This year has been different for everyone in and out of the greenhouse industry. But trial garden managers have all faced their own sets of challenges.

Not every trail garden faced the same challenges. State-to-state and location-to-location, the ongoing coronavirus pandemic presented challenges for managers to plant, maintain and even access their gardens.

Take Michigan State University’s trail garden, managed by Kristen Getter and Daedre McGrath. Preventative measures put in place by MSU leadership limited staff and the time that the garden was accessible. That presented challenges not just for maintaining the garden over a long period time, but also for simple tasks such as watering plants on schedule.

“We were very concerned that we weren’t going to be able to do it,” Getter says. “Because the trials are so important to the industry, we decided to cancel some other things first because with limited staff, we just couldn’t do everything.”

“We just kept being persistent with our administration and making the case that this is really, really important,” she says. “They finally agreed. We came up with a good argument, especially considering that Spring Trials was canceled and such.”

“For me, on a week-to-week basis, we didn’t know the status of things,” McGrath adds. “At one point, we thought we might be shut down completely — no one going into the greenhouses. We had thought we might have to let everything die, but that turned into letting the plant sale stuff die and keeping the trial material alive. There were seeds I didn’t know if I’d be able to plant outside, so there were also concerns about getting things planted on time and not knowing if we’d ever get to the end result.”

Still, gardens around the country were able to push on and grow robust trial gardens. For Greenhouse Management’s compilation of trial garden results, managers from across the U.S. submitted what performed best in their region in the following eight categories: best drought-tolerant annual, best drought-tolerant perennial, best pollinator-friendly annual, best pollinator-friendly perennial, best heat-tolerant annual, best heat-tolerant perennial, best overall performance: annual and best overall performance: perennial. On the following pages, find a selection of the submitted results.

The rest — including results from Colorado State University, Mast Young Plants, Smith Gardens and the Gardens at Ball — are available here. All of the descriptions and photographs have been submitted by the various trial garden managers.

BEST OVERALL PERFORMANCE: ANNUALS

Southeast

Coleus ColorBlaze Pineapple Brandy (Proven Winners), Young’s Plant Farm

Bright chartreuse colored foliage on this coleus works in sun but also really brightens up a spot in the shade. Very late to flower so you can fully enjoy the foliage all summer long. Takes the heat and humidity of an Alabama garden.

Zinnia 20OS12 (All-America Selections), North Carolina State University

WOW, WOW, WOW! Uniform, well-branched plants are compact and covered, wall-to-wall, with yellow, orange and red flowers. The mix of flower colors and flower pattern are unique. This plant is a true showstopper. Everyone loved this zinnia!

Midwest

Begonia Florencio Orange (Syngenta Flowers), Plantpeddler

Absolute stunning flowering begonia that flowered from beginning of the summer until frost. Had a continual mass of bright orange flowers all season with very little care. Did very little deadheading on the basket, fertilized weekly and watered. It took care of itself.

Bracteantha ‘Granvia Gold’ (Suntory), Michigan State University

This gigantic strawflower has looked great all season and received lots of praise from our staff and visitors. It is extremely vigorous, heat tolerant, and mildew resistant. We can only hope Suntory releases more colors in the future!

Petunia Bee’s Knees (Ball Horticulture), Raker-Roberta’s Trial Gardens

Vivid yellow with constant blooming. Held up all summer without splitting, even after torrential downpours.

BEST OVERALL PERFORMANCE: PERENNIALS

Southeast

Echinacea ‘Kismet Raspberry’ (Terra Nova Nurseries), North Carolina State University

Clear raspberry-red colored flowers continuously blooming on sturdy upright stems are good for cuts or you can leave the seed heads for the birds. Low maintenance, and pollinators love these guys!

Midwest

Heuchera ‘Grande Amethyst’ (Terra Nova Nurseries), Michigan State University

This Heuchera received perfect marks all summer. With vigorous mounding growth of purple wavy leaves, this variety practically formed a groundcover by mid-summer of its first year in the ground.

Phlox LUMINARY ‘Opalescence’ (Proven Winners), Walter’s Gardens

‘Opalescence’ is one of two new introductions of Phlox paniculata in the Proven Winners perennial program. This variety is the gold standard for powdery mildew resistance and also has the darkest green foliage of any Phlox paniculata we’ve seen. The fragrant, light pink flowers have dark pink eyes and are produced in large panicles.

BEST DROUGHT-TOLERANT ANNUALS

Southeast

Celosia ‘Bikaver Red’ (HEM Genetics), Young’s Plant Farm

Celosia is a great drought-tolerant plant. ‘Bikaver Red’ is an easy to grow celosia that just gets better as the summer goes on. Bright red flowers on a deep red foliage plant — really stands out in the garden

Gaillardia ‘Heat It Up Yellow’ (Proven Winners), North Carolina State University

Compact, uniform mounds covered in clear, bright yellow flowers. Continuous bloomer with no deadheading necessary. Great low maintenance plant. Pollinators like it, too!

Midwest

Lantana Havana Sunset (Dümmen Orange), Plantpeddler

Was very impressed with the growth habit of this lantana along with the flower power during the hot, dry July we had. Came in color early, stayed in color all season, and never lost its color. The pink and yellow blossoms stood out among the rest of the lantana in the beds.

Gomphrena Ping Pong Purple Improved (Sakata), Raker-Roberta’s Trial Gardens

Looked good, even great as a cut flower, and also good as a dried flower.

