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July 2017
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Pick your poison, carefully

Green stink bug on poison ivy. (C) Jo Ellen Meyers Sharp

In the NCIS episode “Viral,” McGee tells Bishop to be careful because the area they are investigating (outside Washington, D.C.) is covered with poison oak. In fact, there have been warnings about poison oak in several “NCIS” episodes.

Those California-based writers probably don’t realize that poison oak (Toxicodendron diversilobum) is rarely found outside the western United States. The leaves of this native plant resemble oak leaves, which accounts for its common name. It can be a vine or a shrub.

Poison oak. Photo courtesy US Forestry Service

There is Atlantic poison oak (T. pubescens), a native vine or shrub-like plant. Although uncommon, it is found in Illinois and states south and east, but not in Indiana.

Much more common in the eastern half of the U.S. is poison ivy (T. radicans). It’s so common that we frequently find this native plant in our yards, whether we live in urban, suburban or rural areas. Poison ivy can take the form of a climbing vine or as a shrub. The most identifying characteristic is “leaves of three, let it be.” It has beautiful fall color and showy berries.

Poison sumac. © Troy Evans /Bugwood.org

Poison sumac (T. vernix) also can be found in Indiana, especially along riverbanks or swampy areas, where it grows as a shrub or small tree. Its leaves are opposite each other on slightly arching branches.

Poison ivy, poison sumac and poison oak all contain urushiol, an oil that causes the rash or welts associated with exposure to these plants.

Another native plant, Virginia creeper (Parthenocissus quinquefolia) is sometimes mistaken for poison ivy, primarily because the leaves look similar. But Virginia creeper has five leaflets to a leaf and it climbs by tendrils and suction cup-like appendages. It has purple fruit and beautiful fall color. The leaves and stems of this plant contain crystals of calcium oxalate, called raphides, which can cause dermatitis on some people.

Virginia creeper scampers over cheddar pinks. (C) Jo Ellen Meyers Sharp

What’s a gardener to do? I always wear long sleeves, jeans and gloves when pulling Virginia creeper from my neighbor’s fence or other places in my yard. If I find poison ivy, I cover my arm with several plastic sleeves that newspapers come in. I pull the poison ivy, then pull the plastic sleeve over my hand and toss bag in the trash.

There are products you can apply that provide a barrier to these plants’ irritants. And if skin is exposed, there are specialized products to clean the area. Your pharmacist can make recommendations. Always read and follow the label directions.

Remember to use care when taking off clothes worn when working with these plants. The oil can remain on the material and be transferred to your skin. Consider washing garments that were exposed to the oils twice.

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Rain and more rain, and a garden, too

Carolina Moonlight baptisia stands tall in the rain garden at the Indianapolis Museum of Art. Photo courtesy Irvin Etienne

A Facebook friend reported that his Muncie, Indiana, garden received 30.1 inches of rain between April 28 and July 6, which he said was 75 percent of his annual rainfall. Indianapolis’ average annual precipitation is about 42 inches.

It’s hard to know if we should be grateful for the rain or curse it. I know we’d be cursing if we didn’t have rain.

Make sure containers of flowers, tomatoes, herbs and other plants are draining well. I had a very large pot that had drainage holes plugged with soil. I poked a sturdy stick in the holes and water gushed out.

We should also keep up with fertilizing plants in the ground, but especially in our pots. All of the rain is washing nutrients away, especially nitrogen. It’s not good to over fertilizer because the rain is already pushing plant growth. All the rain could also be turning plants’ leaves yellow. Consider an extra half dose of fertilizer instead of a full one.

Rain-enhanced Plant Growth Invites Insects, Disease

With All This Rain, Plants Can Drown

Rain gardens or swales

Several people have written asking about areas of their landscape that periodically retain water for several days or stay fairly wet most of the time. For some, it’s a drainage ditch. For others, it’s a low place in their yard or an area where there’s a lot of runoff, such as the bottom of a slope.

First, consider consulting with a landscape architect, contractor or designer to give a professional opinion. There also may be some guidance available from the Marion County Soil and Water Conservation District (http://marionswcd.org). Sometimes, excavation may be necessary along with the installation of layers of different materials, such as stone, gravel, sand or special kind of soil mix, to achieve a successful rain garden or bioswale.

Rain gardens are effective ways to handle run off from hard surfaces, such as parking lots, sidewalks and streets. The goal of some rain garden is to reduce pollutants that might come in that runoff before it hits the water table. Some examples can be found along Alabama Street downtown. A bioswale transforms a drainage ditch into something beautiful and environmentally friendly.

