycamore, maple, and oak should begin at bud swell. (EPP-7634).
  • Diplodia Pine Tip blight control on pines begins at bud swell.
  • Chemical and physical control of galls (swellings) on stems of trees should begin now. (EPP-7168 & EPP-7306)
  • Dormant oil can still be applied to control mites, galls, overwintering aphids, etc. (EPP-7306)  
  • The first generation of Nantucket Pine Tip Moth appears at this time. Begin pesticide applications in late March. (EPP-7306)
  • Control Eastern tent caterpillars as soon as the critters appear.

Tulsa Master Gardener Program of the Month

Home Builders Association Home & Garden Show

Wondering how to survive another week of winter cabin fever?  Tulsa Master Gardeners are coming to your rescue. Months of planning and preparation come together for a short week in mid-March for the HBA Home and Garden Show.  March 10th through the 13th, MGs will showcase a variety of gardening ideas and research-based information which will help to motivate our visitors to create their own green space.
During the show, thousands of visitors will flock to our 5,000 square-foot center space in 'The Gardens' (lower level of the River Spirit Center on Tulsa's Fairgrounds) to learn gardening techniques and stroll through a multitude of creative pocket gardens.  There is surely something for the adults to appreciate and for the kids to enjoy.  Enjoy the serenity of a Zen space, a quiet quaint cottage garden, and small water garden.  Kick it up a notch in the urban patio and garden party pockets.  Oklahoma Proven, Xeri-scape, prairie, and native wildlife plantings will be displayed.  Experience the gorgeous insect displays, pollinator pockets, as well as making a nature craft with your children.  Many Master Gardeners will be on hand to greet visitors and assist with gardening questions.
For more information on the show please visit the Tulsa Home Builders Association website:


Master Gardeners Spring Plant Sale
Pre-Order For Best Selection
Wednesday, April 13th from 4 - 7 p.m.
Thursday, April 14th, from 9 am to 7 pm
Tulsa County Fairgrounds, Central Park Hall, Gate 12
With another relatively warm winter mostly behind us and wide swings in moisture levels, selecting the right plants for your spring and summer garden is very important.  Our plant sale website has a list of heat and drought tolerant plants which produce vibrant color that doesn't wear out over the summer. Such plants as Mexican heather (cuphea), the profusion series zinnias and salvia mystic spires can produce flowers all summer to attract bees and butterflies. Pre-order now and these plants will be ready to go in your flower beds on April 14th.  When you are picking up your pre-ordered plants, you will also find a wide selection of native plants, herbs, veggies, annuals and more to add variety to your garden.  Abundant varieties of this year's Herb of the Year, the chili pepper, will be featured with recipe suggestions. Master Gardeners will be available to answer questions and help you choose plants that will work in your garden.  Proceeds from the Spring Plant Sale support the many Tulsa County Master Gardener programs that are provided free in our community.

Plants may be purchased two ways: 
  • Pre-order Form: NOW is the time to order great bedding plants, perennials, herbs, ornamental grasses and accent plants. This year you can order and  through Friday, April 1. You can also PRINT THIS FORM to fill out, or you can pick up a paper order form at the OSU Extension center. The paper forms must be received (by mail or in person) with payment at the Tulsa County Master Gardener office (4116 East 15th St, Tulsa, OK 74112-6198) by 4:00 pm, Friday, April 1.  As a special offer this year, for all pre-orders that exceed $100, you will receive a $7 coupon to be spent on plants offered at the Plant Event on April 13th and 14th.  IMPORTANT!  Plants must be picked up at Tulsa County Fairgrounds, Central Park Hall between 4:00 pm and 7:00 pm on Wednesday, April 13th or between 9 a.m. and 7 p.m. on Thursday, April 14th.   
  • Plant Sale on April 13th and 14th: Didn't pre-order? No problem! You will find a wide variety of plants especially selected just for this Plant Event, including natives, proven winners and other hard to find plants. These plants are sold on a first-come, first-served basis. The sale is open to everyone on April 13th from 4:00 to 7:00 pm and April 14th from 9:00 am to 7:00 pm. SHOP EARLY, DON'T MISS THIS! 
To order and pay online or to print a form on your computer and to view pictures and additional information about the plants available on the Spring Plant Sale order form, CLICK HERE.

