Juniper, a widespread evergreen in the cypress family (Cupressaceae), is found across the Northern Hemisphere. Recognized for its distinct forms and foliage, this guide helps identify the plant by focusing on its appearance, leaf types, and unique cones, allowing for confident distinction in various settings.
General Appearance and Form
Juniper plants exhibit a wide range of growth habits, from low-spreading groundcovers to towering trees. Some species form dense mats, spreading several feet wide and reaching heights of 6 inches to 1.5 feet. These groundcovers, such as creeping juniper, are often used for erosion control or as ornamentals.
Other junipers grow as upright shrubs or small trees, reaching heights of 10 to 40 feet, with some varieties potentially growing up to 130 feet tall. These forms can be pyramidal, conical, or columnar, often with dense foliage. The overall silhouette and structure can vary significantly depending on the specific species and environmental conditions.
Needles and Leaves
Juniper foliage is a key identifier, presenting in two primary forms: awl-shaped (needle-like) and scale-like leaves. Awl-shaped leaves are sharp, pointed, and often stiff, appearing in whorls of three around the stem. These needle-like leaves are common on young juniper plants and some mature species, such as Common Juniper (Juniperus communis), where they persist throughout the plant’s life. Their color can range from green to bluish-green, sometimes with a white band on the upper surface.
Scale-like leaves are flattened, overlapping, and pressed closely against the stem, creating a compact and softer appearance. These are found on mature juniper plants. Many juniper species can display both awl-shaped and scale-like foliage on the same plant, with juvenile growth featuring needles and mature growth exhibiting scales. The texture of these leaves can vary from soft to prickly.
Cones (Often Called Berries)
What are commonly called “juniper berries” are modified seed cones, not true berries. These fleshy cones have fused scales, creating a berry-like appearance. They are typically small, 4 to 12 millimeters in diameter, and usually round or ovoid.
Juniper cones change color as they mature. Initially green, they ripen over 6 to 18 months, turning dark blue or purplish-black. Many mature cones feature a waxy, powdery coating, called “bloom,” which gives them a frosted appearance. These cones are found on female juniper plants, as juniper species often have separate male and female plants. Male plants produce small, yellow or tan pollen cones that are less conspicuous.
Telling Juniper Apart from Other Plants
Distinguishing juniper from other conifers involves observing its foliage, growth habit, and cones. Arborvitae (Thuja) plants have flattened, fan-like sprays of scale-like foliage, differing from juniper’s awl-shaped or tightly appressed scales. Arborvitae cones are small, leathery, and do not resemble berries.
Cypress (Cupressus and Chamaecyparis) species can appear similar to juniper, especially in their scale-like foliage. However, cypress trees often have a distinct conical shape and their cones are typically small, woody, ball-like structures with scales. Pine trees have longer, slender needles that grow in bundles of two or more, unlike juniper’s shorter, solitary needles or scales. Spruce trees have stiff, sharp, four-sided needles individually attached to the stem.