What to plant, they ask. There are a lot of perennials and shrubs that do well in this type of growing conditions, whether is shady or sunny. Some resources:

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Bee balms evaluated for mildew resistance and flower power

Powdery mildew is a common problem on many bee balms. (C) Jo Ellen Meyers Sharp

One of the perennials known to attract pollinators is bee balm (Monarda spp.). A member of the mint family, this aromatic plant attracts and supports at least 14 butterflies and moths, 13 bees and wasps and hummingbirds, finches, sparrows, catbirds.

“Today, people are increasingly aware that their landscapes provide not just beauty, but also play a role in improving the environment,” wrote George Coombs, research horticulturist at Mt. Cuba Center in Hockessin, Delaware, not far from Wilmington. “With the ability to support a multitude of different pollinators, Monarda is well positioned to capitalize on this growing trend and will continue to be a popular garden plant for years to come.”

Coombs’ group recently evaluated bee balms, and although the Delaware Piedmont is a different environment than our Midwest, the results can be a guide for our plant selections. At Mt. Cuba, 40 varieties of bee balms were trialed for three years. They were evaluated for their growth habit, leaf retention, flower coverage, and perhaps most importantly, resistance to powdery mildew. Powdery mildew is a common problem on bee balms, including several native varieties. Powdery mildew is a fungus that appears on monarda about the time it starts blooming. It is not usually deadly, but can cause leaves to dry, curl and fall off.

‘Purple Rooster’ was among the bee balms that showed resistance to powery mildew and good flower power. Photo courtesy PerennialResource.com

None rated excellent, or five stars, but there are several that received four and one-half stars: ‘Claire Grace’ (M. fistulosa), ‘Dark Ponticum’ and ‘Violet Queen’. Those that earned four stars: Grand Marshall, ‘Judith’s Fancy Fuchsia’, ‘Colrain Red’, ‘Raspberry Wine’, ‘Purple Rooster’, ‘On Parade’ and ‘Gardenview Scarlet’. My favorite, ‘Jacob Cline’ (M. didyma) scored slightly lower than the top performers, and could still be recommended, the Mt. Cuba Center report said. Many of the species also showed resistance to powdery mildew.

“The first signs of infection typically appeared in July as the plants started to flower. Flowering requires a significant amount of energy and resources, and this stress can make plants vulnerable to infection. It is therefore important to prevent/reduce infections by limiting the amount of stress a plant experiences. For Monarda, this might be accomplished by providing adequate water during its flowering period. Dividing older clumps every few years may also help to reinvigorate tired and stress-prone plants,” the report said.

During the evaluations, the researchers tried several methods to control the fungus disease. Plants were cut back to the ground when the disease showed up, cut back by half, and some were deadheaded, but none was successful in getting plants to flush out new growth.

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Gift of hydrangeas to adorn museum grounds

Bloomstruck hydrangeas were among 75 plants Bailey Nurseries donated recently to the Indianapolis Museum of Art.
Photo courtesy Irvin Etienne

Endless Summer may be the best selling series of hydrangeas, but they frequently come with a lot of questions, with the main one being “why won’t my plants bloom?”

For answers, I went to the source.

Ryan McEnaney is a public relations and communications specialist at Bailey Nurseries in St. Paul, Minnesota. He’s a third generation member of the Bailey family, which has been breeding and selling plants for nearly 120 years. Bailey introduced Endless Summer hydrangeas in 2004, marketing them as rebloomers. For gardeners, that translates into flowers all summer long.

With perhaps a slight smile, he suggested mulching Endless Summer hydrangeas 6 to 12 inches of chopped leaves to protect them through winter. The flower buds, which are formed late in summer for the following year’s blooms, frequently get frozen when temperatures take a dip in spring. The mulch protects the plants from that danger. “But who is going to do that,” I asked? We both laughed and agreed not very many of us.

Bloomstruck’s long season of flowers makes it perfect for a summer container on the porch, patio or balcony, or as a focal point in the garden. Photo courtesy Bailey Nurseries

Reblooming hydrangeas bloom in early summer on stems that wintered over and then later on current season growth to provide flowers all summer. Whatever you do, don’t prune them until the plants have leafed out fully in spring. And then remove stems that have not leafed out or cut them back to where there are green leaves, he said.

“Don’t over fertilize them, which just encourages green growth,” he said. “Fertilize once in spring and if you think it’s needed, in summer.”

He said Bailey’s newer introduction of BloomStruck has hardier flower buds, which makes them handle winter better. Other tips: plant them in a partly shady location and water regularly.

