June 2014 / Volume 88         

In This Issue
June Lawn and Garden Tips
Summer Flowering Bulbs
Nail Bagworms
Rain is Relief...But How Much?
Ask A Master Gardener...Coneflower Root Rot

Weather Stats for Gardeners

Soil Temperature 2" below sod:   

76 degrees 


Rainfall total last 30 days:  

6.02 inches


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.

June Lawn and Garden Tips     
  • Find someone to water plants in the garden while on vacation. Harvesting vegetables and mowing the lawn are a must and imply that someone is home.   
  • Mulch vegetables, ornamentals, and annuals to reduce soil crusting, and to regulate temperatures and moisture during hot summer months. Mulching will reduce about 70 percent of the summer yard maintenance.
  • Remain alert for insect damage. Add spider mite to the list. Foliage of most plants becomes pale and speckled; juniper foliage turns a pale yellowish color. Shake a branch over white paper and watch for tiny specks that crawl.   
  • Renovate overgrown strawberry beds after the last harvest. Start by setting your lawnmower at its highest setting and mow off the foliage. Next thin crowns 12 to 24 inches apart. Apply recommended fertilizer, preemergence herbicide if needed and keep watered. (HLA-6214).  
  • Fertilize warm-season grasses at 1 lb. Nitrogen per 1,000 square feet. Don't fertilize fescue and other cool-season grasses during the summer.
  • Dollar spot disease of lawns can first become visible in mid-May. Make certain fertilizer applications have been adequate before applying a fungicide. (EPP-7658)
  • Seeding of warm-season grasses should be completed by the end of June (through July for improved varieties such as Riviera and Yukon) to reduce winterkill losses. (HLA-6419)
  • Brown patch disease of cool-season grasses can be a problem. (HLA-6420)
  • White grubs will soon be emerging as adult June Beetles. Watch for high populations that can indicate potential damage from later life cycle stages as grubs in the summer.     
  • Watch for first generation fall webworm. (EPP-7306)
  • Vigorous, unwanted limbs should be removed or shortened on new trees. Watch for forks in the main trunk and remove the least desirable trunk as soon as it is noticed. (HLA-6415)
  • Pine needle disease treatments are needed again in mid-June. (EPP-7618)
  • Remove tree wraps during the summer to avoid potential disease and insect buildup.
  • Softwood cuttings from new growth of many shrubs will root if propagated in a moist shady spot.
  • Protect trees from lawnmowers and weed eaters by mulching or using protective aerated covers.
  • Pinch back leggy annuals to encourage new growth. Fertilize and water appropriately.
  • Feed established mums and other perennials.
  • When picking fresh roses or removing faded ones, cut back to a leaflet facing the outside of the bush to encourage open growth and air circulation.
  • Stake tall perennials before toppling winds arise. 

Easy to Maintain Summer Flowering Bulbs 
Many gardeners love the results from planting bulbs. Most know that spring flowering bulbs must be planted in the previous fall. Given this, then summer flowering bulbs need to be planted in the spring. In other words, if you haven't done so already, plant now. They are generally easy to plant and to maintain, and many types of bulbs already have planting instructions on the packaging somewhere. However, there are a few things to remember to ensure a successful bounty of color from your labor. Ideally, you should plant summer flowering bulbs and tubers near the same time that you set out tomato plants (around April 15th). As we are now heading into summer, your best option may be to find some pre-started plants, or wait until next spring.

Quality bulbs and well-drained soil are the two most important ingredients to a successful summer garden. Summer bulbs require a great deal of water immediately after planting and the soil in your garden should be continually moist. Maintain a pH level between 6 and 7 in order to bring out the true color of the flower bulbs.

Cannas are among the most colorful summer bulbs, as flamboyant as their tropical American ancestry, with ruffled spikes tapering to refined buds. These perennials come in a vast variety of colors and sizes, and boast immense paddle-shaped leaves. Although Cannas are considered tropical and exotic, other than lots of sunshine and fertile, moist soil, you don't have to pamper them. Simply dig a hole 2-3 inches deep and set them where the eye is up. Cover and water thoroughly, then keep a thin layer of mulch around them to help retain soil moisture. Stake as needed and deadhead spent flower to promote continued flowering.  Separate every 3-4 years in the winter to avoid over-crowding. As for pests, slugs, snails, spider mites and caterpillars may be a problem. Disease wise, rust, fungal leaf spot, and bacterial blight are common. Most of this can be avoided by planting in full sun with plenty of air flow around the leaves. Fight these pests and diseases organically or with insecticides just like you do others in your garden.

Many summer flowering bulbs and tubers are well suited for patio containers and should be planted closer together for a full look. Also, a variety of summer bulbs make great cut flowers, but some of the taller varieties may require staking.  
In our planting area (Zone 6-7), many summer flowering bulbs such as Dahlias, Gladiolus and Caladiums will need to be dug up and stored in the fall. Cannas will usually over-winter in the ground with some protection. Just cut them back close to the ground after a hard freeze and maintain a healthy layer of mulch over them. However, if you prefer to store them in the winter, simply lift them out of the ground and replant next spring. Shake off any loose soil and air dry for several days before storing in a cool, dry, well-ventilated location. Do not store in plastic, as plants need to breathe even over the winter.

Following these few tips, you are sure to have a successful and bountiful display of color in your garden for years to come. Plant and enjoy!

Now is the Time to "Nail" Bagworms        
Bob Bauernfeind 

It is now time to "do battle" (I love military metaphors) with that "infamous" of insect pests known as the bagworm (Thyridopteryx ephemeraeformis). Throughout most of the area, bagworm eggs have hatched and the young caterpillars are out-and-about feeding on both broadleaf and evergreen trees and shrubs.

