Flower gardeners frequently use the term “lily,” but not all plants referred to as lilies are considered true lilies. The North American Lily Society acknowledges nine horticultural groups of garden lilies that fit the Lilium genus and are recognized as true lilies. True lilies grow perennially from bulbs that have a distinct scale structure and produce large, showy flowers. While over 80 species exist in this genus, most garden-grown plants are hybrid crosses of native species or cultivars selectively bred from those hybrids. Although many plants have the word lily in their common name, they are not genuine lilies. Examples of such plants are daylilies, toad lilies, peace lilies, and water lilies. It’s important to note that several true lilies, including the Stargazer and Easter lilies, are poisonous to cats. Find out more about the nine types of authentic lilies recognized for your garden.
The ‘Lollypop’ cultivar of Asiatic lilies is a favorite among beginners due to its ease of growth, making it one of the most popular types of lilies. It belongs to Division 1 in the official horticultural classification system and comes in a wide range of colors, although it may not have a distinct scent. These lilies bloom in June or July and can face up, down, or outward. While they are not commonly grown in container gardens, the dwarf 12-inch-high ‘Buff Pixie’ can adapt to pot growing. Asiatic lilies are a result of genetic crosses between species native to central and eastern Asia, as well as interspecific hybrids. They are derived from nursery hybrids, and their parent species are native to eastern and central Asia. These lilies prefer full sun to partial shade and can grow up to five feet tall in USDA zones 3-8.
Martagon hybrids, also known as Turkscap Lilies, belong to Division 2 in the official horticultural classification system. These lilies are known for their downward-facing flowers that resemble a turk’s cap, and their stems can reach up to six feet tall. They bloom in late spring or early summer and prefer partial to full shade, making them suitable for woodland gardens. Martagon hybrids are derived from the species Lilium martagon, which is native to Europe and Asia. They are hardy in USDA zones 3-8 and make excellent cut flowers.
Martagon hybrid lilies belong to Division 2 in the classification system, and are named after one of their common genetic parents, L. martagon. Although these hybrids can be challenging to grow, the stunning 5-to-6-foot wands of mature plants make them worthwhile. Turkscap lilies is another name for these hybrids, as they resemble the shape of the blossoms. Plant them during autumn in a sheltered location with proper drainage, and expect fragrant blooms between May and June. These lilies are the most shade-tolerant garden lilies, making them suitable for the edge of a woodland garden, but away from competitive tree roots. Martagon lilies do not transplant well, so choose your location carefully. These nursery hybrids have parent species that are native to Asia and Europe, and thrive in USDA Hardiness Zones 3-9. They grow to a height of 3-6 feet and require full sun to partial shade.
Candidum lilies are historical plants that have been passed down through generations as open-pollinated varieties. These type of heirloom plants, known as Division 3 lilies, originated from lilies native to the Balkans and Middle East, some of which have become naturalized in Europe. They are commonly referred to as Madonna lilies due to their symbolization of purity in Christianity. However, finding these lilies for sale in the nursery trade can be a challenge. Candidum hybrids require a sheltered area with an eastern exposure that receives morning sun. Additionally, it is important to adjust the soil’s pH level to neutral and plant the bulbs just below the surface, about an inch deep. These lilies prefer slightly dry conditions and can be susceptible to grey mold if planted in damp locations. During the summer, white trumpet-shaped blooms will emerge. The American Hybrids or Lillium Hybrids in Division 4 are another type of lilies worth noting.
Division 4 of the hybrid lily classification system comprises a group of lilies created by crossbreeding different native North American species. One of the popular members of this division is the Humboldt lily that thrives well in humus-rich soil with proper drainage, forming large colonies in gardens. These lilies feature impressive floral candelabras with downward-facing and sharply recurving petals, making them an ideal fit for informal landscapes and wildflower gardens. Their naturalization is easy since they are derived from native North American species. However, distinguishing between true native species, naturalized hybrids, and non-native species can be challenging since they all appear similar. For instance, the tiger lily commonly found along roadsides is typically an Asian species such as Lilium lancifolium or Lilium tigrinum. Longiflorum hybrids, classified under Division 5, are also popular nursery hybrids with their parent species originating from North America. They thrive best in areas with partial shade to full sun but tend to do exceptionally well in dappled shade.
