The jack pine (Pinus banksiana) is a native of the Lake states, the northern New England states and much of Canada. It has been planted widely in Iowa, but is a less desirable tree than many of the other pines. It will survive on the driest soils in the state, and makes rapid growth during the first 10 to 15 years. It is a rather small tree, reaching a height of 40 to 60 feet under favorable conditions. Normally the tree has thin, open foliage and is not tolerant of shade. As the lower branches are shaded and die, the old cones remain on the tree for many years.
Hardiness: Zones 3 through 7
Growth Rate: Rapid
Mature Shape: Crown becomes irregularly rounded or spreading and flattened
Height: 30-50 feet
Width: 10-18 feet
Site Requirements: Especially hardy on dry sandy soils but adaptable on most well drained soils
Flowering Dates: May - June
Seed Dispersal Dates: September
Seed Bearing Age: 3-15 years
Seed Bearing Frequency: Every 3-4 years
Seed Stratification: Prechilling for one week at 34°F to 40°F
The needles occur in bundles of two and are shorter than most other pines, 3/4 to 1-1/2 inch long, and are quite stiff and pointed and tend to spread apart from one another forming a V.
The small cones are about 1-1/2 inches long, often strongly curved, persistent and sometimes remain on the trees and contain good seeds for many years. The cone tips curve toward the branch tips. Cones are green or purplish when full-grown, turning light yellowish-brown as they ripen.
Jack pines tend to have straight trunks. Their branches are long and spreading, forming an open ragged crown. The dark brown bark is irregularly divided into small scales.