April 2015 / Volume 97       

In This Issue

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

66 degrees 


Rainfall total last 30 days:  

4.15 inches


Donations Keep Tulsa Master Gardener Program Strong
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, M-F 
Visit us at 4116 E. 15th Street, Gate 6 at the Fairgrounds

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

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.

April Lawn & Garden Tips
  • Wait a little longer for it to warm up before planting cucurbit crops and okra.
  • Plant vegetable crops in successive plantings to ensure a steady supply of produce rather than harvesting all at once.
  • Cover cucurbit crops with a floating row cover to keep out insect pests. Remove during bloom time.
  • Watch for cutworm damage and add flea beetle scouting to your list of activities in the vegetable garden.
  • Warm-season grass lawns can be established beginning late April from sprigs, plugs or sod. (HLA-6419)
  • Fertilizer programs can begin for warm-season grasses in April. The following recommendations are to achieve optimum performance and appearance of commonly grown species in Oklahoma:

Zoysiagrass: 3 lbs N/1,000 sq. ft.     

Bahiagrass: 3 lbs N/1,000 sq. ft.

Buffalograss: 2 - 3 lbs N/1,000 sq. ft.

Buffalograss/grama mixes: 3 lbs N/1,000 sq. ft.

Bermudagrass: 4-6 lbs N/1,000 sq. ft.

Centipedegrass: 2 lbs N/1,000 sq. ft.

St. Augustinegrass: 3-6 lbs N/1,000 sq. ft. 

  • When using quick release forms of fertilizer, use 1 pound of actual nitrogen per 1,000 sq. ft. per application; water in nitrate fertilizers. (HLA-6420)
  • Mowing of warm-season lawns can begin now (HLA-6420). Cutting height for bermudagrass and zoysiagrass should be 1 to 1 inches high, and buffalograss 1 to 3 inches high.
  • Damage from Spring Dead Spot Disease (SDS) becomes visible in bermudagrass (EPP-7665). Perform practices that promote grass recovery. Do not spray fungicides at this time for SDS control.
  • Grub damage can be visible in lawns at this time. Check for the presence of grubs before ever applying any insecticide treatments. Apply appropriate soil insecticide if white grubs are a problem (EPP-7306). Water product into soil.
  • Proper watering of newly planted trees and shrubs often means the difference between success and replacement.

  • Remove any winter-damaged branches or plants that have not begun to grow. Prune spring flowering plants as soon as they are finished blooming. (HLA-6404, HLA-6409)

  • Control of powdery mildew disease can be done with early detection and regular treatment. Many new plant cultivars are resistant. (EPP-7617)

  • Leaf spot diseases can cause premature death of foliage and reduce plant vigor.

  • Most bedding plants, summer flowering bulbs, and annual flower seeds can be planted after danger of frost. This happens around mid-April in most of Oklahoma. Hold off mulching these crops until spring rains subside and soil temperatures warm up. Warm-season annuals should not be planted until soil temperatures are in the low 60s.

  • Harden off transplants outside in partial protection from sun and wind prior to planting.

  • Let spring flowering bulb foliage remain as long as possible before removing it.

  • Hummingbirds arrive in Oklahoma in early April.  Get your bird feeders ready using 1 part sugar to 4 parts water.  Do not use red food coloring.

  • Keep the bird feeder filled during the summer to entice bird varieties which, in turn, help control insects at the same time.

  • Lace bugs, aphids, spider mites, bagworms, etc. can start popping up in the landscape and garden later this month.  Keep a close eye on all plants and use mechanical, cultural, and biological control options first.

  • Be alert for both insect pests and predators. Some pests can be hand picked without using a pesticide. Do not spray if predators such as lady beetles are present. Spray only when there are too few predators to be effective.

  • Schedule a group tour of The Botanic Garden at OSU between the first of May and late October!

Spring Plant Pick-up and One Day Sale!     
Thank you to everyone who made this year's sale another big success. We appreciate your support!

Even if you did not preorder, on April 16 you can shop our retail selection of plants that are hand-picked for just this one day! Selections of native plants, proven winners, Oklahoma proven, and unique choices for your garden and containers are available. Come early for the best selection.
Master Gardeners will also be on hand to answer your gardening questions!