Thank you for supporting the Tulsa County Master Gardener Program!
ebruary means the Academy Awards are approaching and cold weather has us firmly in her grip.  Now is the time to create your own two act drama in the yard!


2016 Oklahoma Proven Plants

When you hear the term "Oklahoma Proven", you can rest assured that you're purchasing or maintaining a plant that has demonstrated durability and stamina across the entire state of Oklahoma.   The Oklahoma Proven program is coordinated by faculty in the Department of Horticulture and Landscape Architecture at Oklahoma State University.  The plants that make this list span a variety of trees, shrubs, annuals and perennials that can take a lickin' and keep on tickin'.
This year, the list includes five offerings and, at least one of them, The Collector's Choice; Magnolia, deciduous cultivar is already in full bloom. This variety comes in a wide variety of colors, including red, pink, white and purple.  An older variety called "Elizabeth" has  beautiful yellow flowers.  "Butterflies" is a newer selection with deeper yellow blooms.  Magnolias love full sun to part shade and prefers moist, well-drained, acidic soil and has a hardiness of zones 4-9.

The 2016 tree is the beautiful Escaparment Live Oak, a smaller version of the coastal live oak.  This tree has a slow growth habit but can reach up to 40 feet high with a canopy just as wide.  The Escarpment live oak is native to southern Oklahoma and all the way to central Texas and northern Mexico.  In other words, it's more drought tolerant than the coastal live oak.  It makes a perfect shade tree for smaller urban landscapes.  I0t's long-lived and provides an excellent nesting site for birds.  This tree has elongated acorns that are enjoyed by wildlife.  The Escarpment likes full sun or light shade and prefers a well-drained soil that is alkaline to slightly acid.  It is hardy from zones 6-10.

The Color Guard Yucca also made the list with its virtually stemless evergreen mounding form. It's an evergreen shrub that has an upright growth habit with sword shaped leaves.  Its blooms are prevalent in late spring and display a bell shaped design. This plant is great as a border or container plant.  For people looking to design a xeriscape or low maintenance garden, the Yucca is a winner.  This fragrant plant deserves full sun to part shade.  Keep the soil dry to medium and always well-drained.  It can withstand zones 3-8.

The 2016 perennial for 2016 is the Carex Sedges which has grass-like stems and short flowers.  There's a range of colors from green to golden, blue, and a variegated variety, to name a few.  Most often, you'll see Sedges grown in small groups or masses.  They look beautiful as borders and grow well in shady areas where the variegated variety really pops.  There are some Sedges that require damp and even wet environments while others thrive in moderately drought conditions.  Sedges love full sun to shade with dry to wet soil and have a hardiness from zones 3-10.

Lastly, but most certainly not least, is Vinca, the annual for 2016. Also known as the periwinkle, this beautiful specimen can take the heat that is delivered in Oklahoma as well as the humidity of the southeast.  It needs full sun and warm temperature if it's going to thrive.  The blooms come in a variety of colors including red, white, purple and pink.  You can expect this striking flower to grow up to 12 inches tall and spread up to 24 inches wide based on the cultivar.  This plant is disease resistant, which makes it perfect for our zone.  It likes full sun to part shade and well-drained, slightly dry soil.  In terms of its hardiness, use this plant as an annual. 


Drip Irrigation - Part 2: Installation & Maintenance
(Part 1 - Planning was last month)

In the February newsletter, Part 1 (Design and Planning) of a Drip Irrigation System was featured.  If you did not get a chance to read it, please take a few minutes to review first before reading Part 2.

