Eastern redcedar (Juniperus virginiana, L. 1753)

Identity

Eastern redcedar (Juniperus virginiana L., 1753) is a conifer in the Cupressaceae, native to eastern North America and hardy in USDA zones 2–9. Despite its name, it belongs to a different botanical group from true cedars, Cedrus. English settlers compared its reddish, fragrant wood with that of Mediterranean cedars, giving rise to the common name. ^{7 1}

The alternative name Pencil cedar recalls a former industrial use: until the middle of the twentieth century, its soft, easily sharpened heartwood supplied most pencils manufactured in the United States. ²

Recognition

An established Juniperus virginiana typically reaches 5–20 m (16–66 ft) tall, with a trunk 30–100 cm (12–39 in) across in old specimens. Its foliage is dimorphic: seedlings and shaded shoots carry sharp needles 5–10 mm long, while adult trees develop opposite, closely pressed scales 2–4 mm long, giving the crown its dense, bluish appearance. ^{6 7}

Reddish-brown bark peels into long fibrous strips, providing a useful identification feature outside the growing season. The species is dioecious: tiny male cones shed highly allergenic pollen in late winter, while the berry-like female cones measure 3–7 mm and turn blue-purple beneath a waxy bloom when ripe, after 6–8 months. ⁶

Useful taxonomy

The accepted name, Juniperus virginiana L., encompasses a broad horticultural and botanical synonymy. Useful names to recognize include:

• Juniperus virginiana var. virginiana, the typical variety, widespread inland
• Juniperus virginiana var. silicicola (Small) J.Silba, a coastal form of the southeastern Atlantic and Gulf coasts, sometimes treated as a separate species
• Juniperus virginiana var. bermudiana (L.) Vasey, another name in the synonymy
• Juniperus foetida var. virginiana (L.) Spach, a historical combination

The varieties virginiana and silicicola hybridize extensively where their ranges overlap. This helps explain why some regional floras treat Juniperus virginiana as a single species with a broad ecological range. ^{1 7}

Habitat and range

Across eastern North America, its native range runs from southeastern Canada to the Gulf of Mexico, east of the Great Plains, with an isolated extension into Coahuila, Mexico. Farther west, Juniperus scopulorum replaces it; to the southwest, Juniperus ashei takes its place. ^{1 7}

As a pioneer, Eastern redcedar is among the first trees to colonize neglected grassland, old pastures and bare limestone ledges. Birds play a major role: cedar waxwings eat large quantities of its berry-like cones, and seeds that pass through their digestive systems germinate about three times as successfully as those remaining on the tree. ^{7 6}

Frequent prairie fires normally hold this fire-sensitive tree in check. Low branches touching the ground act as a ladder, allowing flames to engulf the whole tree. A century of fire suppression has reversed that balance, and Juniperus virginiana now spreads across large parts of the Great Plains, changing grassland bird communities. ⁶

Life cycle and reproduction

Late-winter flowering takes place on separate male and female trees. Abundant pollen from the male cones is among the most potent respiratory allergens in North American vegetation at that time of year. ⁷

A pollinated female tree produces berry-like cones that ripen in 6–8 months, each containing one to four seeds. Winter stratification and passage through birds break seed dormancy, so natural germination is spread over several seasons rather than occurring all at once. ⁶

Horticulturists use semi-ripe shoot cuttings to reproduce cultivars faithfully. Slower propagation from seed produces variable offspring and supports genetic diversity, useful for conservation plantings and windbreaks. ^{4 5}

Uses and risks

Pink to reddish-brown heartwood is light and durable even in contact with soil. It supplied most wooden pencils until available stocks dwindled around the 1940s, after which incense cedar, Calocedrus decurrens, replaced it. The same heartwood remains sought after for lining chests and closets because its scent repels moths. ^{7 2}

Essential oil distilled from wood shavings contains alpha-cedrene, thujopsene and cedrol and is used in perfumery and insect repellents. The berry-like cones are eaten raw or cooked in small amounts, but their resinous taste is less popular than that of Juniperus communis, the standard species for flavoring gin. ⁴

Major toxicological databases classify Eastern redcedar as non-toxic to cats and dogs, although prolonged contact with sap or essential oil can irritate skin and mucous membranes. For fruit growers, another concern is its role as the obligate alternate host of cedar-apple rust, a fungal disease that needs this tree and an apple or pear tree to complete its life cycle. ^{5 6}

Varieties, look-alikes and related plants

Named cultivars vary in habit and foliage color: Canaertii is columnar and dark green; Grey Owl is spreading and silvery-gray; Hillii is narrowly upright and turns purple-bronze in winter; and Burkii has a blue-green pyramidal crown. All four retain the typical species’ tolerance of limestone and drought. ³

Plants most likely to cause confusion include:

• Juniperus scopulorum, which replaces J. virginiana west of the Great Plains;
• Juniperus ashei, found in Texas and responsible for seasonal “cedar fever” in the southwestern part of the range;
• Thuja occidentalis, whose flat foliage fans and woody, non-fleshy cones distinguish it clearly from a juniper on close inspection.

Cone shape is more reliable than foliage color when separating Eastern redcedar from Thuja occidentalis: the former has fleshy, berry-like cones, while the latter has dry, scaly cones. ⁷

Main sources

• Plants of the World Online / Kew, Juniperus virginiana L.
• Royal Horticultural Society, Juniperus virginiana (pencil cedar)
• Missouri Botanical Garden Plant Finder, Juniperus virginiana
• Plants For A Future, Juniperus virginiana
• NC State Extension Gardener Plant Toolbox, Juniperus virginiana
• USDA Forest Service, Fire Effects Information System, Juniperus virginiana
• Encyclopaedia Britannica, eastern red cedar
• IUCN Red List, Juniperus virginiana assessment