Who remembers when ‘Palace Purple’ was one of the hottest perennials in the market? It was the heuchera I planted in my new garden 30 years ago. I liked its color and valued its landscape utility but quickly pushed it aside when a real purple-leaved cultivar came along. After a few years of growing the new one, I realized that although ‘Palace Purple’ (Heuchera villosa ‘Palace Purple’) might not have the best leaf color compared to some of the newer cultivars, it was reliable. For as long as I can remember, their unreliability has made heucheras the punching bag of perennials. I’ve taken a swing or two myself.
Our trial at the Chicago Botanic Garden in the mid-1990s was a reaction to the fast-paced introduction of new cultivars. That trial yielded some good results, which I won’t rehash here since it was over 20 years ago. Instead, I want to highlight heucheras that we’ve evaluated in the past five years, along with a few exceptional, not-as-new cultivars I cannot resist still talking about. Within this trial group I was interested only in selections with breeding related to H. richardsonii and H. villosa because of their vigor and hardiness, but that’s not to say their ornamental variations weren’t important too.
Achieve the greatest heuchera success:
At a Glance
Name: Heuchera spp. and cvs.
Conditions: Full sun to partial shade; moist, well-drained, fertile soil
Native range: North America
Care and propagation: Prune unsightly foliage as needed; replant any frost-heaved plants, and divide in spring
Pests and diseases: Rust, fungal and bacterial leaf spotting, nematodes, slugs, and possible rabbit and deer browsing (but rare)
Pollinator-friendly: Bees, butterflies, hummingbirds
Foliage variation and adaptability set them apart
Heucheras come in tantalizing leaf colors—paprika, cinnamon, amber, peach, grape, plum, and chartreuse; some display a mix of colors at once or are simply green. Leaves and veins are often blushed, etched, or overlaid with red, burgundy, or silver. Leaf size, shape, and texture are variable, and leaves may be flattened, cupped, crinkled, or ruffled. But don’t forget the flowers—they offer color and movement and often complement the foliage nicely. Most floral color comes from the calyx; the petals are usually insignificant or absent. Airy clusters of tiny flowers are held on wiry stems above the foliage, attracting bees and butterflies in late spring and summer.
Heucheras in our previous trials have been grown in light shade, partial sun, and full sun; surprisingly, many plants excelled in sunny sites. The darker the leaf color, the better they looked. Yellow and peachy foliage burned up or off-colored horribly. Our latest trial—started in May 2022—is in a new evaluation garden that provides the heucheras with only limited shade for part of the day. Most plants have adapted well to the sunnier conditions, but the yellow-or peach-colored heucheras were stressed in the heat of the season.
The Chicago Botanic Garden has trialed 198 heucheras since 1995. Besides observing their ornamental traits, we monitored the plants to see how well they grew and adapted to environmental and soil conditions. We also kept a close eye on any disease or pest problems, and we assessed plant injuries and losses over winter.
How long: Minimum 4 years
Conditions: Full sun to partial shade; alkaline, clay-loam soil or sandy loam soil
Care: We provided minimal care, allowing the plants to thrive or fail under natural conditions.
Top Performers Offer a Cornucopia of Colors
I’d like to say that no heucheras were harmed in the writing of this story, but we’ve killed a lot of plants to get here! Someday I’ll do the math to figure out how many years each of the nearly 200 heucheras thrived during its trial period. My gut feeling is that it is not a large number. That said, I keep an open mind when a heuchera enters the trials and am always hopeful for success, even for the peachy ones. The following selections completed the full four-year trial and actually thrived throughout our evaluations.
‘Silver Gumdrop’ (H. ‘Silver Gumdrop’) made my recommendation list early—two years before it finished its trial in 2021—because of its beauty and strong habit. Leaves are purple early on and then gradually turn silver with purple undertones and dark venation. A blush of purple sticks around on the newest leaves but fades away when the stunning pink-purple flowers open in late spring. ‘Silver Gumdrop’ is a prolific bloomer, so deadheading makes for a tidier plant and maximizes the foliar display later in the season. Leaves flush purple again in fall and hold their color through winter, although desiccated foliage may obscure the show. ‘Silver Gumdrop’ was planted in an inhospitable site—dry, cracked, clay soil and full-sun exposure—and still it excelled. In the hottest, driest times, however, some scorching marred the bright foliage. A little afternoon shade is best.