It's now time to put that plan into action to decrease your summer work.  A simple home garden irrigation design is inexpensive and relatively easy to install.  Water is measured in gallons per hour (GPH).  The zones in a drip system enable you to deliver the amount of water needed to a specific area for a specific time, providing optimum moisture to the plants.  Each zone will require a timer (if using), a back-flow prevention device, a filter, a pressure regulator, and a hose adapter.  

From the hose adapter, other components easily snap together.
At the main water source, connect controller (manual or automatic).  Route a " poly-tubing distribution line from the main water source to the area to be watered for each zone.  Snap the distribution line into the adapter at the water source.  Secure the distribution line with ground stakes to keep them from moving.  Once the distribution line is in place, " feeder lines snap onto barbed fittings that pierce into the main distribution line.  A variety of fittings enable you to route feeder branches to individual plants or pots.  Continuous emitter lines also snap onto barbed fittings and snake through denser plantings.  Emitters snap into the end of feeder lines and are chosen for the specific plant or area to be watered.  They generally deliver between 0.5 and 2 GPH each.  
Leave the end of the distribution line open so that you can flush out debris from the line once you have completed installation.  Once the system is flushed, close off the end of the tubing.  Cover exposed tubing with mulch if/as desired.

The system should be monitored regularly.  Lines break, inadvertently get cut, pull away from the fittings and emitters, or plug.  Listen and look for leaks.  Check your plants for signs of too little or too much water.  Basic repairs include repairing leaks and either unclogging or replacing clogged emitters.  Filters need to be cleaned each year if using city water, but more frequently if using well or pond water.  Have a tool kit assembled such as a tackle box, which includes cutting pliers, regular pliers, hole punch for " poly tubing, scissors, feeder tubing, assortment of connectors, selection of emitters and goof plugs.  Having a selection of maintenance supplies available in one location makes the repair job relatively quick and easy.  At the end of the growing season, flush the system and drain and winterize the system, which includes storing the controller to prevent freezing.

As your garden grows and changes, you will need to change your drip system accordingly.  With inexpensive tubing and a selection of emitters, it is a relatively simple task to update your system to meet your garden's needs.  With your new drip irrigation system in place, you will likely have a lower water bill and definitely more time to enjoy the garden.  Happy growing!

Additional Resources:
OSU Fact Sheet BAE-1511
        U of California  #21579
        U of Maine  Bulletin #2160


Container Gardening:
Lots of Choices, Lots of Benefits

With changing lifestyles, the popularity of container gardening for vegetables and herbs has exploded.  And, with the creative ideas of gardeners, more options are available to us than ever.  Condo or apartment dwellers as well as gardeners in their seasoned years now all have the opportunity to grow fresh homegrown edibles without some of the problems associated with traditional gardens. In addition, those of us that don't have the right amount of direct sunlight in our yards benefit from container gardening.  A minimum of 6-8 hours is a necessity.  Containers can be just about anything that flowering plants grow in:
  • Flower pots
  • Rolling wooden deep carts
  • Window boxes
  • Five gallon buckets (with holes drilled) from the hardware store
  • Something you have around your house, such as a toy bin or basket, as long as it is large enough and has good drainage
  • Straw bales (not hay!)
  • Get creative!  Look around and see what would be an interesting addition to your patio
Some Cautions:

Be sure to be mindful of the weight of the containers.  Perlite can be added to lighten up the weight of the potting soil.  Garden soil is not recommended for container gardening as weeds and other inert matter may be a problem.  Dark pot colors should also be avoided, as they will heat up quickly in our hot Oklahoma sun.  Larger containers will retain more moisture, so anything less than 12" in diameter is not recommended.  Drainage is essential.  Several small holes or a few large holes are necessary in whichever container is selected.  Pot feet help with good drainage as well.

The advantages are numerous:
  • No weeding and very little soil disease
  • No mulching
  • Transportable when bad weather threatens (move into your garage, under an eve, or throw a sheet over them)
  • If too much or too little sun, move to a new spot
Watering and Fertilizing

Try to locate your containers where water is readily available.  Often, containers will require daily watering in the hot summer sun, so make it easy on yourself, if possible.  Fertilize occasionally, as nutrients leach out of the soil.  A good, balanced organic fertilizer should give you the desired result.  Be sure to always read the directions for each type.