McEnaney was in town recently to donate 75 woody plants, including Bailey’s Endless Summer BloomStruck hydrangeas (H. macrophylla), to the Indianapolis Museum of Art. Also in the mix were Bailey’s First Editions’ Jetstream oakleaf hydrangea (H. quercifolia) and Summer Cascade wisteria (W. macrostachya), two new cultivars of native plants.

Irvin Etienne, horticultural display coordinator at the IMA, said Bailey’s donation allows the museum to try new plants in areas that need attention while freeing up the budget for other improvements.

Blue or pink big leaf hydrangeas?

Big-leaf hydrangeas (H. macrophylla), such as BloomStruck, Let’s Dance and many others, will have pink flowers in Indiana and other Midwestern gardens, because our soil tends to be alkaline (high pH). An acidic soil (low pH) is what turns the flower color into the blue range. Here are some more tips.

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With all of this rain, plants can drown

Heavy rains can drown plants. (C) Carol Michel/maydreamsgardens.com

We’ve had a lot of rain. We already know that the rain has promoted fast growth and early blooms on perennials, trees and shrubs. It’s also contributed to disease problems, especially fungi, for many plants.

All the rain can cause the soil to be waterlogged, which means there’s decreased oxygen available for plants. A lack of oxygen can cause plants to drown. As of this writing, we’ve received 26.05 inches of rain. Our average is 19.65 inches.

“It is important to understand what is happening to plants growing in these conditions and what to expect later. I look at this as a wait-and-see situation,” wrote

Rhonda Ferree, a horticulture educator at the University of Illinois Extension, in a recent report.

Visible injury to trees and shrubs may not show up for a year or two. Waterlogged soil deprives roots of oxygen, reducing the ability of trees or shrubs to take up and provide necessary nutrients. That lack of nutrients is what may cause decline or damage. Perennials may already show an overall decline because of waterlogged soil.

Ferree also notes that flooded yards add a lot of weight to the soil, which may cause compaction. That also pushes oxygen from the soil, inhibiting a plant’s ability to take up nutrients.

“Although survival is directly related to a species’ tolerance of waterlogged soils, other factors are important, including the soil type; the time, duration and depth of the water; the state of the floodwater; and the age and size of woody plants,” she said.

“Unfortunately, little can be done to prevent damage to plants growing in waterlogged soils. If a woody plant shows injury symptoms, such as leaf drop, do not immediately replace it. Some plants will show initial injury symptoms and then recover”

Injury symptoms, which vary according to several factors, include slower shoot and root growth, leaf yellowing, leaf twisting, leaf drop, root death, increased susceptibility to attack by insects and disease, absence of fruiting, and death.

Some will recover and some may not, providing yet another example of how gardening teaches us patience.

Indy gardener pots and prunes blog posts into book

Carol Michel. Photo courtesy Jill Thompson

Carol Michel has come a long way since I first interviewed her shortly after she won the 2009 Mouse and Trowel Award for MayDreamsGardens.com, voted the best blog by readers from all over the country.

“I love writing, and blogging gave me a way to write about gardening and share what I wrote almost immediately with others,” she said at the time. Michel, who grew up in Greenwood, Indiana, and has been blogging seriously since 2006.

Since then, Michel, who has a degree in horticulture from Purdue University, wrote a garden column for a south side community paper for a few years, writes regularly for gardening magazines and began accepting speaking gigs. And she’s won other awards for her blog from the National Society of Newspaper Columnists and Garden Writers Association, of which she’s a member.

She retired a year ago after 30-plus years in information technology and almost immediately started on a book. Published earlier this year, Potted and Pruned pulls from Michel’s blog, showcasing her practical advice, heavily seasoned with her unique sense of humor.

“After 10 plus years of blogging, I felt like I had some good essays about gardening that were trapped in the online world. By putting some of the essays in a book, potting them up and pruning them first, I hoped to reach a new audience of gardeners who haven’t discovered garden blogs,” she said in an interview

Michel, who declares herself a Gardenangelist, published the book under Gardenangelist Press. She worked with Deb Wiley, a freelance editor in Iowa, and with a former Indianapolis resident, Katie Elzer-Peters of Wilmington, North Carolina, who served as managing editor. Elzer-Peters fostered the book through the publishing process, and coordinated the design and graphics. The book is available in hard and soft cover and Kindle at Amazon.com, or signed copies are available from her blog.

Michel, who claims to have the world’s largest hoe collection with 56 of the tools, embraces the old-fashion and historic aspects of gardening. She prowls used bookstores and lurks online auction houses, searching for first editions of garden books, such as those by Elizabeth Lawrence (1904-1985) or Cynthia Westcott (1898-1983). Michel has made the pilgrimage to Wing Haven, Lawrence’s home and garden in Charlotte, North Carolina. She was so impressed with Westcott’s ability to write about plant pathology in a way that was easily understandable, Michel helped create an award from Garden Writers Association to honor academics who communicate complex horticulture information in language a gardener can understand.

