Pinaceae : Pinus ponderosa
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Family Name
Pinaceae
Common Name
Ponderosa pine
Description
Pinus ponderosa is a large evergreen tree with a pyramid-shaped crown that broadens with age and can reach 35 m in height. The trunk is straight, gray brown and furrowed when young, becoming scaley and gray mixed with orange brown with age, and the branches are gray black in color. The needle-like leaves are clustered toward the branch tips, usually 3 (2) per fascicle, 8-20 cm long, with small teeth along the margins. The fascicles emerge from a membranous, orange brown, deciduous sheath that is 1.5-2.5 cm long. Ponderosa pines are monoecious, the male cones are yellow orange, cylindrical, 1.5-3 cm long, in axillary clusters of 10-20 cones. The female cones are brown, woody, broadly ovoid, 6-12 cm long, 6-8 cm wide, and mature in the second year. Each cone scale has a thin prickle on the outer side. The seeds are in pairs underneath the scales, 6-7 mm long with a papery wing 3-4 times as long as the seed. The cones release pollen in May and June on low mountains and rocky hillsides in western and southcentral South Dakota.
Horticulture Notes
Seed collection: Cones are collected in October and November when they are reddish brown and the seeds are firm and brown. The cones must be air dried to prevent mold development.
Germination: Seeds from SD plants have little dormancy and will germinate with either fall or spring planting. Seeds can be stored for several years if kept cool and dry, but become dormant and need a 60-day cold moist treatment or fall sowing.
Light: Full sun.
Soils: Coarse, well drained soils are best.
Water: Seedlings need to be kept moderately moist until they are established. Trees grow well in moderate to dry conditions.
Additional Notes
Ponderosa pines are native to the western half of SD but have been planted in yards and wind breaks throughout the state. These pines are an impressive choice for larger spaces. They are fast-growing, long-lived trees that can add more than 12 inches per year.