Powdery problems

I have three peonies. Two are fine, but the third, in a different location, is completely covered with powdery mildew. How does that happen? Should I do something about the one that’s covered? Or just leave it and hope for the best?

Powdery mildew (which affects all kinds of plants in the landscape) can be a problem when weather conditions are right and cultural conditions are less than perfect. It’s a fungus that thrives in warm weather when the humidity is high. It becomes more of a problem for plants that are growing in damp, shady places and overcrowded conditions.

It’s a common disease and you’ll know when it hits: look for patches of gray-white, powder-like growth. It usually appears on the tops of leaves but can also be seen on the bottoms of leaves, and on young stems, buds and flowers. It likes the young, succulent parts of plants.

At the UT Extension Soil, Plant and Pest Center, expert Alan Windham (who frequently provides answers to questions here) says the peony should survive with no problem. It’s a good idea to remove any dead or dying foliage and destroy it (don’t put it in the compost; that probably won’t kill the fungus spores), and clean up around the area.

Windham is more worried about downy mildew in beds of impatiens, which we mentioned in this column several weeks ago. “There are lots of cases coming in from all over the state; it’s been found in nearly every state east of the Mississippi,” he says.

Watch for plants that are losing leaves, that don’t flower, and that have white growth on the undersides of the leaves, he advises. The disease can be extremely damaging, so pull up, bag and dispose of infected plants to keep it from spreading.

Bad news this year, but even bigger implications for next year regarding availability, use by commercial landscapers and their general viability as a bedding plant, he said. Does that mean the ubiquitous impatiens won’t be among the gardener’s favorite go-to shade annual next year?

“Begonias, SunPatiens and New Guinea impatiens are going to be in high demand,” he says.

If you haven’t seen the Soil, Pest and Plant Center’s Facebook page, check it out here. “We’re putting lots of good stuff up,” Windham says.

Garden events in MiddleTennessee

Sept. 5:WarnerParkNatureCenter hosts Hummingbird Happy Hour, 4 – 6 p.m. at the WarnerParkNatureCenter. Bird banding demonstrations and other kid-friendly activities are on the agenda. Free admission, but registration is required; call 352-6299. While you’re there, visit the NatureCenter’s vegetable, herb and flower garden. Info: http://www.nashville.gov/parks/nature/wpnc.

Sept. 15: Urban Chicken Appreciation Day at Shelby Bottoms Nature Center, 10 – 11 a.m., celebrates feathered backyard friends. Learn how to get started in backyard chicken keeping in a session led by Bonnie Bowles. Call (862-8539) or email (shelbybottomsnature@nashville.gov) to register.

Sept. 22 & 23: Many rare and unusual houseplants will be available at the Tennessee Gesneriad Society’s annual Flower Show and plant sale, which will be held at Cheekwood’s Botanic Hall. The event is open to the public 9:30 a.m. – 4:30 p.m. Saturday, and 11 a.m. – 4:30 p.m. Sunday. To learn more contact Julie Mavity-Hudson at Julie.mavity@gmail.com.

Sept. 29: Herb Society of Nashville’s Herb Day at Cheekwood’s Botanic Hall: “Cooking & Gardening with Native Plants.” 9 a.m. – 4 p.m.; admission is $40 plus Cheekwood gate fee. To register: www.herbsocietynashville.org.

Evergreens turning ever-brown

QUESTION: We are seeing many evergreen trees — Leyland cypress and others — with big sections of brown limbs. Is that due to the drought? Or is there some other problem affecting the trees?

The drought this summer plays a big part in the browning of Leyland cypress, but it’s not the whole story. Alan Windham, at UT Extension’s Soil, Pest and Plant Center says the branch dieback is the result of a one-two punch: drought and seirdium canker, a fungus that appears on branches or stems and in branch axils and causes the branch to die. “I’ve seen more damage this month than I can remember in several years,” Windham says.

I found a good description of seirdium canker at the Web site of North Carolina State University’s Plant Pathology Extension: The cankers are brown or purple sunken patches on the bark, and may be accompanied by a flow of resin. Affected branches may be scattered randomly throughout the tree; they turn a reddish-brown color, in striking contrast to the green, healthy foliage. The fungus can be spread by splashes of rainwater or water from sprinklers, or it can travel from branch to branch on unclean pruning tools.

There are no chemicals recommended to control the canker. Brown branches should be pruned and destroyed as soon as possible. Prune at least an inch below the canker, and sterilize the pruning tools between cuts by dipping them in rubbing alcohol or a solution of 1 part chlorine bleach to 9 parts water. Plants that are severely affected should be removed and destroyed. Watering by drip irrigation during drought can help prevent problems, Windham says.

Upright arborvitae are also having trouble due to the drought. Windham explains: Plants have different strategies to survive: some plants sacrifice older leaves to protect new shoots; some have waxy leaves, some plants roll their leaves or close up to prevent water vapor from escaping.

