You don't have to buy established blue spruce trees for planting; it's much more interesting to grow them from seed and then plant blue spruce seedlings (Picea pungens, USDA plant hardiness zones 2-7) into the ground. Also known as Colorado spruce, these trees are easy to grow and have pretty blue-green to silver-bluish needles, light brown cones and dark gray bark. The ones with the bluer foliage are more well liked than those with green, and when cultivated, they can grow as high as 60 feet tall.
Planting Colorado Blue Spruce Seeds
If you plan on growing spruce trees from seed, you'll want to start them indoors in seedling trays, plug trays or plant pots. First, soak your seeds in water for 24 hours, drain thoroughly and put them on damp paper towels. You can place them in a freezer bag and put that inside your refrigerator. Keep checking every few weeks and if they appear too dry, add some damp perlite or vermiculite. After four weeks, prepare your seedling trays.
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Fill the containers with high-quality general potting compost and sow the seeds directly onto the surfaces. Cover them with a fine layer of drained compost or vermiculite and water gently. They do best with about 16 hours of direct light per day, so put the containers in a sunny location. During the day, the room temperature should range from 55 to 85 degrees Fahrenheit; at night, 45 to 77 degrees is acceptable. You'll want to keep the soil moist, misting the seeds with water one or two times a day if needed.
Colorado Blue Spruce Sprouts
It can take up to a year or more for blue spruce seedlings to be strong enough for you to plant outside. Colorado blue spruce germination only takes 10 to 14 days, but the seedlings take their own sweet time to gather their strength. They can grow up to about 4 inches during the first year, and growth will accelerate after that. You can transfer the sprouts to larger containers once they outgrow their original homes.
Once you feel that your seedlings are healthy enough to tolerate the outdoors, you can get ready to transplant them. You should choose a spot with at least six hours of sun a day and well-draining, slightly acidic soil. Be sure to allow enough room since they can also spread to as much as 10 feet wide. Dig a hole two to three times the diameter of the tree's container but at the same depth. Keep the soil in a wheelbarrow or bucket and then gather together some mulch, plant food and a pair of pruning shears.
Planting a Colorado Blue Spruce
Add mulch to the soil removed from the hole you dug; a 1:2 ratio is best. Mix in a 7-4-4 plant food to that and then score the sides and bottom of the tree's root ball with your pruning shears. The next step is to lower the root ball into the hole and fill in the mulch/soil/plant food mixture. Stake and secure the spruce right outside the roots, ensuring that these are deeper than your soil mix. You can now dig out a well around the tree and add a "root and grow" mixture. Water the tree with this every two weeks during the first two months.
To give your baby blue spruce the best chances for success, water it once a month, checking the soil in between for dryness. They don't need a ton of water, so you may be able to get away with watering it once every two months instead. Fertilize it four times a year with a 7-4-4 product, humic or soil sulfur.