Your plants MUST be picked up on Thursday, April 16 between 9 am and 7 pm at Central Park Hall, Tulsa Fairgrounds, Gate 12. We do not ship or hold plants. Plants not picked up will be considered donations to the Master Gardener program. 

Companion Planting, A Historical Practice  

Companion Planting is a gardening term that has gained popularity in recent years but it is actually a historic practice utilized by Native Americans in the "Three Sisters" planting system. Most people have heard of this concept where corn provides the pole for beans, beans fix nitrogen, and squash provides a living mulch for the other two.


In more modern gardening, companion planting can be any planting of "two or more plant species in close proximity so that some cultural benefit is derived." It is based primarily on historical observation and practice. However, with science taking a greater interest, the term companion planting has become more definitively named "intercropping."


The practice of companion planting can be beneficial in several ways. Trap cropping a "sacrifice" plant can divert pests away from the desired plants. Nitrogen fixation-plants, specifically legumes, fix atmospheric nitrogen in the soil where they and other plants are being grown. Still other plants can exude chemicals from roots or aerial parts that suppress or repel pests. Nurse cropping with tall, sun-loving plants can provide a canopy for low, shade-tolerant plants. Finally, a number of plants attract beneficial insects that prey on pests and/or attract pollinators.


So, is companion planting/intercropping a sound gardening practice? The "Three Sisters" technique has historical evidence to support the positive benefits of the practice. You should always bear in mind, if attempting any gardening technique, when environmental requirements (i.e. sun, soil, and water) of our plants are met they will grow strong and healthy. If utilizing the companion planting/intercropping technique, as with anything in your garden, first identify the problem and explore all possible solutions before taking any action.


Since tomatoes are the ever popular warm season vegetable of choice here in Oklahoma, here are some companions that may prove beneficial: asparagus, basil, beans, borage, carrots, celery, chives, collards, cucumber, garlic, lettuce, mint, nasturtium, onion, parsley, and peppers. On the flip-side, there are "antagonists" that are not suited to be in proximity to tomatoes, such as corn and potatoes.  For more information on companion planting, refer to OSU's fact sheet (HLA-6431).  There are many other companion plantings that may be beneficial...however, bear in mind, no scientific evidence could be found to support the benefits of the listed companions. 

2015 Oklahoma Proven Plants    
The Oklahoman gardener is faced annually with the challenge of outwitting our diverse growing conditions. Our friends at the Oklahoma State University Cooperative Extension started the Oklahoma Proven Plant Selection program in 1999 just for this reason - to help us select trees, shrubs, and flowers that will have a high probability of thriving in your garden. We are pleased to share the 2015 winners with you below!


null TREE Collector's Choice for 2015:   

Black Gum (Nyssa sylvatica)

Growth Size: 50' - 60' tall, 25' wide

Growing Velocity:  Slow

Exposure:  Full sun to part shade.

Soil:  Prefers moist, well-drained, acid soil, but is adaptable.

Hardiness:  USDA Zone 4-9

Attributes: Excellent form, more resistant to leaf spot.

Appearance:  New growth is red, matures to shiny dark green, brilliant red in fall.

Eco Benefits: Small flowers and black fruits attract bees, birds, and other pollinators

Varieties: Fire Master (Nyssa sylvatica 'PRP1', Red Rage (N. sylvatica 'Hayman Red')


TREE for 2015:  Hedge Maple (Acer campestre)

Growth Size: 25' - 35' tall and wide

Growing Velocity:  Slow

Exposure:  Full sun to light shade.

Soil:  Tolerates a wide variety, but prefers rich, well-drained. Grows well in compacted and alkaline soils.

Hardiness:  USDA  Zone 5-8

Attributes: Excellent  form, tolerates severe pruning, can be used as hedge. One of the tougher maples.

Appearance:  Green foliage in summer, yellow-green to yellow in fall.

Eco Benefits: Branches develop low to ground, providing cover for wildlife. Can be limbed up if you prefer

Varieties: Golden and variegated leaf forms available.


SHRUB for 2015 :  Barberry (Columnar Forms)

Growth Size: 3' - 5' tall and 2' wide

Growing Velocity:  Moderate

Exposure:  Sun to part shade.