Bagworms were first considered a pest of primarily conifers but over the years they have expanded their host range to
include a number of broadleaf plants including rose, honeylocust, and flowering plum. I have even seen them "eating chicken wire" at the Sunset Zoo (Manhattan, KS). At this time of year, what is the best way to deal with bagworm caterpillars and thus prevent them from causing damage? Hand-picking any small caterpillars (along with their accompanying bag) and placing them into a container of
soapy water will kill them directly.

This is highly therapeutic and, if feasible, will quickly remove populations before they can cause substantial plant damage. You should consider having a weekend "bagworm hand-picking party" with prizes awarded to those individuals that collect the most bags. For those less interested in the pleasures of hand-picking, there are a number of insecticides labeled for use against bagworms including those with the following active ingredients (trade name in parentheses): acephate (Orthene),
Bacillus thuringiensis subsp.kurstaki (Dipel/Thuricide), cyfluthrin (Tempo), lambda-cyhalothrin (Scimitar), trichlorfon (Dylox),indoxacarb (Provaunt), chlorantraniliprole (Acelepryn),
and spinosad (Conserve). Many of these active ingredients are commercially available and sold under different trade names or generic products. However, several insecticides may not be directly available to homeowners. The key to dealing with bagworms when using insecticides is to make applications early and frequently enough in order to kill the highly susceptible young caterpillars that are feeding aggressively on plant foliage. Older caterpillars that develop later in the season, in the bags, may be 3/4-inches long, and are typically more difficult to kill with insecticides. In addition, females tend to feed less as they prepare for reproduction, which reduces their susceptibility to spray applications and any residues.

The bacterium Bacillus thuringiensis subsp.kurstaki is active on young caterpillars; however, the active ingredient must be consumed to be effective, so thorough coverage of all plant parts and frequent applications are required to avoid having to deal with later stages. This compound is sensitive to ultra violet light degradation and rainfall, which reduces any residual activity. Spinosad is the active ingredient in a number of homeowner products (including Borer, Bagworm, Tent Caterpillar & Leafminer Spray; Captain Jack's DeadBug Brew; and Monterey Garden Insect Spray) and works by contact and ingestion (stomach poison); however, it is most effective when ingested and it can be used against older or larger bagworm
caterpillars. Cyfluthrin, lambda-cyhalothrin, trichlorfon, chlorantraniliprole, and indoxacarb may be used against both the young and the older caterpillars. However, thorough coverage of all plant parts, especially the tops of trees and shrubs, where bagworms commonly start feeding, and
frequent applications are required. The reason why multiple applications will be needed when bagworms are first detected is because bagworms "blow in" (called 'ballooning') from neighboring plants. If left unchecked, bagworms can cause significant damage, thus ruining the aesthetic quality of plants. In addition, they may actually kill plants, especially
evergreens since they don't usually produce another flush of growth, and newly transplanted small plants.

If you have any questions regarding the management bagworms contact your county horticultural agent, or university-based or state extension entomologist.

Rain is Relief...But How Much?  

I am sure most everyone has appreciated the recent rainfall we have received in the Tulsa area, especially coming at the end of one of the driest springs in many years. The main impact has been in terms of soil moisture, which has improved significantly since the middle of May. This short-term relief is certainly welcomed, but remember, the rainfall deficit over the long term (last 3-4 years) is still up there among some of the historic droughts of the past, with the Tulsa area now about 35 inches behind the normal rainfall since October 1, 2010.  


So, just how dry was it this spring (March through May) in Tulsa? It ended up as the 19th driest on record, but before the rains at the end of May, we were well on pace to be in the top 10 driest. In any case, we are still way behind in long term rainfall and remain in severe drought in Tulsa county, with extreme drought conditions still lurking not far to our northwest.


Is there any good news on the horizon? Well, maybe. It appears that El Niňo conditions are developing in the Pacific Ocean. And, should this turn out to be a strong one, that upps the odds in favor of above normal precipitation...in the winter months. El Niňo impacts on summer weather are more or less negligible in this part of the world. This will come better into focus as we move through what I hope turns out to be the coldest and wettest summer on record...I can dream can't I?

Question: Following all the recent rain, my coneflower wilted. I dug it up and most of the roots were gone. Was this due to the wet soil?

Answer: Yes. It is called root rot and is a common problem related to our recent heavy rains. A number of soil fungi can infect and destroy roots if the conditions are favorable. Excess water coupled with poor drainage, especially in soil with high clay content, forces oxygen out of the soil. This is a perfect environment for a root fungus to thrive. Root rot is not limited to outdoor plants; it is also very common in houseplants that are overwatered, poorly drained and receives too little light.

Plants with root rot initially develop yellowness of leaves, have stunted growth, wilt and eventually die. When the roots are examined, they are brown, mushy and stinky, rather than firm and whitish cream-colored as normal. It is difficult to salvage an infected plant, and it probably should be discarded, although a prized plant might be saved by rooting a cutting.

The best approach is prevention; fungicide chemicals are not practical. Try to avoid plants susceptible to root fungus in moisture-prone areas. It is also helpful to delay mulching wet garden beds until they are dried to a reasonable level.

Garden beds with high-clay soils benefit from added organic material, but the best strategy for poorly drained heavy clay is to use above-ground planting beds. Try planting shrubs, annuals and perennials in mounds of a mixture of good soil and compost or shredded bark. Keeping their roots above soil level will allow good drainage and prevent root rot.

Avoid problems in houseplants by always using fast-draining sterile potting soil. Garden soil should not be used; it drains poorly and may contain disease organisms. Watering house plants thoroughly only when needed and removing drainage water will help prevent root disease.

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