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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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July garden checklist

Indoors

  • For best selection, order spring-flowering bulbs for fall planting. Many bulb merchants will wait to ship the bulbs until closer to planting time, which usually is late fall and early winter. Photo courtesy Netherlands Flower Bulb Information Center

    For best selection, order spring-flowering bulbs for fall planting. Many bulb merchants will wait to ship the bulbs until closer to planting time, which usually is late fall and early winter. Photo courtesy Netherlands Flower Bulb Information Center

    Keep an eye on houseplants that have been set outdoors to make sure they are watered properly. Hot summer breezes can quickly dry them out.

  • Propagate houseplants by taking cuttings from vigorously growing plants. Root in moistened growing medium, such as perlite, vermiculite or soilless mixes. Keep moist, enclosed in plastic and out of direct sunlight until rooted. The amount of time it takes to root varies according to plant and growing conditions.

General landscape

  • Supplement rainfall to newly planted nursery stock, gardens and lawns if needed to supply 1 to 1 1/2 inches of water each week or 10 days.
  • Container-grown plants can be planted anytime, but make sure new stock is well watered.
  • Keep grass at 3 ½ to 4 inches tall to conserve moisture.
  • Don’t remove clippings from the lawn unless grass is excessively tall. Clippings return nutrients to the soil and do not contribute to thatch buildup.
  • Apply mulch around young plants and in flower and vegetable gardens to conserve soil moisture and control weeds. Do not allow mulch to touch stems or trunks.
  • Remove water sprouts (from trunk) and suckers (sprouts from roots) on fruit trees, including crabapples and other ornamental trees. See illustration below.
  • Illustration courtesy www.tlcfortrees.com

    Illustration courtesy www.tlcfortrees.com

    Pinch off faded rose blossoms and other flowers. Deadheading, or picking off the faded flowers of many perennials and annuals keeps them blooming longer and tidies up the plants.

  • To rejuvenate summer-stressed plants, cut annuals and perennials back by about one-half, water well and apply an application of water soluble fertilizer.

Vegetables and fruits

  • Start seeds of broccoli, cabbage, Brussels sprouts and ornamental kale and cabbage for late summer plantings and fall harvest.
  • Harvest tomatoes, squash, okra, peppers, beans and cucumbers frequently to encourage further production.
  • Complete succession planting of bush beans and sweet corn.
  • Standard sweet corn is at its peak for only a day or so. The super sweet corn maintains its peak quality longer. Harvest when silks begin to dry and kernels exude a milky, rather than watery or doughy juice when punctured.
  • Broccoli seedlings. Photo courtesy National Garden Bureau

    Broccoli seedlings. Photo courtesy National Garden Bureau

    Make sure potato tubers, carrot shoulders and onion bulbs are covered with soil to prevent development of green color and off flavors. Apply mulch to keep them covered.

  • Allow blossoms on newly planted strawberries to develop for a fall crop.
  • Prop up fruit tree branches that are loaded heavily with fruit.
  • Harvest raspberries when fully colored and easily separated from stem. After harvest, prune out fruiting canes.

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.

 

June garden checklist

Plants growing in containers, such as these at Sullivan Hardware & Garden near 71st and Keystone in Indianapolis, can be transplanted any time you can work the soil. (C) Jo Ellen Meyers Sharp

Plants growing in containers, such as these at Sullivan Hardware & Garden near 71st and Keystone in Indianapolis, can be transplanted any time you can work the soil. (C) Jo Ellen Meyers Sharp

Indoors

  • Houseplants will need more water and fertilizer during summer growing period.

General landscape

  • Prune spring-flowering shrubs within a month after blooms fade.
  • Supplement water as needed. Most newly planted stock needs an inch of water every week or 10 days. Established trees, shrubs and perennials can go several weeks without supplemental watering.
  • Remove faded blooms from peony, iris, delphiniums and other spring perennials.
  • Container-grown stock, including shrubs, trees, perennials and annuals, can be planted any time.
  • Continue planting gladiolus for successive blooms.

Vegetables and fruits

  • Discontinue harvest of asparagus and rhubarb in mid-June to allow foliage to develop and store food reserves for next year. Fertilize. Water when dry.
  • Blanch (exclude from light) cauliflower when heads are 2-inches in diameter. Tie leaves up over the developing heads.
Broccoli head ready for harvest. Photo courtesy Purdue University

Broccoli head ready for harvest. Photo courtesy Purdue University

  • Harvest spring plantings of broccoli, cabbage and peas.
  • Plan your Halloween pumpkin. Determine the days to harvest for particular cultivar and count backward to find the proper planting date.
  • Remove cold-season plants, such as radish, spinach and lettuce, as they bolt or form seed stalks.
  • Every week or 10 days, continue planting carrots, beans and sweet corn for successive harvests.
  • Do not be alarmed by June drop of tree fruit. It is a natural thinning process. If needed, help nature by thinning fruit to 6- to 8-inches apart and propping heavy branches.