The black spruce (Picea mariana) is not native to Iowa. It occurs in the northeastern United States, and Minnesota, Wisconsin, and Michigan; from the northern range of North America to Alaska, Yukon, and British Columbia eastward to Nova Scotia, Newfoundland, New Brunswick, and Quebec and extending north all the way to the very limit of tree growth.
Hardiness: Zones 1 though 6
Growth Rate: Slow
Mature Shape: Narrow pointed crown; straight trunk with little tapper; short, compact, and drooping branches
Height: 40-50 feet
Width: 15-30 feet
Site Requirements: Thrive in partial to full sun with neutral or acidic soil; can tolerate poorly drained soil.
Flowering Dates: May - June
Seed Dispersal Dates: Retains cones in a semi-serotinous state
Seed Bearing Age: 10 years, but generally not in large quantities until 30 years
Seed Bearing Frequency: Yearly, with bumper crops every four years
Seed Stratification: Warm stratification for 16 days at 68°F to 85°F
Grows in muskegs, bogs, barren and stony slopes, but makes its best living in well-drained bottomlands. It is also often referred to as “swamp spruce” or “bog spruce.”
The leaves are needle-like, bluish-green in color, blunt-pointed, ¼ to 3/8 inch in length, and with a whitish bloom when young. The cones are short and ovoid, and measure from ¾ to 1 inch in length. The bark is grayish-brown with thin scales. It is believed that red and black spruces hybridize, and some authorities consider the red and black spruces to be variations of a single species – there is also speculation that black spruce hybridizes with white spruce, but not verified.
It is primarily used for paper pulp and Christmas trees, and secondarily for spruce beer and spruce gum in the northern regions.