Announcing the 2020 GCA Plant of the Year

The 2020 Freeman Medal winner Geum triflorum, A Stellar North American Native Plant

Geum triflorum, commonly known as prairie smoke, has been named the 2020 Plant of the Year by The Garden Club of America (GCA). Annually, the GCA identifies a stellar North American native plant to receive The Montine McDaniel Freeman Medal: Plant of the Year. 

Prairie smoke, an exquisite herbaceous perennial, is an early bloomer on prairies and a great nectar source for native long-tongued bees and butterflies, as well as native bumblebees and sweat bees. Although prairie smoke is being challenged by taller, non-native plants in its native mesic prairie sites, it is readily adaptable to many other areas. Tolerant of poor soil, moderate drought, heat, and humidity, Geum triflorum can be grown in sun or partial shade and is suitable for cottage gardens, prairies, meadows, and perennial beds. It is not favored by deer or burrowing animals. Geum triflorum is hardy in USDA Hardiness Zones 3-7.

This medal was established in 1995 to highlight underutilized, but highly worthy, native trees, shrubs, groundcovers, vines, and perennials. The goal is to draw attention to select native plants, encourage their use in the landscape, and make them familiar to gardeners and more available in nurseries. The annual medal selection is carried out by a group of highly respected horticulturists from across the country. Woody and herbaceous plants are nominated in alternate years. The 2020 winners were selected from 23 herbaceous plants nominated by members of GCA clubs.          

Honorable Mention was awarded to Asarum canadense, wild ginger. This North American wild ginger, a shade-loving herbaceous perennial, colonizes to form a graceful ground cover that successfully competes with non-native plants. It is a food source for Battus philenor, pipevine swallowtail, is deer resistant, and unpalatable to other mammals. A low maintenance plant, it grows well in many different soil types. Asarum canadense is hardy in USDA Hardiness Zones 4-6. 

Honorable Mention was also awarded to Penstemon strictus, Rocky Mountain penstemon. This native penstemon is a prolific pollinator magnet, attracting butterflies, moths, and native bees. It is adaptable to both wild sites and garden settings and thrives in sandy loam, rocky soil, and even clay soil. Penstemon strictus is a vigorous, low maintenance perennial suitable for growing in sun or partial shade. Penstemon strictus is hardy in USDA Hardiness Zones 3-8.

Special Recognition was awarded to Zamia integrifolia, coontie, a native of the southeastern United States (GA and FL) and parts of the West Indies. Z. integrifolia is the only cycad native to the United States. Coontie was harvested almost to extinction during WWI, because its starchy roots were made into a mold-resistant flour that was sent overseas. Along with its comeback came the rediscovery of Eumaeus atala, Atala butterfly, which uses coontie as its host plant. Zamia integrifolia is hardy in USDA Hardiness Zones 8-11.

2020 PHS Gold Medal Plants Announced

The Pennsylvania Horticultural Society has selected the 2020 Gold Medal Plants, recognizing exceptional plants for both home gardeners and professional landscapers. The PHS Gold Medal Plant Program spotlights outstanding trees, shrubs, vines, and perennials for gardens in the mid-Atlantic region (growing zones 5 to 7). Plants are chosen for their beauty, hardiness, and ecological benefits.

“PHS has incorporated these plants in many of the gardens and landscapes that we manage and can recommend them as reliable plants for our region’s growing conditions. Many promote pollinators and birds in the garden and are deer resistant,” said Julia Thomé, Director of Gardener Engagement at PHS. “A selection of Gold Medal Plants will be on display at the 2020 Flower Show, and PHS staff and volunteers are available to talk with you about these and other plant choices for the home garden.”

Since 1979, the Gold Medal Plant program has honored and promoted plants of outstanding merit. The program was originally conceived by noted nurseryman Dr. J. Franklin Styer, who realized homeowners and gardeners needed to learn about superior woody plants for their landscapes. Five years ago, PHS began including perennial plants in addition to woody plants, in its selections. Plants are nominated from submissions by home gardeners, garden designers, horticulturists, landscape architects, nursery owners, and propagators.

Once nominated, plants are reviewed by a committee of expert horticulturists led by Chairman Steve Mostardi of Mostardi Nursery. Through in-person discussions and an online rating system, the Gold Medal Plant Committee selects the winning plants, on a yearly basis, that meet the rigorous criteria for excellence set forth by PHS. Gardeners who acquire a Gold Medal designated plant can be assured the plant will exhibit standards of excellence for pest and disease resistance, as well as ease of growing when planted and maintained appropriately. To view a searchable database of all past and present winners, please visit phsonline.org/programs/gold-medal-plants/.

