The squash and the bees

I planted squash plants among my flowers. They look great and are blooming, but they’re not setting any squash. The blossom falls off before the squash begins to grow. Any help?

Squash grows after it has been pollinated by insects or by hand.

When squash plants bloom without producing squash, it probably means they need help with pollination. Squash plants produce male flowers at first, followed by female flowers a few days later. (You can tell the difference this way: male flowers have a single stamen in the center; female flowers have a four-part pistil, and appear swollen just beneath the blossom.)

According to information at GardenGuides.com, if the female flowers drop off without growing a squash, it means that it didn’t get pollinated by the bees or other pollinators that visit the garden.

Squash flowers are big, so if the bees aren’t doing an adequate job, you can do it yourself.  Use a cotton swab or a small, soft brush to gather the pollen from inside the male flower, and transfer it to the female flower. Or pick a male flower, remove the petals and swirl it around inside the female flower. (Look here for pictures of how this is done). With luck, a squash is born!

Hot news! The August Garden Calendar in Saturday’s Tennessean and at Tennessean.com.

Events

Aug. 4 (and every Saturday this month): Guided garden tours at Cheekwood, 11 a.m. – noon.Tours are free with Cheekwood admission, and no reservation is required. Garden Tours meet at Botanic Hall.

Aug. 5: The Nashville African Violet Club will meet at 1:45 at the Green Hill Women’s Center, 10905 Lebanon Road in Mt. Juliet. To learn more, contact Julie at Julie.mavity@gmail.com

Aug. 11: Celebrate the tomato at the annual Tomato Art Fest in East Nashville’s Five Points area, hosted by Art and Invention Gallery. Events include a Tomato 5K, a Fun Run, costumes, parades, games, art, entertainment, contests, competitions and more family fun. Look here to learn more.

Aug. 12: The Tennessee Gesneriad Society will meet at Cheekwood at the Frist Learning Center at 2 p.m. The program will be a pollinaton/hybridization workshop. For more info contact Julie at Julie.mavity@gmail.com (or 615-364-8459).

Aug. 16: Lunch and Lecture: New & Unique Plants for your Garden, noon – 1 p.m. at Cheekwood. Learn how to add color throughout the season and other helpful tips from Cheekwood’s garden staff. $15 for members, $25 for non-members (includes lunch). Call 615-353-9827 to register.

Aug. 21: Two meetings at Cheekwood’s Botanic Hall:

- The Perennial Plant Society meets at 6:30, beginning with refreshments and plant swap. Program begins at 7 p.m., and the speaker is Audubon naturalist Sherra Owens, presenting “Gardenening On The Wild Side With Nature’s Most Important Plant.”

- The Orchid Society of Middle Tennessee meets at 7 p.m. Michael Wenzel of the AtlanticBotanical Garden will speak on Phalaenopsis species.

Both meetings are open to the public.

Aug. 23: The Middle Tennessee Hosta Society meets at Cheekwood, 6:30 p.m., in the Potter Room. Guest speaker is landscape designer, photographer and writer Troy Marden; his topic: In a Southern Garden: Lessons from 20 Years of Gardening in the South.” To learn more about MTHS, visit
http://www.mths-hosta.com
.

Too hot to bloom!

QUESTION: I have a pot of impatiens that was doing well, but now the flower buds have been dropping off or turning brown before opening. The pot is always in the shade and I keep it well watered and fed. It has nice green leaves, just no flowers. Any idea what could cause this?

If there are no other symptoms – no spotting of the leaves, no rotting of the stems, no powdery coating or other unusual growth – a good guess at the source of the problem would be the long period of extreme heat. Even in the shade it has been extremely hot (remember that day it hit 109 degrees?) and plants in containers may suffer more because the pot can dry out quickly. A plant under stress will shed its flowers first.

By now, with several days of rain and more reasonable temperatures, the impatiens (and many other things) should begin to recover.

This is a good time to mention again, though, an email I received from UT Extension plant disease expert Alan Windham, in which he warned about the development of downy mildew in beds of impatiens. Watch for plants that are losing leaves, that don’t flower, and that have white growth on the undersides of the leaves, he advises. This disease can be extremely damaging, so pull up, bag and dispose of infected plants to keep it from spreading. There’s more about it at UT Extension’s Soil, Pest and Plant Center Facebook page.

…And too hot to plant, too

QUESTION: My daughter has thinned out her iris bed and given some to me.  She has given me the whole plant (bulbs and stems). I know I can not plant them at this time but how do I store them until they can be planted in November or December?  Do I need to cut the stems off now or leave them as is?  Thanks for any information you can provide. 

You’re right, with too much heat and still too little rain, it’s a bad time to plant anything. Irises are pretty hardy so you can wait to plant the rhizomes.

For now, cut the leaves off to about 3 to 6 inches, and remove as much of the soil from the rhizome as you can. Don’t wash them, just brush off the dried soil. Check to make sure there are no rotting places, insects or diseased-looking spots (discard those if there are) and store them in a cool, dry place.

You don’t need to wait until November to plant them. While they’re pretty hardy, they’d still rather be in the ground, so consider planting in September, or after the worst of the summer heat passes.

When you do get ready to plant, here’s a helpful link from the American Iris Society that provides information.

Another reminder about watering: In spite of all the rain lately, we’re still experiencing severe drought conditions in Middle Tennessee. Young trees suffer most. If you planted trees this spring, give them a little extra attention to help them make it through this hot, dry summer. Click here to see the Nashville Tree Foundation’s guidelines and tips to help keep your trees healthy.

Events coming up

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.

Aug. 5: The Nashville African Violet Club will meet at 1:45 at the Green Hill Women’s Center, 10905 Lebanon Road in Mt. Juliet. To learn more, contact Julie at Julie.mavity@gmail.com

Aug. 12: The Tennessee Gesneriad Society will meet at Cheekwood at the Frist Learning Center at 2 p.m. The program will be a polinaton/hybridization workshop. For more info contact Julie at Julie.mavity@gmail.com (or 615-364-8459).

Prevent powdery mildew

QUESTION: How do I keep my beautiful zinnias from getting powdery mildew? It may be too late for this year, but what should I do different next year?

Powdery mildew is a fungus that thrives when nights are moderately cool and foliage stays damp. It travels by airborne spores, and appears as gray or white splotches on leaves, stems and flowers of susceptible plants, such as zinnias. A mild case is merely unattractive; a severe case of powdery mildew can cause distorted shoots and leaves, misshapen flowers or can prevent flowering altogether.

The best defense is to give zinnias room to grow without crowding, which allows air to circulate better around the plants, and water only in the morning, so the foliage has time to dry before nightfall. Cut back on the use of high-nitrogen fertilizer, which produces succulent new growth that is a major powdery mildew magnet. Grow them in full sun; hot temperatures (above 90 degrees) inhibit the growth of mildew.

There are fungicides available that should be applied as soon as you begin to spot the mildew (so yes, probably too late for this year), but I always suggest trying the good-cultural-practices method first. The University of Tennessee Extension has a short list in a publication about powdery mildew here. If you decide to go that route, be sure to read and follow directions on the product label.

Zinnias are not the only things plagued by powdery mildew. Lilacs, roses, crepe myrtles and other woody ornamentals, and many herbaceous ornamentals and bedding plants are also targets when weather conditions favor the fungus.

Coming up

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 at 6:30; meeting and program at 7. Guest is Kelly Norris, horticulturist, plant breeder and manager of Rainbow Iris Farm in Bedford, 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.

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.