The following article is part of a series geared toward entry-level gardeners. For deep dives into a variety of perennials that we have sold over the decades, visit our archive of in-depth perennial articles written by Tony Avent, Dr. Patrick McMillan, and other Plant Delights and JLBG experts. We also have transcripts of our Gardening Unplugged videos, recorded during our Open Nursery and Garden Days, that have great information for gardeners of all experience levels.
North Carolina, with its diverse landscapes and temperate climate, has long been a haven for passionate gardeners seeking unique and striking plant varieties. While the mention of agaves often conjures images of arid desert landscapes, these succulent wonders are far more versatile than one might imagine. Contrary to popular belief, some agave species exhibit exceptional cold-hardiness, making them ideal choices for adventurous gardeners in Zone 7b. In this article, we delve into the world of cold-hardy agave, exploring their resilience and the stunning beauty they add to the Carolina landscape.
While the varieties listed below have proven to he cold-hardy for us, proper site selection and planning is necessary to improve the chances of success. Here are Plant Delights, we use a mix of soil, compost, and perma-till (a grey slate product available at many nurseries) and plant our agave on raised berms with good drainage. Planting an evergreen shrub on the north side of your agave also helps absorb excess water and prevent root-rot during the winter.
At Plant Delights Nursery at Juniper Level Botanic Garden, we have conducted outdoor trials of literally thousands of agave clones over the years. Many are hybrids or crosses that we have propogated and introduced for sale to the public.
Top 10 cold-hardy agaves that thrive in Zone 7b
Agave ovatifolia 'Cameo' is a 2023 introduction from Plant Delights/JLBG, showcasing a muted edge selection of Agave ovatifolia 'Vanzie.' The rosettes reach an impressive size of 4 feet tall and 7 feet wide, boasting corrugated blue leaves with a lime green border. Remarkably, the variegated form exhibits the same winter hardiness as the typical non-variegated Agave 'Vanzie.' This captivating agave variety promises to bring a touch of elegance and uniqueness to any garden setting, making it a sought-after addition for horticultural enthusiasts.
2. Agave parryi 'Border Guard'
Agave parryi 'Border Guard,' a 2021 introduction from Plant Delights/JLBG, is a unique discovery, featuring a muted lime green-edged sport of Agave parryi 'J.C. Raulston.' While it is expected to reach a mature size of 2 feet tall and 3 feet wide, this will take several years to achieve. To ensure winter hardiness when grown outdoors in the ground, providing perfect drainage is essential. This intriguing agave promises to add a distinctive touch to any garden, captivating viewers with its beautiful coloration and growth pattern.
3. Agave x amourifolia 'Twisted Tongue'
Agave x amourifolia 'Twisted Tongue,' a 2018 introduction from Plant Delights/JLBG, represents a fascinating blend of agave genes. Created in 2016, this cross includes Agave americana, Agave asperrima, Agave gentryi, Agave lophantha, and Agave ovatifolia, promising a truly remarkable seed strain. While the mature size is yet to be determined, estimates suggest the rosettes will reach approximately 3 feet tall and 5 feet wide. The leaves, uniquely arched in structure, range in color from green to bluish green, often displaying a muted central yellow stripe. The leaf edges are adorned with striking black/red teeth resembling steak knives. This diverse combination leads us to believe that Agave x amourifolia 'Twisted Tongue' will mature as one of the most exceptional century plants in any garden. Keep in mind that each seed-grown plant will exhibit slight variations, adding to its allure and uniqueness.
4. Agave asperrima
Agave asperrima, native to Southwestern Texas and Northern Mexico, thrives at elevations between 1,500' to 6,000'. The highland forms are winter hardy, while the lowland collections are not. At the JC Raulston Arboretum, a winter hardy form flowered, allowing the growth of seedlings for offering. This variety features 3' long, thick, silver-blue leaves with a sandpapery texture on both sides, likely belonging to Agave asperrima ssp. asperrima. Each rosette, 3' tall x 5' wide, forms a charming, fast offsetting clump. Plant it in a dry winter site as Agave asperrima is sensitive to winter moisture. It flowers in approximately 15 years, producing a beautiful 15-20' tall spike adorned with bright yellow, panicled flowers.
5. Agave bracteosa 'Stingray'
This variety of Agave bracteosa is a 2020 Plant Delights/JLBG introduction and a remarkable variegated form created by plantsman Hans Hansen from a mutation on the cultivar Agave bracteosa 'Calamar.' This stunning agave forms an octopus-like rosette with narrow, elegantly arching, spine-free leaves, each adorned with a luscious, wide creamy-yellow stripe. The addition of this border to the leaves is akin to adding icing to an already delicious cake. After ten years of growth, the clumps of Agave bracteosa 'Stingray' reach an impressive size of 18 inches tall and 3 feet wide, showcasing the plant's remarkable vigor and allure.