2020 PHS Gold Medal Plants
Aronia melanocarpa “Viking” | Black Chokeberry
Flowers bloom in spring, followed by showy black fruits and red fall foliage. Fruits are edible when cooked into jams, salsa, or baked goods. Plant in combination with Virginia bluebells, Bowman’s root and/or short-toothed mountain mint. Can be planted in mass as a screen. Deciduous shrub; height 3-6’; zones 3-8.

Carpinus caroliniana | American Hornbeam (aka Ironwood, Musclewood)
Small size understory tree, ideal for residential sites. Catkins in March give way to yellow nutlets in late summer. Yellow-orange fall foliage. Steel gray bark provides winter interest. Plant in combination with native viburnums, grasses, and/or sedges. Deciduous tree; height 20-30’; slow growing, zones 3-9.

Coreopsis verticillata ‘Zagreb’ | Threadleaf Coreopsis
Bright yellow flowers, compact and upright, easy to grow in-ground or containers. Reblooms if sheared mid-summer. Great in combination with evergreen shrubs, Little Bluestem ornamental grass, native butterfly weed, and/or veronica. Herbaceous perennial; height 12-18”; zones 3-9.

Geranium X cantabrigiense ‘Biokovo’ | Cranesbill Geranium
Low growing and compact; will spread slowly as a groundcover. White flowers tinged with pink in spring. Plant in combination with a variety of bulbs such as daffodils or Allium ‘Summer Beauty,’ lady’s mantle, and/or fall blooming toad lilies. Herbaceous perennial; height 10-12”; zones 5-8.

Hydrangea arborescens ‘Haas’ Halo’ | Smooth Hydrangea
Large lacecap flowers, blue-green foliage. Spent flowers provide winter interest. Drought resistant once established. Plant in combination with the ninebark shrubs, Siberian bugloss, leadwort, Jacob’s ladder, smooth aster and/or reed grass. Deciduous, woody shrub; height approx. 4’; zones 3-9.

Perovskia atriplicifolia ‘Little Spire’ | Russian Sage, Little Spire
Compact and erect sub-shrub, drought tolerant. Striking light blue to violet color flowers. Aromatic silvery foliage. Great in combination with purple coneflowers, phlox ‘Jeana,’ sneezeweed, betony, and/or Foerster’s feather reed grass. Woody perennial; height 2-3’; zones 5-9.

Come Out of Your Cave; The winter garden is full of promise and productivity.

Once the usual fall garden tasks are addressed — leaf raking, bulb planting, clearing of spent annuals — the yard warrior and avid gardener alike retreat indoors for the long winter. Take a moment to read this article written by Adrian Higgins in the Washington Post this week about the period between now and March that offers a chance to take charge of the garden outside the demands of the growing season in a productively unhurried way.

Garden of Solace

Take a moment to read this touching essay written by Margo Rabb in the New York Times this week about 25-year-old grief and a garden we have all madly fallen in love with.

Margo Rabb is an acclaimed novelist whose debut, Cures for Heartbreak, was hailed by critics and young readers alike. Her essays and short stories have appeared in the New York Times, the Atlantic, the Rumpus, Zoetrope: All-Story, Seventeen, Best New American Voices, New Stories from the South, and One Story, and have been broadcast on NPR. Margo grew up in Queens, New York, and has lived in Texas, Arizona, and the Midwest; she now lives in Philadelphia with her husband and two children.

Remember closing day for Chanticleer is fast approaching. The garden is open 10:00 a.m. to 5:00 p.m. Wednesday through Sunday. The garden is also open on Friday evenings until 8:00 p.m. from May through Labor Day. Chanticleer will remain open until Sunday, November 3rd, 2019

Fighting Boxwood Fungal Infections and Pests

Boxwood Blight

While most news continues to be bad, there is some good news in the fight against this devastating disease. As with all fungal diseases, boxwood blight is almost impossible to eradicate once in plants or soil; it can survive for five years or more. It was first noticed in Europe in the 1990s and eventually made its way across the Atlantic to begin devastating boxwood collections in North America. According to Purdue University’s College of Agriculture.