Vegetables and Fruit that do well in containers: 
  • Beans
  • Beets
  • Carrots (provided the container is deep enough)
  • Cucumbers
  • Eggplant
  • Herbs of all types
  • Lettuce
  • Okra
  • Onions
  • Peppers
  • Potatoes
  • Spinach
  • Squash
  • Tomatoes
The wonderful thing about container gardening is that it opens up an opportunity for more of us to have fresh, delicious home grown vegetables at our fingertips.  Explore and enjoy!


Beware: Toxic Plants in the Landscape
While plants and flowers are beautiful additions to our gardens and landscapes, there is also a "dark" side to some of our "pretties". Most articles found in this newsletter are positive and uplifting, as they should be.  But, once in a while, it seems prudent and balanced to also point out some of the dangers that our plants, both outdoors and indoors, can be.  While most adults would know better than to put plants in our mouths, we are reminded that many homes contain small children, pets, or both, who may not have ample knowledge of the dangers that are related to toxic-containing plants.

A "toxin" is a poisonous substance produced by a plant or animal.  Literally, hundreds of species of plants have been on the list of toxic plant materials.  The book Poisonous Plants in the United States and Canada contains this quote "Each year additional species of plants are discovered to be toxic. The absence of a plant from this book does not necessarily imply that it is harmless."  Maybe the author issued that caveat at the direction of his attorney, but it should be taken seriously.  As an example, Western Whorled Milkweed grows in northeastern Oklahoma and as little as 1 kg of its green plant material may kill an adult horse.  Water hemlock also grows in northeastern Oklahoma and its clinical signs and pathology as described in Poisonous Plants tends to get ones attention: "The predominant indication is tremors accompanied by excess salivation, chomping of the jaws and grinding of the teeth eventually progressing to spasmodic-paddling convulsions.  This is due to a combination of involuntary muscular activity and the fight against asphyxiation, the eventual cause of death.  Death may occur within an hour of ingestion or up to eight hours later."
A list of "flower garden plants" that are commonly poisonous include Larkspur, Autumn Crocus, Lily-of-the-valley, Iris, Foxglove, and Bleeding Heart.  Rhubarb a commonly grown vegetable garden plant can be fatal: "large amounts of raw or cooked leaves can cause convulsions, coma, followed rapidly by death" according to the  Area Safety Council and the Oklahoma Poison Control Center.  Ornamental plants on the list include Wisteria, Laurels, Rhododendron, Azaleas, Lantana and many Yews.  Woodland plants on the poisonous list include Jack-in-the-Pulpit, Moonseed, and Mayapple (which contains at least 16 active toxic principles, primarily in the roots).  Jack-in-the-pulpit and its cousin, Dieffenbachia, aren't poisonous but contain sharp crystals of oxalate of lime and, if a stem is chewed, it causes swelling of the tongue with intense pain and "speech may be impossible for several days."  Other "field plants" that are poisonous include Buttercups, Hemlock, Nightshade and Jimson Weed.  Jimson Weed is a form of Datura which is increasingly planted as an ornamental plant in Tulsa (also known at Thornapple).  Poison Hemlock is a wild weed found in Oklahoma: "...all parts of the plant are poisonous and humans have been poisoned by mistaking the plant for parsley".
Some poisonous house plants include Hyacinth, Narcissus, Daffodil, Oleander, Castor Bean, and Mistletoe.  Of course, Mistletoe is the Oklahoma State Flower but eating its berries can prove fatal: "...both children and adults have died from eating its berries".
So, please be aware of some of the dangers that may be lurking around your home and gardens.  Additional suggested readings from the OSU Master Gardener Extension Office Library include:
  • Weeds of the West, the Western Society of Weed Science, 2001
  • Rodale's Illustrated Encyclopedia of Herbs, Rodale Press, 1998 (includes a lengthy list of dangerous herbs)
  • 10,000 Garden Questions, Wings Books, Random House, 1982
  • Toxic Plants of Oklahoma, Cooperative Extension Service, Oklahoma State University
  • Poisonous Plants of the United States and Canada, Prentice-Hall, Inc., 1964