“Then you have plants like arborvitae, where it’s all or nothing. It’s as if the plant is saying, ‘We’re going for broke. Everything survives or nothing survives.’ Well, this strategy didn’t work out too well for many arborvitae I have seen.”

In this case, the only solution is to remove the dead trees and start again.

Garden events in Middle Tennessee

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 www.mths-hosta.com.

Next month in Middle Tennessee

Sept. 5:WarnerParkNatureCenter hosts Hummingbird Happy Hour, 4 – 6 p.m. at the WarnerParkNatureCenter. Bird banding demonstrations and other kid-friendly activities are on the agenda. Free admission, but registration is required; call 352-6299. While you’re there, visit the NatureCenter’s vegetable, herb and flower garden. Info: http://www.nashville.gov/parks/nature/wpnc.

Sept. 15: Urban Chicken Appreciation Day at Shelby Bottoms Nature Center, 10 – 11 a.m., celebrates feathered backyard friends. Learn how to get started in backyard chicken keeping in a session led by Bonnie Bowles. Call (862-8539) or email (shelbybottomsnature@nashville.gov) to register.

Sept. 22 & 23: Many rare and unusual houseplants will be available at the Tennessee Gesneriad Society’s annual Flower Show and plant sale, which will be held at Cheekwood’s Botanic Hall. The event is open to the public 9:30 a.m. – 4:30 p.m. Saturday, and 11 a.m. – 4:30 p.m. Sunday. To learn more contact Julie Mavity-Hudson at Julie.mavity@gmail.com.

Sept. 29: Herb Society of Nashville’s Herb Day at Cheekwood’s Botanic Hall: “Cooking & Gardening with Native Plants.” 9 a.m. – 4 p.m.; admission is $40 plus Cheekwood gate fee. To register: www.herbsocietynashville.org.

Melons: Ripe and ready

QUESTION: I am growing melons — watermelon and cantaloupe – for the first time. How can you tell when the fruit is ready to pick?

Nothing could be more frustrating than cutting into a freshly picked watermelon and finding that it is not completely ripe. Before you cut the melon from the vine, look for these clues:

Turn the watermelon over. The ground spot (where the watermelon rests on the ground) should be creamy yellow. If the spot is white, the melon is not ready.

On a watermelon, there is a tendril growing at the end of the fruit. If it is still green, give the melon a few more days to ripen. If it is half-dead, it’s likely the melon is ripe or nearly so.

Give it a thump. A ripe watermelon sounds hollow (though some say it’s difficult to really hear this).

Cantaloupes and other small melons don’t have the tendril or a significant soil spot, like watermelons, but there are other clues. Cantaloupes, which have netted rinds, develop a golden color under the netting when the melon is ripe. They also soften at the end opposite the stem when they ripen, which you can feel if you press gently. Ripe cantaloupes also have a sweet fragrance. It will also separate easily from the vine

Events in Middle Tennessee

Aug. 11 (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. 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.

Grow the best blueberry bushes

QUESTION: I have had blueberry bushes for 2 years and they still look awful. I’ve been told to put coffee grounds around them but they don’t grow or produce fruit.  We have them in a bed with some calla lilies which are doing very well. The plants were healthy plants from the co-op.  I have a friend in Clarksville that has lush bushes with lots of fruit.  I asked if they did anything special and she said “no”.  Any tips to help us would be appreciated. — Karen in Donelson

Blueberries need sun, water and the proper soil pH to produce a good crop.

Blueberries are pretty finicky about what they need to grow well and produce, so I’ll let you know what those needs are, and you can decide if they’re getting what they require.

Do you know what the variety of your plants? Different types are adapted for different regions, and in Middle Tennessee, the varieties called rabbiteye and southern highbush blueberries are the most reliable choices.

Furthermore, they are not always self-fertile, which means you need more than one variety for cross-pollination to take place (and the insects buzzing around to pollinate them at the right time).

Now, the soil. Blueberries require acid soil, with a pH level of 4.5 to 5.6, so if you don’t have that information, have the soil tested. Coffee grounds are acidic, and that’s why the addition of coffee grounds may have been suggested. The fact that the calla lilies are doing well suggests that the pH might be part of the problem; they grow better in soil that is more alkaline. Blueberries also require soil that is well-drained, so make sure they’re planted in a place that doesn’t stay wet.

They need full sun, and they don’t like to compete with grass and weeds, so mulch around them with shredded bark or compost to keep weeds under control. They also suffer during times of drought because of their shallow roots, so make sure they get sufficient water (about once a week in dry weather, suggests garden expert Felder Rushing in his book, Guide to Tennessee Vegetable Gardening).

Blueberry bushes benefit from the same type of fertilizer as azaleas (which also need acid soil to grow well). Apply fertilizer, following label directions, in the spring.

Your friend who has lush bushes and lots of fruit may not be doing anything special, but it sounds like her plants are the right type for the area, in soil they like, and are getting plenty of sun and enough water. With a little more care and attention, yours may also re-gain their health.

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.