The Division 5 longiflorum lily group, commonly known as the Easter Lily, is a favorite among gardeners due to its seasonal blooming in the spring. In July or August, these lilies produce beautiful white trumpet-shaped blooms in the garden. Unlike many other gift plants, the Easter Lily can be successfully transplanted to a permanent location outdoors. To ensure optimal growth, choose a sheltered spot where the blooms receive plenty of sunlight while the roots remain shaded. It’s essential to keep the foliage intact and provide regular watering. These lilies are native to the southern islands of Japan and Taiwan and thrive in USDA Hardiness Zones 4-8. The height ranges between 2 to 3 feet, and they require full sun exposure. Additionally, Trumpet Lilies or Aurelian Lilies (Lillium Hybrids) fall under Division 6.
Division 6 is a group of trumpet lilies that are named after their bugle-shaped flowers. The group contains numerous Asiatic lilies with tubular, trumpet-shaped flowers or crosses of such Asiatics. Aurelian hybrid is a term used for a trumpet lily that has L. henryi, a Chinese native species, as one of its parents. Although trumpet lilies are less cold-resistant than other lilies, they are easy to cultivate if you stake them to safeguard their enormous blooms and provide them with a layer of insulating mulch during the winter. ‘Golden Sunburst’ is a cultivar that is more drought-tolerant than other lilies and can grow up to 8 feet tall if taken care of properly. Division 7, Oriental lilies (Lillium Hybrids), consists of many popular lilies that are recognized for their alluring fragrances.
Oriental lilies, categorized as Division 7, are quite similar to Asiatic lilies in terms of their physical characteristics and color selection. However, what sets them apart from other types of lilies is their sweet fragrance that is unmatched and hard to resist. These lilies can be a bit picky, but gardeners don’t mind the extra effort because of the lovely scent they offer. They thrive best in soil that is rich in humus and acidity. You can achieve the perfect soil condition by adding organic materials like compost and leaf mold. These beautiful flowers will start blooming in August when most other flowers are coming to an end. Oriental lilies are hybrids, with L. auratum (native to Japan) and L. speciosum (native to Japan and southern China) being the parents of many cultivars. These hybrids are typically grown in nurseries and are native to eastern Asia. They are hardy in USDA zones 4-9 and grow up to 3-5 feet in height. They require full sun to partial shade to thrive. Moving on to Division 8, Interdivisional Lilies or Lillium hybrids also make a great addition to any garden.
Division 8 encompasses a diverse group of hybrid lilies that are created by crossbreeding plants from other lily classifications. One example of this includes LA lilies, which are produced through the crossing of L. longiflorum and Asiatic varieties. This results in flat, sizeable flowers with a mild fragrance. Meanwhile, Orienpet lilies have a similar scent, stature, and hue to Oriental lilies but possess the robust growth pattern of trumpet lilies. These nursery hybrids can thrive in full to partial sunlight and are typically found in USDA Hardiness Zones 3-9, with varying heights depending on the species. On the other hand, Division 9 lilies refer to species lilies (Lillium spp.).
Division 9 of lilies comprises unhybridized pure wild types, including the well-known wild tiger lily. These species are highly adaptable as they originate from diverse habitats such as swampy jungles and frigid mountains. While the number of species lilies available in the market depends on the nursery, you can always find unique varieties like Lilium aratum ‘Gold Band’ by connecting with lily societies or visiting specialty nurseries. It is possible that there are still undiscovered lily species in remote regions that could contribute to future hybrids. These species are native to various regions, and their USDA Hardiness Zones and height requirements vary. Species lilies can grow in full sun or full shade depending on the type.