Boxwood Blight is a disease caused by the fungus Cylindrocladium buxicola. The disease has been prevalent in Europe for over 20 years, and made its way to the United States in 2011. First found in North Carolina, it has since spread along the east coast and continues to move across the states each year. Fungicides may prevent infections in uninfected plants. However, spraying already blighted plants is not only ineffective but expensive and harmful to the environment.

Common, and particularly English boxwood (Buxus sempervirens and B. sempervirens ‘Suffruiticosa’), are especially susceptible to boxwood blight. Some varieties, which are known to be more tolerant than others, are being studied, propagated, and hybridized. NewGenTM, a hybrid Buxus, will be introduced in the nursery trade in 2020. For established collections, do everything you can to prevent fungal spores from coming in contact with your plantings. While not wind-borne, sticky spores may move short distances in the air. Spores can come in on contaminated boxwood or other susceptible plants (pachysandra, sweet box), as well as infected holiday boxwood greenery. Pruning tools, spray hoses, clothing, shoes, and wildlife also spread the disease.

Boxwood Blight’s most characteristic symptoms include brown/black, circular leaf spots that lead to defoliation, as well as dark black streaks on the stems of the infected plant. It is a sticky pathogen that moves through splashing water, plant to plant contact, equipment, or in debris. The optimal conditions for this pathogen include damp areas with little air movement between around 70-75 F (21-23 C). Unfortunately this pathogen can survive for long periods of time in plant debris. There is no known cure at the moment, but there are lots of tips on prevention and management.

Boxwood Leafminer

Boxwood Leafminer (Monarthropalpus flavus) is one of the most destructive boxwood insect pests. First found in 1910, they can now be found anywhere boxwood grow in the United States. The eggs of this fly are laid inside the leaf where the larvae develop and feed on the tissue. This feeding results in blotchy, blistered leaves that swell, discolor, and can prematurely defoliate. The small, orange, mosquito-like fly emerge in late April or early May (in Virginia) and spend about 2 week mating and laying eggs. The larvae are the most destructive to the boxwood plant and they can feed from June through the early fall. It’s been reported in 20 US states, three Canadian provinces, throughout most of Europe, New Zealand, and the Republic of Georgia.

NEW BUXUS CULTIVARS

Cultivar: Buxus NewGen Freedom® ‘SB300’ Zone: 5-8

Growth Rate: Fast, 3 to 6 inches per year Sun Exposure: Sun, part sun, shade

NewGen Freedom® is a relatively vigorous, rounded cultivar that is slightly taller than wide. It has beautiful glossy medium green foliage. Its habit is more uniform and tighter than ‘Wintergreen’ or ‘Winter Gem’ thus making it an excellent choice for many formal and residential landscapes. Deer resistant! NewGen Freedom® should be pruned each year in late winter to early spring. If not pruned, the plant will tend to open up in the center, especially in spring when new foliage is wet and young. NewGen Freedom® is very resistant to boxwood leafminer and very tolerant of boxwood blight. It has very few disease or pest issues when planted and cared for properly. NewGen Freedom® is an excellent boxwood. It was selected due to its high tolerance of boxwood blight and resistance to boxwood leafminer. Its vigor helps it create an attractive plant quicker than many cultivars but it also makes annual pruning a must. With annual pruning, this plant makes a fabulous specimen.

Uses: Medium specimen, medium hedge, foundation plant

Substitutes: ‘Wintergreen,’ ‘Winter Gem,’ ‘Jim Stauffer,’ ‘Green Mountain’

Size:      15 years (3.5’ Tall and 3.5’ Wide) 25 years (5’ Tall and 5’ Wide)

Cultivar: Buxus NewGen Independence® ‘SB108’ PP28888 Zone: 5b-8 with continued testing underway

Growth Rate: Medium, 2 to 4 inches per year Exposure: sun, part sun, shade

NewGen Independence® is a very deep green medium sized cultivar that holds excellent color throughout the winter. It has a rounded habit that is nearly as tall as wide. NewGen Independence® can be used in formal plantings where a medium sized round plant is desired. Would be a replacement for Buxus sempervirens ‘Suffruticosa’ (English Boxwood) for foundational plantings. Branching structure is very strong allowing it to withstand most moderate to heavy snow loads. Deer resistant. NewGen Independence® should be pruned lightly in late winter to early spring to maintain uniform shape. It is not uncommon for fall frosts to burn new growth that occurred in the late summer or fall. These burned shoots can be removed in late fall after first freeze or in late winter/early spring depending on the gardener’s preference.

More information about Boxwood Blight can found in the Summer 2019 Issue of GCA’s The Real Dirt