Insights for some of the best Northeast perennials

New varieties are always exciting to look at in catalogs and dream about in your beds – but how they actually perform is another story.

Fortunately, trial gardens exist and do a lot of the heavy lifting for growers. Presenting “Right Plants, Right Place: Perennial Insights for the Northeastern U.S.” at the most recent Cultivate conference was Justin Wisniewski, general manager of Must Have Perennials. He originally joined the Aris organization as a trial gardener for Green Leaf Plants in Lancaster, PA, in spring 2016 – and that’s where these plant trials took place.

Green Leaf Plants has a one-acre garden in USDA Hardiness Zone 7A. They grow 535 varieties, from 32 different breeders, in their public garden. It’s a 50/50 mix of first- and second-year plantings.

“It usually takes about four to six years to really evaluate something, sometimes eight,” Wisniewski explained.

The gardens do three full ratings of their plantings each season, looking at overall quality, foliage, habit/uniformity and flower (if applicable), as well as doing periodic check-ins.

“We take a ‘set it and forget it’ approach,” Wisniewski said. “It lets us see how strong the genetics really are.”

First, a few notes: the Lancaster area has clay soils with poor drainage, and some varieties simply don’t do well in them.

These findings covered through the middle of August 2023. The weather conditions leading up to that point included winter 2022/23 with no snowfall; an early spring warm-up followed by dropping temperatures; near-drought conditions through early June 2023; and then “feast or famine” rainfall throughout July and August.

Ultimately, the raters came up with results of 30% good, 14% very good, 3% excellent and 3% top performers. The best of the best are detailed below.

Consistently Top Performers

These 10 varieties were rated excellent or above for two years. The notes were provided by Wisniewski.

Gaillardia Realflor® ‘Sunset Orange Ruffles’ (PlantHaven International) – Great; might spread a lot.
Geranium Blushing Turtle (Must Have Perennials®) – Can get tall in the shade.
Lavandula angustifolia Blue Spirit Purple Blue (Dummen Orange®) – Keep it dry.
Leucanthemum superbum ‘Becky’ (Walters Gardens) – Has staying power.
Nepeta faassenii Whispurr™ Blue (Darwin Perennials®) – Offers a few alternative species.
Rudbeckia American Gold Rush (Intrinsic Perennials) – Great cold hardiness.
Salvia nemorosa ‘Blue By You’ (Darwin Perennials) – Could be ‘May Night’ Salvia’s replacement.
Veronica longifolia ‘Blue Skywalker’ (Walters Gardens) – Performed well.
Veronica ‘Seaside’ (GardenChoice™) – Great staying power of flowers; a visitor favorite.
Veronica longifolia Skyward™ Pink (Darwin Perennials) – A great variety.

Nepeta ‘Chartreuse on the Loose.’ Photo courtesy of Walters Gardens

Top First Year Performers

The following 10 varieties were rated excellent or above in 2023:

Rudbeckia 2019 40 (AB Cultivars) – A visitor favorite with great color. Rudbeckias have been very consistent.
Echinacea hybrid Kismet™ ‘Raspberry’ (Terra Nova/ThinkPlants™) – Strong habit and color.
Dianthus American Pie® Bumbleberry Pie and Cherry Pie (PlantHaven International/Whetman) – Both exceptional performers.
Echinacea hybrid Double Scoop™ Watermelon Deluxe (Darwin Perennials) – Vibrant neon color; a visitor favorite.
Heuchera hybrid ‘Black Forest Cake’ (Terra Nova/ThinkPlants) – A new color combination.
Veronica longifolia Candela Pink (Dummen Orange) – Great for pollinators.
Nepeta ‘Chartreuse on the Loose’ (Walters Gardens) – “Knocked my socks off” – full bloom in March.
Leucanthemum maximum Sweet Daisy® Izabel (Dummen Orange) – Retains yellow color well.
Coreopsis grandiflora Solanna™ Sunset Bright (Danziger/ThinkPlants) – A high level performer.
Ocimum basilicum Herbalea® ‘Wild Magic’ – A beautiful dark basil.