Upcoming Classes and Events

Pollinators

Thursday, January 7, 11:00 a.m. – noon. Master Gardener and Cobb Extension staff member Amy Whitney will present the who, what, when, where, and why of supporting local pollinators, at the Senior Wellness Center, 1150 Powder Springs St SW, Marietta, GA 30064.

Thyme to Read Book Club

Friday, January 8, 10:15 – 11:30 a.m. This month’s book is 1491: New Revelations of the Americas before Columbus by Charles C. Mann.  At the Training Room of the Cobb County Water Lab, 662 South Cobb Drive (at the intersection with Atlanta Rd.).

Create a Rain Garden!

Friday, January 8, noon – 1:00 p.m. Mike Kahle, Master Gardener and member of the Cobb Watershed Stewardship Program staff, will present information about how a rain garden helps clean and control run-off, along with how to design and construct a rain garden of your own. Part of the Lunch & Learn series of Cobb Master Gardeners.  At the Training Room of the Cobb County Water Lab, 662 South Cobb Drive (at the intersection with Atlanta Rd.).

Landscape Changes and Homeowner Associations

Tuesday, January 12, 7:00 – 8:00 p.m. Master Gardener Pam Bohlander offers alternatives to standard landscaping plants that will keep homeowners and HOAs happy. Part of the Gardeners Night Out series of Cobb Master Gardeners.  At East Cobb Regional Library, 4880 Lower Roswell Road, Marietta, 30068.

Cobb Community Gardens

Wednesday, January 27, 6:30 – 8:00 p.m. Quarterly meeting of Cobb community garden managers,  members, and supporters, at the Training Room of the Cobb County Water Lab, 662 South Cobb Drive (at the intersection with Atlanta Rd.).

Suburban Home Vegetable Garden

Tuesday, February 9, 7:00 – 8:00 p.m. Master Gardener Vickie Baroni will tell how to grow your own vegetables and herbs. Part of the Gardeners Night Out series of Cobb Master Gardeners.   At West Cobb Regional Library, 1750 Dennis Kemp Lane NW, Kennesaw, 30152.

Thyme to Read Book Club

Friday, February 12, 10:15 – 11:30 a.m. This month’s book is The Scent of Scandal: Greed, Betrayal, and the World’s Most Beautiful Orchid, by Craig Pittman. At the Training Room of the Cobb County Water Lab, 662 South Cobb Drive (at the intersection with Atlanta Rd.).

Compost and Soil Amendments

Friday, February 12, noon – 1:00 p.m. Master Gardener Eddie Rhoades will explain how to turn poor soil into soil that is plant-friendly. Part of the Lunch & Learn series of Cobb Master Gardeners.  At the Training Room of the Cobb County Water Lab, 662 South Cobb Drive (at the intersection with Atlanta Rd.).

Seed Starting Workshop

Tuesday, February 23, 6:30 – 7:30 p.m. Master Gardener and Cobb Extension staff member Amy Whitney will provide the information you need and hands-on practice for starting seeds of some vegetables and annual flowers indoors. In the second floor classroom at UGA Extension/Cobb County, 678 South Cobb Drive, Marietta, GA, 30060.

North Georgia Gardening Symposium

Thursday, February 25, 8:00 a.m. to 3:30 p.m. For homeowners, Master Gardeners, and landscape professionals. Re-certification credits available: 3 hours for category 24, 1 hour for Private pesticide applicators, 5 CEUs for ISA Arborist (A) and Municipal (M). Chattahoochee Technical College, North Metro Campus, Building D, Room 400, 5198 Ross Rd., Acworth, GA, 30102. Program cost of $35 includes lunch and breaks. Register at 770-528-4550, or online through Chatt Tech.

For additional information about any of the above programs, call our office at 770-528-4070.

Rough Year for Boxwoods in Cobb County

Recently, we have seen a lot of troubled Boxwood shrubs, brought in by County residents, here at the Cobb County Cooperative Extension office. Several samples have been sent to UGA's pathology lab, and although a couple of reports have listed disease pathogens such as Volutella as causing some of the trouble, others have cited root problems as the likeliest cause of decline for the sample.