Given the wonderful colors available, green-leaved heucheras often get overlooked. To be fair, describing ‘Carnival Cocomint’ (H. ‘Carnival Cocomint’) as green waters down the distinctive color stages. Young leaves are green with a central blotch of burgundy spreading out from the veins. Color recedes to the veins only as a silver overlay develops, accentuating a ribbon of green along the margins and finally turning silvery light green. Tiny hot-pink petals nestle in yellow-green calyces in late spring. ‘Carnival Cocomint’ is a prolific bloomer, with scores of tall flower stems rising 20 inches above robust leafy mounds. Plants in the Carnival series have H. villosa parentage, which gives them better tolerance to heat and humidity.
Having been evaluated from 2005 to 2011, ‘Color Dream’ (H. ‘Color Dream’) is the oldest cultivar in the mix—but it still ranks among the best from any of our trials, and for years it was the only newer heuchera I recommended. The silver leaves are etched with purple veins early and age to silvery green with dusky green veins; new leaves are flushed with purple for a short time, and the undersides are purple. Small, greenish-white petals peek out from purple calyces that match the flower scapes and play off the early purple accents. ‘Color Dream’ was a strong bloomer but took a few years to push up significant flowers. The compact habit nearly doubles in height with the flower stalks in summer. Aside from being attractive, plants were healthy and grew vigorously in bad soil and midday sun. It was gratifying to see that ‘Color Dream’ was also one of the top-performing silver-leaved cultivars in Mt. Cuba Center’s 2012–2014 trials.
Predicting my favorite cultivar should have been easy; I love dark purple–leaved heucheras, and there are a few great ones in the current trial. But from the start, ‘Carnival Watermelon’ (H. ‘Carnival Watermelon’) captured my imagination. Its large leaves are a lovely mingling of orange-red, pink, and peach hues with magenta undersides. As spring turns to summer, leaves lighten to green overlaid with silver and flushed with soft hints of the earlier colors. The dramatic color show is made more so by the bold plant size. The tall bronze flower stems echo the colorful leaves and hold loose clusters of creamy white and pink flowers.
The fate of cultivars in hyper-bred genera such as Heuchera is on my mind a lot. How many new introductions is too many at one time, and how many cultivars can survive the evolving market to have a lasting impact? ‘Cherry Cola’ (H. ‘Cherry Cola’) was one of my favorites from 2011 to 2014, which means it may be harder to find now. I loved its vivid vermilion leaves so much that I made a place for it in my garden. It was a brilliant companion to ‘Aureola’ Japanese forest grass (Hakonechloa macra ‘Aureola’, Zones 5–9) for a few years before the sprawling stems of a nonclimbing clematis (Clematis ‘Mrs. Robert Brydon’, Zones 4–9) smothered it. I tried to recreate the magic with several less-satisfying look-a-likes—but that turned out to be like grabbing Mr. Pibb because Dr. Pepper is sold out, so I finally ordered it. We grew ‘Cherry Cola’ in full sun, and its dark red leaves turned a flaming bright red-orange by midsummer. It was lovely in any hue, and doubly so because the leaves, floral stems, and flowers are all the same beautiful color.
My notes repeatedly described ‘Wildberry’ (H. ‘Wildberry’) as luminous, which is a dubious description for a plant with deep purple leaves—except that it is true; the crinkled surface of the glossy leaves reflects light like the facets of a gemstone. The color was strongest in spring and fall, but the color held up even in hot weather; a silvery shadow in high summer mutes the intensity of the purple a bit. Rose-pink flowers top dark stems nearly a foot above the plant and complement the foliage nicely. ‘Wildberry’ is my go-to now when recommending a reliable, beautiful, dark-leaved heuchera. We are keen to see how ‘Frosted Berry’ (H. ‘Frosted Berry’), a silver-leaved sport of ‘Wildberry’, measures up.
The Newest Selections Rival the Standards
Even though some heucheras in our trials have been under evaluation for only two growing seasons, a few cultivars are already standing out from the crowd. Keep your eyes peeled for the following selections, which are wowing us with their performance.
