Colorado blue spruce, or Picea pungens, is a conifer that originates from the southern Rocky Mountains. It is most common in Colorado, but its range also extends into Utah and Wyoming. The Colorado blue spruce is a source of commercial lumber, and private growers use it as an ornamental tree. Seeds are the most common method of propagating the Colorado blue spruce. Like most conifers, its seeds require a period of cold weather to germinate. This tree is hardy in U.S. Department of Agriculture hardiness zones 8 and colder, and prefers winter temperatures of 10 degrees Fahrenheit or colder.
Things You'll Need
- Plastic bag
- Paper towels
- Planting pot
- Gallon container
- Potting soil
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Obtain the seed cones from a Colorado blue spruce. Pick off the ripe cones from a mature tree if possible or collect fresh cones from the ground.
Store the cones in a warm place to dry out. The cones should open within a few days. Extract the seeds from the cones by hand and remove the wings from the seeds.
Place some moist paper towels in a plastic bag and put the Colorado blue spruce seeds in the bag. Seal the plastic bag and put it in a refrigerator for at least a month.
Fill a planting pot with at least 6 inches of vermiculite. Sow the Colorado blue spruce seeds in the pot in early spring and cover them with a 1/4-inch layer of vermiculite. Place a 2-inch layer of mulch on top of the vermiculite and place the pot in partial shade. Keep the soil moist but not wet.
Select an outside site for the Colorado blue spruce seedlings in late fall to early winter. This is a temporary location that is safe from predators where the seedlings will spend the next two years.
Remove the Colorado blue spruce seedlings from the pots. Plant the seedlings in 1-gallon containers with general-purpose potting soil. Allow the seedlings to grow in these containers for two years. Apply a general fertilizer in the early spring and late summer.
Select a permanent location, with full sun, for the Colorado blue spruce trees. Transplant the trees to the permanent site in the late fall and space the trees at least 8 feet apart. Keep the area around the trees clear of weeds.