In particular, wet conditions (remember all that rain we had in spring and early summer?) leading to root decay was noted in more than one report.

Virginia Cooperative Extension's publication Selecting Landscape Plants: Boxwoods explains how to select, plant, and care for Boxwood shrubs, and it includes this information about tolerance of Boxwoods to moist soil conditions:

"Boxwoods can grow in a variety of soil textures (relative amounts of sand, silt, and clay), but too much sand (a low water-holding content) or too much clay (too high a water-holding content and too low an air-holding content) should be avoided. A soil that is well-drained is essential; thus, low areas of the landscape that tend to stay moist or wet do not support boxwood growth."

In other words, Boxwoods are not at all tolerant of soil that doesn't drain well and that stays wet for extended time periods. If more Boxwoods out there are struggling, a closer look at the soil conditions might show that poor drainage is part of the problem.

In addition to being a little bit finicky about soil conditions, Boxwood shrubs here in North Georgia have a full measure of pest and disease problems, but Virginia Cooperative Extension's Boxwoods information page notes that deer typically don't eat boxwood, making it an attractive choice for neighborhoods that are troubled by deer.

For those whose Boxwoods are not doing well right now, Clemson University's publication Boxwood Diseases and Insect Pests contains helpful descriptions and photos of commonly seen Boxwood problems.

UGA's Landscape Alert October 18 blog post Boxwood Blight Update by pathologist Jean Williams Woodward tells about a fairly alarming new Boxwood Blight that has not yet made it to Georgia. The update (click on the linked title to see the original blog post) contains photos and a full description, along with tips that can help keep this disease out of our landscapes. This is the "bottom line" in preventing the spread of this fast-moving disease:

"You won’t get this disease if you don’t bring in any boxwoods. The spores are not wind-borne; they are water-splashed and carried on plants, people, tools, and animals. If you do bring in boxwood plants, make sure they come from a nursery certified to be free of Boxwood Blight."

Specifically, to reduce the spread of this disease, Woodward suggests disinfecting tools that are used on or around Boxwoods and considering propagating your own plants from Boxwoods that are known to be free of this new Blight.

For all Boxwood problems, prevention through appropriate variety selection and careful planting-site preparation and maintenance practices are key to our being able to enjoy healthy, beautiful plants in our landscapes for years to come.

A Soil Test Now Can Save Some Pain Later

When a lawn or garden is doing less well than we are hoping for, in spite of a lot of time and  money spent on planting, fertilizing, and watering, an answer to the question of "what's wrong?" can sometimes be found in the results of a soil test.

To encourage healthy plants, getting the soil "right" is incredibly important. A routine soil test can help by identifying the pH and the balance of major nutrients of the soil in question. In general, soils in Cobb County tend to be more acidic than most turfgrass and garden plants will do well in, but it is actually possible to apply so much limestone to the soil that the pH is raised too high.

When the pH is beyond the most optimal range (which varies, depending on the kinds of plants being grown), the plants are less able to use the nutrients that may have been added to the soil, in either fertilizer or composts.

The value of a soil test, such as one done at the soils lab at UGA, is that it will not only identify the soil's pH and nutrient levels, but it also will provide a recommendation for how much limestone (or not) and specific fertilizers should be applied to benefit the desired plants.

Adjusting a soil's pH is a long-term project. Applications of limestone for raising the pH, or sulfur for lowering the pH, won't make a big difference right away; it takes months to work. If a soil test done now finds that the pH is too low for the desired plants (Bermudagrass, for example), then applying limestone now, or very soon, will give it more time to work ahead of the growing season.

The UGA publication Soil Testing for Home Lawns, Gardens, and Wildlife Food Plots provides instructions for taking soil samples, including that about 2 cups of soil should be brought to the local Cooperative Extension office for sending to UGA. Currently in Cobb County, the routine soil test costs $8, as of Jan. 2016, and it can take seven-to-ten days to get the results, which can be returned via either email or U.S. Postal Service.