1. ‘Ball Gown’
The vibrant sunny yellow and chartreuse foliage of ‘Ball Gown’ (H. ‘Ball Gown’) is off the charts. In our garden, it is the perfect complement to common ajuga (Ajuga genevensis, Zones 3–9), which is covered in dark purple-blue flowers in May when ‘Ball Gown’ is glowing. Green is the predominant color in summer, but the newest leaves are always bright yellow. The creamy yellow flowers feel like an afterthought; they disappear against the brighter leaves and so far have not been plentiful. The robust habit of ‘Ball Gown’ is amplified by its large, ruffled leaves. Protection from strong sun is best to reduce leaf scorch, which can turn ugly fast.
2. ‘Toffee Tart’
It is easy to let preferences sway objectivity; leaf color is where I had to check myself in this trial. Appreciating the earth tones was not as natural to me as loving the deep purples and sultry reds, so it took a bit more time to see the real beauty of ‘Toffee Tart’ (H. ‘Toffee Tart’). But I got there! The caramel-colored leaves of spring turn ginger and amber in summer. While they were touted as having a silvery overlay, I did not see it. As leaves twist in the wind, light purple undersides are revealed and complement each of the color stages. Half of our plants were shaded from the afternoon sun, while others took the brunt of its heat and light, and it showed. These softer colors benefit from shade or protection from the western sun.
3. Northern Exposure™ Black
There is a lot to be said for the Northern Exposure™ Collection—strong habits, large leaves, great leaf colors, and cold-hardiness. The parentage of these plants includes the northern species, H. richardsonii—native to a large swath of the midwestern United States and much of Canada, including the Northwest Territories. Northern Exposure™ Black, Lime, and Purple are in the trials, but there are also silver, red, and amber selections. Northern Exposure™ Black (H. ‘TNHEUEB’) features glossy, black-burgundy leaves and pink flowers on tall stems. It is truly a beautiful plant, and it has been a strong performer as well. In its second summer the leafy mounds were decent in size, but the large ruffled leaves (5 inches wide) made the plants appear to be much bigger.
4. ‘Black Forest Cake’
‘Black Forest Cake’ (H. ‘Black Forest Cake’) makes me swoon. The glossy, dark purple leaves look almost black and are reminiscent of ‘Obsidian’ (H. ‘Obsidian’), a longtime favorite of mine. But unlike ‘Obsidian’, it has fabulous bright cherry-red flowers that, at 3/8 inch wide, are substantial by heuchera standards. These two intense colors taken together are almost lurid—in a good way—and are not an imitation of another heuchera. The plants so far are slightly bigger than expected. I can picture ‘Black Forest Cake’ in at least three spots in my tiny garden; I’m not sure I have the strength to resist.
5. ‘Carnival Cinnamon Stick’
On a hot day last July, the brick-red to copper-orange leaves of ‘Carnival Cinnamon Stick’ (H. ‘Carnival Cinnamon Stick’) blew me away. The intensity of the color was a surprise given the softer copper tones earlier in spring. From spring to fall, the ever-changing color show is a pleasing mix of red, orange, copper, and rusty brown. The rosy flowers, on bright red stems to 18 inches tall, are not yet plentiful on our plants but are a nice touch. ‘Carnival Cinnamon Stick’ makes a small mound compared to the robust cultivars in this series. I’m allowed to have more than one favorite, right?
6. ‘Big Top Caramel Apple’
My penchant for caramel-colored heucheras is growing thanks to ‘Big Top Caramel Apple’ (H. ‘Big Top Caramel Apple’). New leaves emerge soft red-burgundy, then fade to a pinkish hue and finally to light caramel. Older leaves are green or chartreuse; too much sunlight in our garden probably played a part in that. And the leaves are huge—up to 6 inches across—amping up the color and texture. Autumn brings a revival of the spring tones with red-burgundy and caramel accenting chartreuse and light green. By happenstance, ‘Big Top Caramel Apple’ is planted next to ‘Carnival Burgundy Blast’ (H. ‘Carnival Burgundy Blast’), and the color combination in spring is brilliant.
Chicago Botanic Garden Heuchera Trial Results
Richard Hawke is an expert plantsman and the director of ornamental plant research at the Chicago Botanic Garden in Glencoe, Illinois.