Soil and Sun
Pine trees benefit from well-drained soil that’s rich in nutrients. When transplanted, they need lots of soil around their roots, though large pine tree varieties sometimes make transplanting a challenge because of their deep tap roots. As sun-worshippers, most pine trees need full sun, including Pinyon pines (Pinus edulis) and Monterey pines (Pinus radiata).
Water and Mulch
Some pine trees are drought-tolerant, and those in damp climates don’t need watering other than rainfall. The only times you need to water pines are during dry winters, when they need a thorough soaking once a month to mimic natural rainfall. To prevent water stress, apply a layer of mulch around the base of the pine trees. This helps the soil retain water and prevents weeds from sprouting and stealing the pine tree’s nutrients.
Slow-release fertilizer helps young pine trees grow and mature pines remain healthy. Though mature trees can handle quick-release fertilizer, it may burn the sensitive roots of young pine trees. Starting with the second year of growth, pine trees need 2 to 4 pounds of a balanced fertilizer — such as one with a 10-10-10 ratio of nitrogen, phosphorus and potassium — per 100 square feet of bedding. If pine trees are large and in the open, you should measure the diameter of the trees’ trunks and apply 2 pounds of fertilizer per 1 inch of diameter for each tree.
Pine trees generally don’t need pruning. You can control size and shape your pine trees with light trims in late winter, but as evergreens, they won’t sprout new growth from the inactive centers, behind the green needles. This means that heavy pruning can leave pine trees bare and scraggly for years. Instead of chopping off tree limbs with gusto, increase bushiness by pinching off candles in spring. The only exception is when you need to remove a dead or diseased limb back to the branch collar, which is the swollen area at the trunk. When cutting off a diseased branch, it’s safest to wait until dry weather, as infected spores can easily contaminate pruning tools in wet weather, passing the disease onto other parts of the tree or garden.