Plant Profile: Holly

It’s a plant best known for decking the halls, but holly goes far beyond holiday decorations. This diverse group of plants has been around for millions of years, and can be found on every continent except Antarctica. From its use in drinks, to the Garden’s impressive living and research collections, discover the story behind this incredible plant.

What is Holly?

Hollies belong to the genus Ilex, a large genus of trees and shrubs in the plant family Aquifoliaceae. Most of the more than 400 species are evergreen, although some, like the Missouri-native possumhaw (Ilex decidua) and winterberry (Ilex verticillata) are deciduous, meaning they drop their foliage in the fall.

The holly most associated with the holiday season is Ilex aquifolium, otherwise known as English holly. It’s American cousin, Ilex opaca, has a very similar appearance.

Most hollies have simple, alternate leaves, often with spiny margins. The plants are dioecious, meaning there are separate male and female plants. Although both produce small, white flowers, only males produce pollen, and only pollinated females produce the colorful “berries”(which are technically drupes) that holly is known for. Holly drupes can be toxic to humans and pets, but they are a great food source for birds.

Term to Know – Drupe
A drupe is a fleshy fruit with a thin skin and one or more hard stones or pits, each of which contains one or more seeds. Peaches, cherries, walnuts, and almonds are all examples of drupes with one stone. Hollies have four to six.

Living Collection

Winter is one of the best times to view the Garden’s Ilex collection, when the bright “berries” add a pop of color to the winter landscape. The living collection includes more than 700 individual hollies, representing a wide variety of hardy species and cultivars.

There are more than 150 American hollies throughout the Garden, but the species is actually quite rare in Missouri. Wild populations of Ilex opaca are found in only a few counties near the bootheel, with the rest of the species distribution found in southern states. The Holly Ridge Conservation Area is a great place to see wild American holly in Missouri.

There are two areas in the Garden where this species shines. The Holly Fields, just east of the Lehmann Rose Garden, feature about 30 of these trees. And along the historic stone wall in the Victorian District, you’ll find a row of Ilex opaca cultivars such as ‘Chief Paduke’, ‘Warrior’, and ‘Canary’. Notice the differences in the color and abundance of drupes on each cultivar, or differences in the foliage.

American holly, *Ilex opaca* ‘Canary’ Photo by Tom Incrocci.

The living collection features deciduous Missouri natives Ilex verticillata and Ilex decidua. The bright red fruits you see in the Garden’s main parking lot during a visit to Garden Glow belong to the winterberry. And of particular note is a former state champion possumhaw that sits just west of the Stephen and Peter Sachs Museum.

The Garden’s collection also includes Foster holly (Ilex x attenuata ‘Fosteri’), featured prominently as a hedge-row in the Kemper Center for Home Gardening. Some other highlights include inkberry (Ilex glabra), the myrtle-leaved holly (Ilex myrtifolia), and Chinese holly (Ilex cornuta). Yaupon holly (Ilex vomitoria), a common species in the southeastern U.S., can be found in the Temperate House.

Biocultural Collection

Due largely to its association with the holiday season, English holly holds the most obvious link between people and this genus of plants. Its cultural symbolism can be traced back to the druids. It also appears in more contemporary use beyond winter decoration. For instance, famous boy wizard Harry Potter uses a wand made of holly wood.

The Garden’s biocultural collection highlights different kinds of relationships between people and these plants. Several species are used not as decor, but as a drink. Yerba mate, a beverage popular in South America, is made from Ilex paraguariensis. The same is true of Ilex guayusa. Both plants contain caffeine, and the leaves are dried and steeped as a tea. Our biocultural collection includes several commercially sold packages of yerba mate and guayusa.

There are records of other hollies being used in beverages because of their caffeine content. Yaupon tea, made from Ilex vomitoria, was used by Native Americans for hundreds of years. Traces of it have been found in pottery fragments at Cahokia Mounds State Historic Site in Illinois.

The species name vomitoria comes from its use in Native American rituals that included fasting and vomiting. Despite the name, the drink does not cause vomiting. Yaupon tea is making a modern-day comeback as more people rediscover its caffeinated property. We tried it ourselves, and it’s pretty tasty!

Herbarium

There are nearly 5,000 specimen data records for Ilex in the Garden’s online plant database, Tropicos. These records are tied directly to voucher specimens in the Garden’s Herbarium. The specimens were collected all over the world, and can be used by researchers to answer questions about species diversity that often lead to the discovery of new species.

St. Louis native and former Missouri Botanical Garden researcher Julian Steyermark described nearly 40 new species of holly in his career. Many of these species were collected in Venezuela, where Steyermark worked extensively. Among those species is Ilex davidsei, named for current Garden researcher Gerrit Davidse.

Vouchers collected by the Garden’s first director, William Trelease, can also be found in the Herbarium collection. Check out the mounted specimens included in this post. Can you spot the similarities and differences between these species?

*Ilex vomitoria* collected near the Brazos River in southern Texas in 1899.

Library Collection

The Garden’s Peter H. Raven Library has dozens of publications on its shelves dealing with holly. There are checklists and handbooks, guides to identification, and books about cultivation and home gardening. The collection also includes newsletters, bulletins, journals, and other publications from the Holly Society of America.

Exquisite images of Ilex species can be found in a number of works in the Garden’s rare book collection. Many of these illustrations have been digitized by the Garden or other institutions and made available online through the Biodiversity Heritage Library.