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September, 2010                                                     Number 42 
"A garden is never so good as it will be next year." - Thomas Cooper

Soil temperature on August 29: 79 degrees                               Rainfall past 30 days: 1.13 inches


Ask a Master Gardener

Question: I still have several bagworms hanging on our junipers. The "bags" appear to be empty. Should I do anything?

Answer: Bagworm caterpillars make a distinctive spindle-shaped bag and attach it to twigs on a variety of trees and shrubs. They prefer junipers, arborvitae, spruce, pine and cedars but may be found on deciduous trees. In the fall, male caterpillars find the bags of females and mate. The females may lay up to 300 eggs in the bags and then die. Eggs overwinter in the "empty" bags and hatch to emerge as caterpillars in late May to mid-June. It is important to remove all bags before the eggs hatch. Repeated infestations can weaken trees. Pick the bags off the trees by hand and place in a sealed plastic bag for proper disposal. Click here for more information.

Question: I regularly water the Colorado Blue Spruce in my front yard, but it continues to look brown on some parts. What else can I do to save this tree?
Answer: Picea pungens, Colorado (Blue) Spruce, is native to the intermountain states of the west. It is cold hardy to zone 2, which means it does not like the Oklahoma heat! Its root system is shallow and wide. When the heat index surpasses 100 degrees, this tree suffers much stress. The best relief for the Blue Spruce is cool night temperatures so the root system can recover. This does not change the fact that it is not native. To sustain this tree in Oklahoma, weekly deep soakings are imperative. Using a small sprinkler turned up enough to spray two to three inches high and placed at the base of the tree for an hour is appropriate. This is also true for large deciduous and evergreen trees during conditions of drought and high temperatures.  Cover the shallow roots with two to three inches of mulch to retain moisture and to help moderate soil temperatures. Do not apply fertilizers or root stimulators when trees are stressed. These trees benefit from protection from afternoon heat and direct sunlight. Continue to check soil moisture until the heat subsides.

Question: I planted my first passion vine and some red worms are devouring the leaves! How can I kill them?
Answer: The Passiflora, commonly called passion vine, is a vigorous vine native to parts of Oklahoma. It is admired for its exotic purple flowers. It is also the host or food plant for the caterpillar of the Gulf Fritillary butterfly (Agraulis vanillae). It is in the butterfly category of brushfoots, which also includes the Monarch. The brushfoots are always orange and brown with white spots, in some combination. The two front legs are usually pulled up. The larval stage is a reddish caterpillar with black spines. These caterpillars selectively consume leaves on the passion vine but will not harm the vigor of the plant.
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The caterpillars can be picked off, eaten by birds or allowed to turn into the chrysalis stage from which a beautiful butterfly will emerge.

Eight Lawn and Garden Tips for September
  • Apply pre-emergent herbicides before Sept. 15 to control winter annual weeds in your lawn (henbit, chickweed, and annual bluegrass). Do not apply to your fescue lawn if you plan to overseed.
  • Last nitrogen fertilizer should be applied to your warm-season grasses (Bermuda, zoysia) no later than Sept. 15.
  • Fescue lawns should be fertilized in September and again in November. Fall is the best time to establish or over seed a cool-season lawn. See article below.
  • You have until the end of September to plant cool-season vegetables such as spinach, leaf lettuce and radishes. Click here for fall plant schedule.
  • Spring-flowering bulbs will arrive in garden centers and nurseries during September. Select early for best choices. They can be planted in October and November.
  • Fall is also a good time to plant many ornamentals. Watch for specials at your nurseries.
  • Most trees and shrubs planted in the fall will outperform those planted in the spring. Click here for more details.
  • Before bringing houseplants indoors, reduce the amount of light they receive by placing them under a shade tree. Inspect the plant and soil for pests, hose off with water, and then spray with insecticidal soap or a lightweight horticulture oil before bringing inside.

Overseeding Fescue Lawns

Fescue lawns in the Tulsa County area have been hit hard in the last month with the lack of rain and high temperatures. Even well-irrigated yards have suffered. Remember that fescue is a cool-season grass and high temperatures are a menace. The heat also makes fescue lawns more susceptible to the fungus that causes "brown patch." Aside from proper watering, there is not much you can do to solve these problems.

According to the OSU Extension Service, the best time of the year to overseed fescue lawns is when the temperatures cool in the fall, usually between Sept. 15 and Oct. 15. OSU also recommends using a blend of fescues rather than a single variety. Recommended blends can be found in most lawn and garden stores and nurseries. For overseeding, apply at the rate of 3-4 lbs. per 1000 square feet. Read the bag label carefully. Water regularly so that the soil and seeds do not dry out. And remember: do not apply preemergent herbicides if you plan to reseed. Click here for more information.

Need more information?
Click on any of the links below
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.
Trade names and where to find them   
How to Plant a Tree in Oklahoma Soil
Show and tell.
Landscaping and Gardening for Butterflies
How to attract butterflies to your garden 
Fescue Lawn Care
12-month maintenance calendar.
Bermuda Lawn Care
Ditto above.
Trees for Tulsa
A list of 50 recommended trees with descriptions.
Crape Myrtles
A list of over 100, by size and color.
Oklahoma Proven Plants
The new list for 2010.  State horticulturists, nurseries and growers pick their favorite plants, shrubs and trees.
Current and historical source of rainfall, air temperatures, soil temps and much more.  Click on Bixby station.
Fertilizing Vegetables
Handy chart telling you when and how much to fertilize various vegetables.

4 Ways to
Contact Us
Call: 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.

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