The drought takes a toll on trees

QUESTION:  I have a concern about two hackberry trees in my yard. They are quite old and beautiful, but the leaves are turning yellow and are falling off rapidly.  Is this due to the high heat or another problem? I would sincerely hate to see these lovely trees die.  

During drought, a hackberry’s leaves may turn yellow and fall. Mature, healthy trees should recover.

Let’s just say that while the high heat is a major culprit in the early-summer yellowing of a lot of things, it’s not acting alone. “It’s drought primarily,” says Alan Windham, the ornamental and turfgrass pathology expert at U.T. Extension.

“I actually witnessed this, this morning on hackberry behind my home while walking my dogs,” he said when I sent him this question earlier this week. “It was breezy, and yellow leaves were falling from the hackberry like a fall day.”

Most likely, this leaf-fall is not a fatal condition. “Most mature trees have survived many droughts, and should be able to survive this one,”Windhamsaid. “Regardless, I’m hoping for rain this week.”

Young trees that haven’t had a chance to develop an extensive root system are more vulnerable. An email alert from the Nashville Tree Foundation, which plants trees in public places and private yards on its ReLeafing day each November, has sent an alert with watering guidelines and new tips that you can read here to help young trees survive. Most important: water thoroughly, and water slowly to prevent run-off.

The long-range weather forecast may show some relief. Next week, it looks like temperatures will be in the more reasonable mid-to-upper 80s, with a chance of rain.

Coming up

July 14:  Middle Tennessee Iris Society rhizome sale, 8 a.m. – 3 p.m. at Ellington Agricultural Center. All types of irises available in a variety of colors, priced from $1 – $6. A great chance to add to your collection! To learn more: For additional information see our web site www.middletnirisociety.org.

July 17: Middle Tennessee Orchid Society meets at 7 p.m at Cheekwood. On the agenda: an orchid auction and discussion on Cattleya Orchids. To learn more, visit www.tnorchid.com.

July 17: Perennial Plant Society meets at Cheekwood in Botanic Hall. Refreshments and plant swap at6:30; meeting and program at 7. Guest is Kelly Norris, horticulturist, plant breeder and manager of Rainbow Iris Farm inBedford,Iowa will present “The Modern Plant Explorer.” The meeting is open to the public.

July 26: Farmer Jason performs at Family Night Out at Cheekwood, 6:30 p.m. The event is free with regular Cheekwood admission. www.cheekwood.org.

Keep African violets blooming

QUESTION: My African violets were blooming beautifully when I got them a few months ago, but no longer. How can I get them to bloom again?

It’s easy to love those dainty clusters of blossoms rising from rosettes of downy leaves. African violets look like they’d be fussy plants, but quite the opposite: “They’re easy to grow if you know a few secrets,” says Julie Mavity-Hudson of the Nashville African Violet Club.

One of those secrets may surprise you: African violets tend to bloom better when they’re slightly root-bound, so don’t rush to move them to larger pots. They thrive in bright, indirect light and average room temperatures, in soil that is kept slightly moist. “The thing that kills more African violets than anything is overwatering,” Mavity-Hudson says.

Failure to bloom might be because the plant is not getting enough light. In winter, when the light is low, try moving it to a south or west window where the light is brighter, but move it away from the window when the light is more intense. Direct sun will burn the leaves of African violets.

A light feeding of high-phosphorous plant food every few weeks may also help. Houseplant expert Barbara Pleasant (The Complete Houseplant Survival Manual) suggests adding a light pinch of Epsom salts to water to push balky plants into bloom.

To get together with other African violet aficionados, check out the Nashville African Violet Club, which meets the first Sunday of most months,1:45, at the Green Hill Women’s Center,10905 Lebanon RoadinMt.Juliet. The meetings are open to the public.

Events coming up

– Professional Landscape Association of Nashville, Tennessee – P.L.A.N.T. – will hold its winter seminar Thursday (Jan. 12),8 a.m. – 4 p.m., in Massey Hall atCheekwoodBotanical   Garden. The day’s topics include “Right Plant Right Spot,” by Kerry Mendez; “Pruning Techniques & Best Management Practices” by Karla Kean; Perennial Plant Collector’s Corner by Kerry Mendez; and “Longwood Gardens’ Vision for Horticultural Excellence and Beauty,” by Rodney Eason. Registration at the door is $100 for P.L.A.N.T. members, $125 for non-members (includes lunch). To learn more, visit P.L.A.N.T.’s Web site here.

–Another reminder that the Nashville Lawn & Garden Show is March 1 – 4 at the Tennessee State Fairgrounds. This year’s theme is Gardens Past, Present & Future, and as always the show features beautiful live gardens, 250 exhibit booths, a floral design gallery and a roster of free lectures.

Peter J. Hatch. The Thomas Jefferson Foundation Inc. at Monticello, photo by Robert Llewellyn.

Peter J. Hatch, Director of Gardens and Grounds at Monticello, the home of Thomas Jefferson, is one of this year’s speakers. Hatch is scheduled to speak on Friday, March 2 about “Thomas Jefferson’s Revolutionary Garden,” which featured more than 330 varieties of vegetables. On Saturday, March 3, Hatch will discuss Jefferson’s use of native plants, the union of gardening and sociability, and his experimentation with useful plants as a means of social change in his talk, “Thomas Jefferson, Gardener.” Other popular speakers are returning: Jeff Poppen, The Barefoot Farmer from Long Hungry Creek Farm in Red   Boiling Springs,Tenn.; Rita Randolph of Randolph’s Greenhouses from Jackson, Tenn.; and Justin Stelter, historic gardener for Carnton Plantation in Franklin and The Hermitage, Home of Andrew Jackson. Information about these free lectures is at the Nashville Lawn & Garden Show Web site.

Admission will be $10 for adults ($9 if you’re 65 or older), and this year the Tennessee State Fairgrounds will charge $5 per vehicle to park during the show. The Web site promises group discount and coupon offers coming soon.

Just water, please

Last summer, when it was very hot, I ran my dehumidifer upstairs when it was impossible to cool and used the water to water my indoor plants. Within a week or so they perked up like they were new plants, so I’m wondering how to duplicate that water, or what do you suggest? I have tried plant food, tea water, etc. and nothing works like the water from my dehumidfier. -S.W.

Houseplants may benefit from water that is free of added chemicals.

A likely explanation might be that since the water in a dehumidifier is “collected” from the air, nothing has been added — no chlorine or fluoride, such as we have in tap water. A lot of houseplants are sensitive to the additives in tap water, especially fluoride, according to my favorite source on caring for houseplants, author Barbara Pleasant’s Compete Houseplant Survival Manual.

You may be able to duplicate that unadulterated water by letting tap water sit out overnight before watering plants with it; supposedly that allows the chlorine and other chemicals in the water to escape. Or you could try using distilled water, or collect rainwater to use on your plants.

The author goes on to suggest using water that is at room temperature when you give it to the plants. “Giving cold water to tropical plants chills their roots, which can cause them to rot,” she writes.”

Spring is coming!

Dates for the 2012 Nashville Lawn & Garden Show have been set. Plan to head to the Tennessee State Fairgrounds March 1 – 4 to enjoy Tennessee’s largest and most popular annual gardening event. This marks the show’s 23^rd year, and the theme this time is Gardens Past, Present & Future. Details should be coming soon to the show’s Web site.

Waterfalls were featured in many of the 20 live gardens at last year’s Nashville Lawn & Garden Show.