Soil:  Moist, well-drained but adaptable to wide range of soils. Very drought tolerant once established.

Hardiness:  USDA  Zone 3-8

Pests:  No serious pest problems.

Attributes: Low maintenance. Use as specimen, groupings, borders.

Appearance: Narrow upright plants. Available in foliage colors - golden, red, orange, purple.

Eco Benefits: Little sharp spines making it dog and deer-resistant.

Varieties: Rocket and Pillar series


PERENNIAL for 2015:  Garden Phlox, Volcano Series

Growth Size: 24" - 28" tall

Growing Velocity:  Fast

Exposure:  Sun to part shade.  

Soil:  Prefers moist, well-drained, but adaptable to wide range of soils.  

Hardiness:  USDA  Zone 3-8

Attributes:  Resistant to mildew, blooms June through fall (if you cut back after initial bloom).  Very fragrant.

Appearance: Attractive cluster flowers:  red, pink, white, purple, bicolored.

Pests:  Leaf mildew if too moist or too close together. Doesn't affect blooming.

Eco Benefits:  Bees, butterflies, hummingbirds, and other pollinators love this plant.

Varieties:  Volcano


ANNUAL for 2015:  Spider Flower, Cleome hybrids

Growth Size: 3' - 6'  tall

Growing Velocity:  Fast

Exposure:  Sun to light shade.  

Soil: Moist, well-drained but adaptable to wide range of soils.  

Hardiness:  USDA  Zone 4-10

Attributes:  Blooms all summer. Some varieties re-seed themselves.

Appearance: Attractive cluster flowers; white, pink, lavender, blue. Leaves have palm shape.  

Pests:  No significant pests.

Eco Benefits: Butterflies, hummingbirds

Varieties:  Sparkler series, Spirit series, Senorita Rosalita (pink), Senorita Blanca (white with lavender).  


Visit the Oklahoma Proven website to learn more and see award winning plants for the Oklahoma area from years past. 

Milkweed - A Monarchs Delight!   
One of the keys to having beautiful monarch butterflies around your garden is having lots of milkweed. Monarchs simply cannot survive without milkweed. Because of modern changes, habitat destruction, and shifting land management practices (such as suburbanization), there is a lot less milkweed than there was in the past. This has caused monarch butterfly numbers to be at an all-time low for the last two overwintering seasons, and many pollinators are declining as well. By planting milkweeds - the host plants for monarch caterpillars - and nectar plants for adult monarchs and pollinators, you can help maintain the monarch migration and sustain the pollinators whose services maintain our ecosystems. Losing milkweed is literally a disaster for monarchs since they use milkweed to lay their eggs and the monarch caterpillars can eat nothing but milkweed.

All milkweeds are of the genus Asclepias. They are perennial plants, growing each spring from rootstock and seeds rather than seeds alone. Be aware that sometimes nurseries are afraid to call them milkweeds since people shy away from anything with "weed" in the name and because milkweeds have an undeservedly bad reputation. So, be sure to look for this botanical name. Some of the more popular milkweed varieties in our area are: Butterfly Weed (Asclepias tuberosa), Common Milkweed (Asclepias syriaca), Swamp Milkweed (Asclepias incarnata), and Balloon Plant Milkweed (Asclepias Physocarpa).  

When planting milkweed, be sure to plant multiples, three to five or more. A single plant simply will not be sufficient for monarchs as they are eating machines. If you want lots of monarchs, plants lots of milkweed. Planting milkweed is a great way to help other pollinators too, as they provide valuable nectar resources to a diverse suite of bees and other butterflies. While milkweed is a beautiful plant to look at, be sure to keep milkweed sap out of your eyes as it can be irritating.

A very good resource on Oklahoma butterflies can be found on the Oklahoma Department of Wildlife Conservation website. In addition, a terrific resource to learn a lot more specifically about monarch butterflies as well as milkweed is on the website MonarchWatch.org. It contains a plethora of information, including information about the issue of monarch decline, what can be done to reverse that trend, all kinds of information about monarchs and other butterflies, and lots of information on buying and growing milkweed. So, read up on the monarch, then get out there are start growing milkweed to help re-build the population of monarchs. Your local butterfly and bee pollinators will love you for it!