Q&A: When is the best time to prune my roses? 
pruning roses
Answer: It can be tempting at the first sign of sunny days and warmer temperatures to get out in the garden and get to work, but it's important to leave certain maintenance and chores until the fear of a late season frost has passed, especially pruning of roses. In Oklahoma, a general rule of thumb is March 15. Pruning too early can leave tender new shoots susceptible to frost damage.

While waiting to prune, it's always a good idea to amend your soil and, if it's been awhile, to have your soil tested. Roses prefer a slightly acidic soil, and a test is the best indicator of your current conditions. In addition, roses require excellent drainage. You want to provide a soil that retains moisture but still drains well. A 3-4 inch layer of organic matter worked into the soil to a depth of about 8-10 inches is recommended, especially if you are dealing with heavy clay.

When the time comes and you are ready to begin pruning, consider what you want to accomplish with your cuts. The purpose of pruning is to maintain plant shape, remove dead and diseased canes and, if possible, to encourage more abundant or larger blooms. It's also important to understand your particular roses' growing patterns and bloom time when deciding how much wood you want to remove.

First to go should be any dead or diseased wood, also any old canes that are no longer flowering well. You should also take out canes that rub against one another or cross over through the center of the plant, keeping the center open allows for better air circulation that will cut down on disease and fungus growth.

Once these canes are removed, consider the intended shape or growth pattern of the plant and whether your rose variety blooms on new wood or old. If you have a rose that blooms on old wood, pruning too heavily could remove many of your buds. Roses that bloom on new growth can be pruned much harder and will actually encourage vigorous growth and showier blooms.

For additional rose care information and more specific pruning information OSU offers an excellent fact sheet "Roses in Oklahoma" (HLA-6403) available in the Master Gardener Office or online at

Q&A: From time to time, I see information about "Hardiness Zones (HZ)".  What are they and how do they apply to my garden and landscape?

Answer: Over the next several months, gardeners will be buying new perennial plants for their gardens and they should be aware of which perennials will survive over the years in their "Hardiness Zone".
Hardiness Zones are areas across the United States that have been established by the United States Department of Agriculture (USDA). The areas within these lines show the average "coldest"  temperatures during the year.  The areas are set up horizontally from East to West, with designations running from Zone #1 (Northern) to Zone #11 (Southern).  The lower the "Zone"  number, the colder the average temperature for the year.  There is a 10 degree differential between each of the zone numbers.  If a Zone is listed as a "b", the temperature is only 5 degrees differential.

Currently, Zone #1 (along the U.S. and Canadian border) means the last frost is in Mid -June and the first frost is in Mid July.  Tulsa and Northeastern Oklahoma areas are considered to be in Zones 6b-7. This Zone is shown to have its last frost in Mid-April and its first frost in Mid-October, with low temperatures to be between 0 and -5 degrees during the winter months.  It should be remembered that these figures are averages and do not represent what the extreme temperatures might become in one or more years.  Over the last 10 to 15 years, the Tulsa area and Eastern Oklahoma areas have changed from Zone 6 to Zone 7.  This increased warmth has enabled those in the nursery business to stock different types of plants and enable the gardener to enjoy these many plant variations.
When selecting new perennial plants, make sure they have the Hardiness Zones listed.  On most plants sold today, the Hardiness Zones (HZ) are listed on the containers or tags.  But, if not, you need to check with the seller about the plant's HZ rating.
For more information on Hardiness Zones, go to MG web site  In the upper right you will see  "SEARCH".  Click on it and in the "Search For"  box, type in "Hardiness Zones.  Then make your selections of maps.