November-December 2013 / Volume 81           

In This Issue
November Lawn and Garden Tips
Protecting Young Trees from Sunscald
Mulching for Winter Conditions
Drying Herbs for Winter Use
Ask A Master Gardener...Fertilizing Young Trees...Digging Bulbs for Winter

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

59 degrees 


Rainfall total last 30 days:  

2.91 inches


4 Ways to Contact Us
Email us at:

See our website at: 

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 Information?

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.
November Lawn and Garden Tips 


  • Leftover garden seeds can be stored in an airtight container in the refrigerator or freezer until next planting season. Discard seeds over 3 years old.
  • Gather and shred leaves. Add to compost, use as mulch or till into garden plots.
  • Clean and store garden and landscape tools. Coat with a light application of oil to prevent rusting. Drain fuel tanks, irrigation lines, and hoses. Bring hoses indoors. 
  • Fertilize cool-season grasses like fescue with 1 pound nitrogen per 1000 sq. ft.
  • Continue to mow fescue as needed at 2 inches and water during dry conditions.
  • Control broadleaf winter weeds like dandelions.
  • Keep falling leaves off fescue to avoid damage to the foliage.


  • Prune deciduous trees in early part of winter. Prune only for structural and safety purposes.
  • Wrap young, thin-barked trees with a commercial protective material to prevent winter sunscald.
  • Apply dormant oil for scale infested trees and shrubs before temperatures fall below 40 degrees Fahrenheit. Follow label directions.
  • Continue to plant balled and burlapped and containerized trees.
  • Watch for arborvitae aphids, which tolerate cooler temperatures in evergreen shrubs.
  • Tulips can still be successfully planted through the middle of November.
  • Leave foliage on asparagus, mums, and other perennials to help insulate crowns from harsh winter conditions.
  • Bulbs like hyacinth, narcissus and tulip can be potted in containers for indoor forcing.  

Protecting Young Trees from Sunscald 
As we move from warmer days to cooler days coupled with colder nights, trees begin to go into their natural dormancy state. How this happens is interesting. The living cells within the vascular cambium layer (situated between the xylem and phloem layers) stop growing and begin their process towards dormancy which will protect them against winter's freezing conditions. However, with our usual Oklahoma weather where we get alternating cold days/nights with warmer days, this can present a problem.

On a winter's day following a cold night, the sun may come out and warm up part of the tree trunk at a low angle on the side that faces the sun. This is usually the southwest side, where temperatures can be much higher than that of the shaded side of the tree. The living cells that are warmed can actually come out of dormancy and lose their protection from the cold because they are tricked into thinking spring has arrived. Then, a recurrence of freezing temperatures the next night kills the activated cambium layer. This can produce an elongated split in the bark, or sometimes an open wound, which can become an entry point for disease in the next growing season.

Also, water flow from the roots is cut off, because dead cells in the trunk cannot conduct moisture. As a result, much of the tree top dies back, and the tree becomes susceptible to other organisms, such as fungi and insects. Because this issue occurs on the sunny side of the tree in the winter where the sun is in the southwest, it is sometimes called "Southwest injury".

Prevention is fairly simple. You simply need to shade the trunk from the sun during the winter. Nurseries have many tree wrap remedies, including light-colored paper or plastic tree wrap materials. If you happen to have any extra crepe paper or burlap around the house, that can also provide good shade protection. But, do not wrap the trunk with anything binding, such as duct tape as this can kill the tree. Start wrapping at the base of the tree, overlapping one-third with each turn. This ensures the wrap will shed water. Wrap up to just above the second branch and secure with stretchable tape.
Tree wraps should be applied in November and removed at the start of next year's growing season. It is imperative that the wrap be removed in the spring. If left on, it can harbor insects or disease and the tape can injure the tree as it expands in the spring.

This procedure should be done for the first two years of a young trees life. Young, thin-barked trees most susceptible to this injury include the Oklahoma Redbud, fruit trees, linden, birch, ashes, willow, and maple trees, but all trees would welcome this protection.

For more information, please contact visit our website.

