Conifers are cone-bearing trees and shrubs with needle-like or scale-like leaves. The majority of conifers are evergreen (trees and shrubs that keep their needles throughout the year), however, there are a number of important exceptions, such as larches (Larix), the bald-cypress (Taxodium) and the dawn redwood (Metasequoia), which are deciduous (lose their needles each fall). The American Conifer Society classifies conifers by growth rate:
Conifers can be planted in early spring (March to May) and early fall (September to October). As with all plants, try to plant your conifers on an overcast day when the tree will lose less water through transpiration (the evaporation of water from plants).
Dig a hole that is 2 to 3 times the width of the root ball and the same depth as the height of the ball (a wide and shallow hole). There are two schools of thought in terms of planting trees and shrubs: one school states that you amend the soil with organic matter and the other says that the tree will have the best chance of survival if you leave the soil alone. The idea behind the second theory is that the plant will be forced to adjust into the native surroundings without supplemental help. As you are moving the plant from one environment (the soil in the container or root ball) into a new one, why not give it a boost by adding at least some compost or equivalent?
When planting a container plant, rest the container on its side and carefully slide the conifer out of the pot. If the plant is root bound, loosen the roots with your hand, a hand cultivator (hand fork) or a knife so they are not spiraling in a circle around the root ball.
Balled and burlapped conifers should be placed in the hole intact. Position the conifer firmly in hole and make any adjustments while the burlap is still on the root ball. Cut the burlap, string and wire away from the trunk with a sharp knife or pruning shears and wire-cutters and gently pull the material away from the root ball. Try to slide the burlap out from underneath the root ball, gently tilting the tree to the side if necessary. Always remove the burlap unless the root ball is falling apart. If it is falling apart, remove as much of the burlap as possible without disturbing the root ball. Untreated burlap will eventually decompose, but it hinders the initial root growth that is important for the successful establishment of the tree. Fill in the hole and water.
When you are planting a conifer, make sure that the trunk flare (the point where the roots and the trunk meet) is slightly higher than ground level. This will compensate for the tree settling once it has been planted. Build a rim around the newly planted tree that will act as a saucer and allow water to collect around the roots.
Newly planted conifers will need regular watering for 3 to 6 months until the roots get established. For the first few weeks, check every 2 to 3 days to make sure the soil is not dry (stick your finger 2 to 3 inches into the soil) and water deeply if needed. In general, with trees and shrubs you can measure the diameter of the trunk and this will give you an idea of how many years you will need to go out and give it supplemental watering during dry periods in the summer and fall. For example, if the diameter is 2 inches, then keep an eye on the watering for 2 years.
Conifers are not heavy feeders; perform a soil test and fertilize according to the needs indicated. Many soils do not require any fertilizer. Garden centers often sell bio-stimulants for conifers that enhance root growth and are beneficial to newly planted conifers.
Conifers prefer cool soil temperatures. Mulching is an important step in the planting process and the maintenance of conifers. Mulch should be 1 to 3 inches deep and should not touch the base of the conifer (when mulch comes in contact with the trunk of the conifer it encourages decay). Composted bark and shredded leaf mulch are two good mulch options.
As a general rule, you do not need to stake conifers. They only need staking if you plant them in a windy location. Stake large conifers for one year until the roots get established. Weeping and pendulous conifers also need staking until they can support themselves.
While many conifers will not require any pruning, dead, damaged or diseased branches should be removed as soon as they are noticed, regardless of the season. In general, removal of healthy branches should be done just before new growth begins in spring; prune in late winter or early spring. With the exception of yews and hemlocks, most conifers cannot rejuvenate from old wood (grow new shoots and leaves from older branches). Cut branches back to a side branch (lateral) and do not cut back more than ⅓ of the total length of the branch. This type of pruning will produce a fuller and more compact habit.
Pines produce branches that are grown in whorls (clusters or groups). The easiest way to prune is to cut back to lateral shoots (side shoots) in 1st or 2nd year growth. Pines are often pruned by a technique called candling. Candles are the new shoots that emerge at the tips of the branches each spring. These shoots contain the needles for the current year’s growth. Remove ½ to ⅔ of the candle by pinching or snapping it off with your fingers. Spruce and firs are pruned in a similar fashion.
Candling is a good technique for dwarf or specimen plants; it helps to thicken the growth and give you a nice full plant. Many dwarf or variegated cultivars will revert (change back) to their original form. You will notice branches that do not have the same characteristics as the rest of the plant. Cut the reverted branches back to their point of origin.
For container plants, avoid conifers that have thick mats of roots on the soil surface or roots circling around the main stem. When selecting balled and burlapped conifers look for moist root balls that do not have large, torn roots sticking out of the ball. As a general rule, it is better to purchase smaller plants unless: (1) you are planting in an area with heavy foot traffic or (2) you are planting a dwarf conifer and do not want to wait years until it gets to the desired size.
These are some of the best remedies for removing pine sap: WD-40 on your tools; Technu™, mayonnaise or anything with vegetable oil in it on your hands; and rubbing alcohol or witch hazel on your hands and clothing.
Encyclopedia of Conifers by 
A Natural History of Conifers by 
Designing with Conifers by 
Pruning of Trees, Shrubs and Conifers by 
