Longwood Garden’s Captivating Landscape Combinations — From the Public’s Perspective

Longwood Garden's LogoWhen designing extraordinary combinations of plants, one must account for many plant attributes. The right combination, whether it resides in the landscape or within a container, demands a balanced mix of color and texture.

Attributes of a Stellar Combination
An impactful combination is one that displays complementary and contrasting colors. Darker foliage plants, such as Coleus ‘Dark Star,’ make small bright flowers pop or create dramatic color contrasts. Changes in texture tie everything together and keep one’s eye moving through the mix, shifting from fine to coarse textures. Pennisetum (fountain grass) and other tall grasses can give planting combinations beautiful movement and create a billowing effect as the seedheads sway in the wind.

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Plant size and architecture provide the framework for a combination. Large, mounding colocasia plants (elephant ears) can create a mountainous effect, while canna or cyperus can add significant stature. Designers must be careful, however, not to overuse large or fast-growing plants, as they can take over.  Sweet potato vine is one plant that can quickly consume a slower-growing neighbor. Designers should also consider bloom time and duration. Ideally, the combination should have plenty of interest from spring through fall.

The Combination Challenge
World-renowned Longwood Gardens in Kennett Square, PA, wanted to see what kinds of captivating plant combinations its expert staff could create. Since designers would likely vary in their opinions of the best combination, Longwood turned to its guests. For two summers, Longwood trialed 38 different planting combinations in its Trial Garden and provided ballots for the guests to vote for their favorites.

In 2015, Longwood trialed 26 different combinations. The following year, Longwood trialed 15 combinations, including the top three from 2015, to see if they could stand the test of time. Since this trial created a bit of friendly competition amongst the designers, Longwood established some rules for the challenge. Designers had to create combinations by selecting three to eight plants from a list of more than 160 garden plants. Longwood assigned each selected plant a percentage in terms of bed coverage and determined that designers also needed to randomly place plants in the bed to create true combinations, rather than create a design with sweeps and concentrated areas of certain plants. Finally, Longwood assigned names to all the combinations, such as Land of Fire and Ice, Breezy Cheezy, and Textural Tendencies, for voting purposes.

Gardeners planted the trial combinations in June and the plants were given a few days to settle in. Voting began thereafter and lasted until early October. Guests selected their three favorite combinations by assigned name. Longwood staff counted the votes on a weekly basis, tallying more than 7,000 ballots submitted over the course of two voting seasons.

And the Winner Is . . .

The top three winners from each year were:

3rd Place (2015): Green with Envy
Created by Maddie Maynor, Greenhouse Grower

Plant Species Common Name Percentage
Alternanthera  ‘Yellow’ Yellow Joseph’s Coat 10%
Angelonia angustifolia  ‘Serena Blue’ Angelonia ‘Serena Blue’ 15%
Cyperus  ‘King Tut’ Cyperus ‘King Tut’ 15%
Euphorbia ‘Diamond Delight’ Euphorbia ‘Diamond Delight’ 15%
Ipomoea batatus ‘Sweet Caroline Bewitched’  Sweet Potato Vine ‘Sweet Caroline Bewitched’ 5%
Scaevola ‘Blauer Facher’ Scaevola ‘Blauer Facher’ 15%
Solenostemon scutellarioides  ‘Dark Star’  Coleus ‘Dark Star’ 15%
Solenostemon scutellarioides ‘Under the Sea Gold Anemone’ Coleus ‘Under the Sea Gold Anemone’ 10%

2nd Place (2015) and 3rd Place (2016): Prairie Sunset
Created by Sam Hoadley, Senior Horticulturist

Plant Species Common Name Percentage
Agastache cana  ‘Sinning Sonoran Sunset’ Hyssops ‘Sinning Sonoran Sunset’ 5%
Agastache mexicana  ‘Kiegador  Acapulco Orange’ Hyssops ‘Kiegador Acapulco Orange’ 10%
Artemisia  ‘Powis Castle’ Wormwood, mugwort, A. ‘Powis Castle’ 10%
Carex flageliffera  ‘Toffee Twist’ Toffee Twist Hair Sedge 10%
Emilia coccinia   Scarlet Tasselflower 10%
Nassella tenuissima   Mexican Feather Grass 35%
Pennisetum villosum   Feathertop Fountain Grass 10%
Verbena bonariensis   Purpletop Vervain 10%

1st Place (2015): Hot Hot Hot!
Created by April Bevans, Senior Horticulturist

Plant Species Common Name Percentage
Canna ‘Mohawk’ Canna ‘Mohawk’ 10%
Colocasia esculenta ‘Elana’ Elephant Ear ‘Elana’ 10%
Ipomoea batatus ‘Sweet Caroline Sweetheart Light Green’ Sweet Potato Vine ‘Sweet Caroline Sweetheart Light Green’ 15%
Pelargonium ‘Cante Ros Caliente Rose’ Geranium ‘Cante Ros Caliente Rose’ 25%
Tagetes erecta ‘Deep Orange’ Marigold ‘Deep Orange’ 25%
Zinnia ‘Zowie Yellow Flame’ Zinnia ‘Zowie Yellow Flame’ 15%

2nd Place (2016): Opposites Attract
Created by April Bevans, Senior Horticulturist

Plant Species Common name Percentage
Angelonia angustifolia ‘Serena Blue’ Angelonia ‘Serena Blue’ 25%
Canna ‘Phasion Tropicanna’ Canna ‘Phasion Tropicanna’ 5%
Dahlia ‘Mystic Spirit’ Dahlia ‘Mystic Spirit’ 5%
Otacanthus azureus Brazilian Snapdragon 20%
Pennisetum setaceum ‘Rubrum’ Purple Fountain Grass 5%
Salvia guarantica ‘Kobalt’ Sage ‘Kobalt’ 10%
Zinnia marylandica ‘Zahara Double Fire’ Zinnia ‘Zahara Double Fire’ 30%

1st Place (2016): Little Jewel
Created by Julie Bodenstab, Continuing Education Associate; Susan Caldwell, Instructional Designer and Learning Techniques Manager and Susan Nichols, Registrar, Continuing Education

Plant Species Common Name Percentage
Colocasia esculenta  ‘Elana’  Elephant Ear ‘Elana’ 10%
Emilia coccinia   Scarlet Tasselflower 10%
Petunia x Calibrachoa ‘SupertCal Blue’ Petunia x Calibrachoa ‘SupertCal Blue’ 20%
Salvia guaranitica  ‘Kobalt’ Sage ‘Kobalt’ 25%
Solenostemon scutellarioides ‘Lime Time’ Coleus ‘Lime Time’ 15%
Verbena x hyb. ‘Lan Dareda Lanai Dark Red’ Verbena ‘Lanai Dark Red’ 20%