BEST DROUGHT-TOLERANT PERENNIALS

Southeast

Veronica ‘Venture Blue’ (Terra Nova Nurseries), North Carolina State University

Compact, low growing plants that are covered in dark blue flowers. Continuous flowering spikes on sturdy upright stems. Low maintenance, easy to grow and no deadheading needed. Handles the heat well.

Midwest

Digitalis Camelot Lavender (Syngenta Flowers), Raker-Roberta’s Trial Gardens

First year planting. Still flowering into October. Series typically performs well.

Perovskia ‘Sage Advice’ (Proven Winners), Walter’s Gardens

This perennial is perfect for hot, dry climates, but performs well in a wide variety of environments. ‘Sage Advice’ has rich, lavender purple flowers that are a darker shade than other Perovskia to date. Compared to ‘Denim ‘n Lace’, this variety has darker flowers and calyces, broad (vs. dissected) foliage, and is slightly taller.

BEST POLLINATOR-FRIENDLY ANNUALS

Southeast

Cuphea Tiny Mice (Benary+), Young’s Plant Farm

Unique red and purple flowers that pollinators love. This cuphea has a nice, full growth habit with tons of flowers that the bees loved all summer long. Tiny Mice also looks good in combinations.

Salvia ‘White Flame’ (Ball FloraPlant), North Carolina State University

Easy, carefree growing plants that are very uniform in size. These plants are covered in white flowers that pollinators visit often. They have great heat tolerance, too.

Midwest

Lobularia Stream Lavender and White (Danziger), Plantpeddler

Lobularia is one of those flowering annuals that keeps on giving all season long. If you give it a little care, it will give you total flowering enjoyment all season. In addition, you can get a great crop of honey as a bonus. Bees love it! We had swarms of happy bees hovering over it throughout the season.

Salvia Bodacious Smokey Jazz (PlantHaven), Raker-Roberta’s Trial Gardens

Hummingbirds love this plant. The black caLyx with bright purple leaves and lighter green leaves really stand out.

Salvia ‘Lancelot’ (PanAmerican Seed), Michigan State University

Lancelot is a Salvia canariensis, which typically have a wild and wooly habit. This variety, however, has been tamed. This unique border plant will reach almost 4 feet high by the end of the season. It has silvery-white, fuzzy and aromatic leaves followed by lavender flowers, which appear mid-summer. Insect pollinators just love it!

BEST POLLINATOR-FRIENDLY PERENNIALS

Southeast

Echinacea Kismet Series (Terra Nova Nurseries), North Carolina State University

All colors — intense orange, red, white and raspberry — provide continuous flowering on sturdy upright stems that are good for cuts or you can leave the seed heads for the birds. Low maintenance, attractive flower colors and easy to grow. Makes coneflowers a gardener’s favorite!

Midwest

Allium ‘Serendipity’ (Walter’s Gardens), Michigan State University

Serendipity is in its second year of evaluation in our perennial trial. It is a sport off of the popular Allium ‘Millenium’, but with blue foliage. The clumps of drumstick-shaped flowers are very impressive en masse and are a favorite food source for honeybees and native pollinators alike.

Nepeta Whispurr Blue (Darwin Perennials), Raker-Roberta’s Trial Gardens

Bees love this one. Lots of flowers. My cat also really enjoyed this plant.

Origanum ‘Drops of Jupiter’, (Proven Winners), Walter’s Garden

Origanum ‘Drops of Jupiter’ is a new introduction to the Proven Winners perennial program. This ornamental herb has beautiful chartreuse foliage with mauve pink flowers appearing later in the summer. The purple calyces remain on the plant after the flowers drop, extending its appeal into fall. This plant is great in the landscape and in containers, and is an attractive pollinator plant for both bees and butterflies.

BEST HEAT-TOLERANT ANNUALS

Southeast

Helianthus Sunbelievable Golden Girl (Danziger), Young’s Plant Farm

This helianthus just got bigger and better during the summer heat. Features a shrub like growth habit that is absolutely full of bright, yellow sunflowers. Golden Girl was a showstopper in our summer garden!

Midwest

Bracteantha Granvia Gold (Suntory Flowers), Plantpeddler

The best bracteantha in the market by far. Large, long-lasting flowers on top of lust dark green foliage. Stunning in the gardens. Loved the hot summer weather in July and August in Iowa. There is also a new Pink in the series, but it’s hard to beat the mass of vivid gold flowers.

Lantana Bandana Gold (Syngenta Flowers), Raker-Roberta’s Trial Gardens

All the lantanas did well this summer. The Bandana series always performs and this one was full and robust all summer long.

BEST HEAT-TOLERANT PERENNIALS

Southeast

Penstemon ‘Dakota Verde’ (Terra Nova Nurseries), North Carolina State University

Glossy, green leaves provide long term interest. Flowers are a lavender/pink color; the showy dark seed heads that form after bloom are attractive. Can use both the flower and seed heads for cuts. Pollinators like these plants, a bonus!

Midwest

Echinacea Sombrero Rosada (Darwin Perennials), Raker-Roberta’s Trial Gardens

The Sombreros always look good. This one’s Pinkish Rose color stood out in our trial.

Kniphofia PYROMANIA ‘Backdraft’, (Proven Winners), Walter’s Gardens

The six colors of Kniphofia in the PYROMANIA Collection are tropical looking perennials but are hardy to zone 5b. ‘Backdraft’ has wide flower spikes that start out an intense reddish orange and open to a peachy yellow for a two-tone color effect. All members of the collection have excellent rebloom until late into the season and grass-like, textural foliage.