Plant Family
Pinaceae
Picea
Photo by: JAMES H. SCHUTTE
Plant Common Name
Spruce
General Description
Distributed throughout the cool, temperate zones and mountainous regions of North America, Europe, Asia and Mexico, the genus Picea includes approximately 35 species. Commonly referred to as spruces, these coniferous evergreen trees are valued for their ornamental qualities and long-grained, white wood used for making musical instruments and fine paper. The genus name Picea is derived from the Latin word for pitch, picis, and refers to the aromatic resin extracted from the wood.
Spruce trees typically have an upright, conical or spire-like habit with a single main trunk supporting evenly arranged branches. Young trees are covered with thin, scaly bark that becomes thick and furrowed as the trees mature. Whorls of sharply pointed, evergreen, needle-like leaves surround the branches and twigs. These are borne singly, and are attached either directly or atop short, peg-like protrusions. The needles may be square or angled in cross section, and usually persist on the plant for many years.
Reproduction occurs through separate male and female cones borne on the same plant. The pollen-producing male cones are produced on year old growth. These cones may be yellow or purple and are oval to cylindrical in shape. Wind carries pollen to the seed-bearing, green to purple female cones that usually appear at the upper branches of the trees. The pendulous female cones are narrowly cylindrical and become pale to dark brown when mature. The scales of the cones may be woody, leathery or paper-like, with smooth or toothed ends. Winged seeds are held between the scales, which mature within one year and are shed as the cone scales drop.
Among the most widely planted of spruces is Norway spruce (Picea abies), a graceful European species with deep green needles and an elegant form. Serbian spruce (Picea omorika) is native to high elevations of Serbia and Bosnia. It bears flattened, shiny dark green needles and is among the most tolerant of summer heat. The landscape favorite, Colorado blue spruce (Picea pungens), is native to the Rocky Mountains and boasts silvery, blue-green needles and a tall, majestic outline.
Generally, Picea species prefer full sun and neutral to slightly acid soils with good drainage, however climate and cultural requirements vary according to species and cultivar. Most perform best in areas with milder summers. These handsome evergreens make fine landscape specimens, and may also be planted as large-scale screens and windbreaks.