“I read once that the Smithsonian Museum and other archivists would far rather preserve something on paper than in an electronic format,” she said. “Though I don’t think my book is by any means worthy of a museum, I hope that someday a gardener discovers it in a used bookstore, the way I’ve discovered old gardening books in used bookstores.”

 

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Summertime blues are here early

Larkspur. (C) Jo Ellen Meyers Sharp

Three clematis and larkspur are showing their summer blues.

I don’t know how many years I sowed seed for annual blue larkspur (Consolida ajacis), but I could never get it going. Then, one year, a glorious stand of ferny foliage and blue spikes appeared. Ever since, the larkspur has self-sown its way into a larger patch and in a few other places. At about 3 feet tall, larkspur provides seasonal height in the garden and is perfect for fresh-cut bouquets.

Two new and one standby clematises are blooming, all a bit early. ‘Jackmanii’ has been climbing a wrought iron structure on my porch in morning sun since the early 1990s. It has large, star-like purple flowers all along its 6-foot length. If this beauty has a drawback, it’s that it gets clematis wilt, a fungus disease that shows up just as the plant is in its full glory.

Sapphire Indigo clematis. (C) Jo Ellen Meyers Sharp

The large-flowering clematis varieties are the most susceptible to this problem. The fungus resides in the soil and when summer temperatures heat up and the humidity rises, the disease shows up.

First, the vine looks wilted, then the leaves and stem turn brown. Cut out any diseased stems below the soil line. The Missouri Botanical Garden recommends spraying remaining stems and the surrounding soil with a protective fungicide, such as myclobutanil. The ingredient is used in organic farming, but remember that fungicides are deadly to bees, so always read and follow the label directions.

Rooguchi clematis. (C) Jo Ellen Meyers Sharp

‘Rooguchi’ clematis has been around for a while, but it’s new for me. I planted it last year and this year, it is beautiful. This one has large, blue, bell-shaped flowers on vines about 6 feet tall. I have it growing up an obelisk in full sun. It blooms all summer and does not get clematis wilt.

Sapphire Indigo clematis only gets about 3 feet tall is loaded with flowers the color of the plant’s name. This summer-long bloomer has flowers are about 3 inches wide with curved petals. This is not really a climbing clematis, but more of a trailing type. However, mine trained nicely on a 3-foot tall obelisk in a perennial bed that gets morning sun. Sapphire Indigo was planted last summer and it is in full bloom. This clematis is said to have good disease resistance.

 

Rain-enhanced plant growth invites insects

Rose slug and damage. Photo courtesy Missouri Botanical Garden.

There seems to be a lot to be on the lookout for this spring.

For instance, I noticed finches sitting on the branches of the ‘Goldflame’ honeysuckle vine, pecking at the flower buds. A closer inspection revealed aphids on the buds, so I’m assuming (hoping?) the birds were eating the bugs. Aphids frequently are drawn to tender new growth and the recent rains have promoted that.

My native columbines (Aquilegia canadensis) have lost all of their leaves. More accurately, the caterpillar stage of the wasp-like columbine sawfly has been devouring them. Fortunately this is an aesthetic problem and not likely to kill the plant, unless an infestation occurs several years in a row. The native columbine is supposed to be more resistant to the sawfly’s green caterpillar, so I’m hoping this is just a fluky occurrence.

 

Tiny bugs called leaf miners make track in the leaves of columbine.

Columbines are susceptible to leaf miner damage, too. The culprit is the larval stage of a native fly. Tiny caterpillars leave telltale tracks in the leaves as they eat their way through the layers of green tissue.

Another kind of sawfly caterpillar, commonly referred to as the rose slug, makes holes in the plant’s leaves. The green caterpillars chew holes on the undersides of rose (Rosa) leaves, usually only in the morning.

My phlox, salvia and a few other perennials show damage from what’s commonly called a plant bug. As generic as that sounds, there are a few insects that do this type of damage, but it likely is the one-fourth inch long tarnished plant bug. It makes tiny brownish or brown-black holes in the leaves or flower buds.

A plant bug has been taking bites out of the leaves of phlox (pictured), salvia and a few other perennials. (C) Jo Ellen Meyers Sharp

Again, the damage from leaf miners, rose slug and plant bug is more aesthetic than deadly. The first line of defense is a strong spray of water from the end of the garden hose to knock the unwanted critters from the plants. Be sure to spray water on the undersides of the leaves, too. Do it every few weeks until you have the problem under control.