6. Agave lophantha 'Goldfinger'
Agave lophantha 'Goldfinger' is a 2023 introduction from Plant Delights/JLBG, selected from seeds in 2010. This exceptional variety resembles typical Agave lophantha until cold weather arrives, revealing a dazzling transformation as the top half of each leaf turns brilliant gold. In the offsetting patch, each rosette reaches a compact size of 18 inches in height and spreads 3 feet wide. With its distinctive beauty, Agave 'Goldfinger' has captured the hearts of horticultural enthusiasts and is sure to form a special bond with all who admire it.
7. Agave x loferox 'A Step Above'
Agave x loferox 'A Step Above' is the 2023 introduction from Plant Delights/JLBG, representing the F2 generation of Agave 'Stairway to Heaven'. While sharing the same genetics as its parent, Agave lophantha x Agave x pseudoferox 'Logan Calhoun', this second-generation hybrid showcases wider leaves and more prominent central banding. The rosettes, each unique, reach an average height of 3 feet and spread 4-5 feet wide, with dark green leaves measuring 3 inches wide and 3 feet long. Impressive cold tolerance is demonstrated, with virtually no damage observed at 7 degrees F. Notably, several plants have remarkably flowered just six years from seed sowing, displaying 20-foot-tall scapes that blend characteristics of Agave x pseudoferox and Agave lophantha. The flower's allure is undeniable, attracting ants, bees, hummingbirds, and adventurous agave breeders equipped with ladders.
8. Agave x protifolia 'Emerald Giants'
This extraordinary 2020 Plant Delights/JLBG introduction is a stunning agave hybrid created by our former adjunct researcher and agave specialist, Mike Papay. This exceptional hybrid was born from the cross of Agave ovatifolia and Agave x protamericana 'Saltillo,' resulting in a truly magnificent plant. Standing as the largest of our seedlings, one of these beauties has thrived in the ground since August 2018 and already reaches an impressive size of 3 feet in height and 5 feet in width. With its robust growth, we anticipate these remarkable agaves could effortlessly reach a height of 5 feet and a width of 10 feet or even larger. The leaves boast an alluring glossy green hue and are exceptionally wide, adorned with large marginal teeth and gracefully upturned leaf tips. Several have been thoughtfully planted in our gardens for potential future clonal selections, a process that may take 5-10 years to fully develop. However, due to the limited supply of these amazing seedlings, acquiring 'Emerald Giants' is a rare and exclusive opportunity. Don't miss the chance to witness the magnificence of this outstanding agave hybrid in your own garden.
9. Agave x pseudoferox 'Green Goblet'
Agave x pseudoferox 'Green Goblet' is a rare and extraordinary Yucca Do selection found in northern Mexico, near the Sierra Chiquita Mountains. Among a population of blue-hued Agave x pseudoferox, this clone stands out with its distinct dark green leaves, adorned with a delicate blue dusting at the leaf base, creating a breathtaking and rare sight. At maturity, 'Green Goblet' forms a massive clump, reaching an impressive height of 5 feet and spreading magnificently to 9 feet wide. Thriving in various climates, this remarkable agave withstands temperatures as low as single digits, provided it has good winter drainage. Adding to its allure, a mature specimen bloomed in 2011, featuring a stunning 25-foot tall flower stalk adorned with yellow flowers, attracting enchanting hummingbirds. As a rare gem, Agave 'Green Goblet' brings unique beauty and thriving nature to any landscape, making it an enchanting addition to your garden.
10. Agave victoriae-reginae 'Porcupine'
Agave victoriae-reginae 'Porcupine' is an exquisite clonal variety known for its flawless symmetry and stunning white leaf markings. Unlike offsetting agaves, this unique selection maintains a compact and distinct appearance. While famously slow-growing, taking 5 to 10 years to reach a basketball-sized clump, 'Porcupine' is well worth the wait, becoming an elegant centerpiece in any garden. To thrive in rainy climates, it requires good winter drainage and a slightly sloped planting site. When it finally blooms, the 15-foot-tall flower stalks, adorned with tightly held yellow flowers, attract enchanting hummingbirds, adding natural splendor to any outdoor sanctuary. Embrace the beauty and allure of 'Porcupine' as it graces your garden with its captivating presence.
As we conclude our journey through the realm of cold-hardy agave that thrive in North Carolina's Zone 7b, it becomes evident that these remarkable succulents offer a delightful alternative to the conventional choices in temperate gardening. With their bold shapes, striking textures, and muted hues, cold-hardy agaves not only withstand the region's chilly winters but also bestow an enchanting allure upon any landscape they grace.
For those intrigued by agave species that may not be naturally cold-hardy in this zone, container gardening proves to be an excellent solution. By providing them with a suitable microclimate and protecting them during harsh weather, you can enjoy these exceptional agaves and their architectural splendor, even in colder climates.
So, whether you're a seasoned horticulturist looking for a fresh challenge or an amateur gardener seeking to add a touch of exotic elegance to your outdoor space, embrace the agave. Discover the world of cold-hardy agave that thrives in Zone 7b and experiment with container gardening to unlock the vast potential of this resilient and captivating plant family. The possibilities are endless, and the rewards are undoubtedly breathtaking. Happy gardening!