Mulching around old and new pine trees is beneficial since it reduces water stress and weed population. Pine bark or pine needles are good mulching materials.
To encourage roots to spread in search of food in the soil, do not feed newly planted trees for their first season.
Conifers such as pines bleed, or leak sap, when they are pruned. Minimize this by pruning only 1/3rd of their new growth each year. Prune them early in the season, just after the soft new growth shoots, or “candles”, develop at the branch tips and before they sprout long needles. Cut back the center candle quite close to its starting point to enable it to produce new buds on the remaining short sections. Repeat this annually if you wish to keep the tree about the same size and to make it denser.
For the first several months after planting, watering may be necessary during dry periods to prevent water stress on new roots and shoots. . Once they are established they don’t usually require supplemental watering, especially if they are well mulched. Their long taproot offsets the effect of dry soil and mild drought.
If you prune pine trees during a dry summer or, in southern areas, during the summer, you invite attack by bark beetles. Sometimes the beetles attack in such numbers that they kill a tree.
After the pine tree has been in place for a year feed young pines once a year in the fall for a few years. Sprinkle fertilizer or one formulated for acid loving plants on the soil under each tree out to 1 to 1 1/2 times the distance from the trunk to the tip of the branches. If the distance is 20 feet, fertilize 10 feet beyond the tips of its branches, (the drip line), for the rain to soak in. Do not allow the fertilizer to touch the tree trunk. Use 1 cup or so of fertilizer for every inch of trunk diameter. After 4 or 5 years well-mulched pines do not need regular fertilization. The continual decomposition of the mulch provides nutrients and organic matter that enriches the soil so it can support them.
Just before winter sets in water pine trees well so that they will have water available to them after the ground freezes. This is especially important to trees and shrubs that keep their leaves all winter. During periods of prolonged drought even well established pines need water.
Always prune out broken or diseased branches promptly to forestall disease and insect invasions. Cut them off cleanly back at the point where the branch joins another and the wood is healthy. If you cut way back to older, bare wood no new shoots will develop. Try to maintain lower branches longer than upper ones so that they receive sufficient light. Then trees will stay dense and bushy all the way to their base.