 

Dogwood anthracnose can be a killer

 

Leaves from this native dogwood (Cornus florida) were sent to Purdue University’s Plant Pest Diagnostic Laboratory. The diagnosis: dogwood anthracnose had infested the tree (Cornus florida). (C) Jo Ellen Meyers Sharp

The other day while gazing out my front window, I noticed the leaves on one of the two flowering dogwood trees looked very small. I darted out of the house to get a close look and was shocked to see most of the leaves were brown and curling. The flower petals, called bracts on dogwoods, were shriveled and the ground was covered with their bits and pieces.

Oh, dear, I thought. I wonder if this could be dogwood anthracnose, a fungus disease that I have only read about.

I snipped off some leaves, put them in a disposable plastic container, boxed it up and mailed it off to Purdue University’s Plant Pest Diagnostic Lab (http://bit.ly/2qEo6p2) along with an $11 check and a form that described symptoms, size of tree and other details.

Two days later, I got the results: two types of fungus, dogwood anthracnose and spot anthracnose, with the first one causing the most damage.

Dogwood anthracnose can be a deadly disease on this much-loved native tree (Cornus florida). Not only does the fungus deform leaves, it attacks the twigs, and if it spreads to branches or the trunk, the tree is likely a goner.

“Dogwood anthracnose (Discula destructiva) initially causes spotting and blotches on bracts and leaves and later moves into small twigs. Unless pruned out the infection will move into larger branches and eventually lead to cankers on the main trunk which can kill the entire tree,” the report said. That must be the destructiva part of the scientific name, I thought.

Pete Fife of Vine and Branch sprayed a fungicide of two native dogwoods to control dogwood anthracnose. The fungus disease could kill the tree if left untreated. (C) Jo Ellen Meyers Sharp

The lab recommends pruning out all dead wood and burn or bury material. Putting the wood out with the trash in Indianapolis will get it burned. Water during prolonged dry periods in summer to avoid drought stress, but avoid wetting the foliage. Spray with a fungicide to protect new growth. Trees with large trunk lesions or cankers can’t be saved and should be removed and burned or buried to reduce.

“We have had several calls and emails about dogwood recently but most of that has been related to cold damage in the northern part of the state,” said Tom Creswell, director of the lab. “I believe newly emerged leaves were stressed by a cold rainy period and the damage took a while to be noticed.”

The two dogwoods have been in this bed, heavily under planted with shade-tolerant perennials since 1999, and this is the first time I’ve had a problem. The tree affected is in more shade than its neighbor, which could account for its severity. I’ve hired a certified arborist to treat both trees with a fungicide this year and hope it is a one-time problem brought on by just the right environmental conditions.

Campaign promotes selling, planting native plants

The Indiana Native Plant and Wildflower Society and The Nature Conservancy have partnered to encourage gardeners to grow native plants. One of the ways it does this is by promoting retailers that sell the plants.

Grow Native is the statewide roll out of Go Green, Grow Native, a Monroe County initiative launched a few years ago. “We shortened the name to Grow Native and developed the website to simplify applying for the status and for sharing the Buy Native directory. We started the new version in February, and are now taking applications from around the state,” said Ellen Jacquart, an INPAWS member and former invasive plant specialist with TNC.

The idea is to recognize garden centers, nurseries and other retailers that carry native plants and to educate and encourage them to sell fewer invasive species. Retailers can sign up at for the program on two levels. A Basic member if a retailer who sells native plants. The Invasive Free retailer has agreed not to sell invasive plants, which comes with additional promotions, she said.

About 30 businesses are on the list, including two in Indianapolis – Cool Ponds and Mark M. Holeman Inc. Others listed from the area have one-time plant sales, such as INPAWS, Master Gardeners and the Indiana School for the Blind and Visually Impaired.

David Gorden, landscape architect and partner at Holeman, said he and the company have been long-time supporters of INPAWS and frequently feature native plants in their designs and installations. He finds customers are “more and more interested in native plants for their landscapes.”

Pawpaw flowers dangle amid redbuds on a spring day. (C) Jo Ellen Meyers Sharp

Although not a garden center, people can make appointments to find native plants or to have them ordered. For example, people may want the Indiana banana tree, or pawpaw (Asimina triloba), which can be hard to find, he said.

The free and voluntary program was an appealing way to start the conversation with plant sellers and educate them about the issue of invasive plants in horticulture, Jacquart said. Businesses at either level can display the Grow Native decals in their windows.

“More and more gardeners are buying native because of all the advantages these plants provide,” Jacquart said. “The Grow Native project helps put native plants in the hands of gardeners who want them.”