Mulching for Winter Conditions   
Plants are now going into dormancy, a type of hibernation, to prepare for the upcoming winter. This protects them from cold damage. Should any new growth of buds occur then, it would be susceptible to freezing injury. The process of developing dormancy depends on the soil cooling as well as lower air temperatures.

During early fall frosts, the air temperature is below freezing but the soil temperature typically is still warm. It takes time for it to cool. Placing mulch onto warm soil may delay cooling and the development of dormancy, potentially allowing new cold sensitive growth to develop. In a perfect world, one would mulch in the fall after frosts occur, but before we have any hard freezes.

As of November 4, most of Tulsa County has remained frost free, but much of the surrounding areas have seen a couple of light frosts...but no hard freezes as of yet. So, there is still some time. Of course, you will not kill plants mulching while the soil is still warm. If you only option is to either mulch before frosts or not mulch at all, mulch before.

Another chore which should go hand-in-hand with mulching is garden cleanup. Sanitation in the fall garden will help prevent the need for insecticides and fungicides during the growing season.

Many summertime diseases over-winter in trash remaining in the garden at season's end. Black spot on roses, leaf spot on red-tipped Photinia are good examples. These leaves are infectious and should be bagged and placed in the trash.

Some pests also survive winter in garden trash. Spider mites, squash bugs, cucumber beetles, cabbage worms, tomato horn worms and slugs commonly use garden debris for winter shelter.

For more information, click for OSU fact sheet No. 6404.

Drying Herbs for Winter Use       
The weather might be getting colder, but there is still some time to gather up what is left of your herbs and preserve them for use over the winter.

Harvest herbs in the early morning when flavor is at its peak. Wash the leaves and stems carefully in cold water and remove any dead spots or insect debris. Shake off any visible moisture, and the herbs will be ready for drying. 

Fresh herbs can be dried in a number of ways. Probably the simplest way is to tie the stems together, forming a bundle, and hang them upside down in a cool dry place. To avoid dust and insects, the bundle can be hung inside a paper bag. Allow a few days to dry completely.

If you have a dehydrator, arrange the herbs on the drying trays and dry at about 115 to 125 degrees until they are brittle and easily crumbled. Drying time will vary, but can range anywhere from one to three hours. 

Finally, the drying process can be accomplished in the oven. Because herbs dry at a temperature setting lower than most ovens will allow, preheat the oven, and then turn it off, allowing it to cool slightly before adding the herbs spread on clean cookie sheets.

Once they are dried sufficiently, store your dried herbs in an airtight container in a cool, dry place. They should remain flavorful for up to twelve months.

Question: It was suggested to me that I dig up my elephant ear and canna bulbs for winter storage. Is this needed?
Answer: For our region, this is a difficult question to answer. Some authorities suggest digging and storing them all, because our winters are too cold. However, there is a conflict between theory and practical gardening experience. Many perennial beds of cannas and elephant ears in Tulsa are several years old.

The world's largest grower of cannas, Horn Canna Farm, is located in Carnegie, southwest of Oklahoma City. The canna experts at Horn suggest most cannas may be safely left in the ground for winter in cold hardiness zone 7 and perhaps zone 6 if the winter is a mild one.

Elephant ear tolerance of cold is more complex. There are several genera of plants that go by the common name "elephant ear." They all have similar structure, but their reported tolerances for cold are widely different. Some are very intolerant of cold and must be stored indoors. However, many of the commonly sold elephant ear bulbs in the genus Colocasia are rated to hardiness zone 7. They usually survive winters with protection.

Hardiness zones refer to the average lowest annual temperature of an area. Tulsa is officially in zone 7a (zero to 5 degrees or warmer). Areas just to the north are in zone 6b (zero to minus 5 degrees) however.

If you have a prized plant and wish to be sure of survival, by all means dig the tuber and store it until spring. However, if you decide to leave tubers in the ground over winter, be aware that both types are more likely to survive the cold if they are on the south side of a structure and wind protected. They must also be heavily mulched and have greater survival if the soil is well drained and on the dry side.

Click here to send your question to the Tulsa Master Gardeners or see Answers to other Questions on the Web site.