Primetime Newspapers
By Calvin Finch, PhD, SAWS Conservation Director, and Horticulturist
Week of November 15, 2004

Living Christmas Trees

            It is early to start thinking about your holiday tree but not if you want a living Christmas tree.  The idea of a living tree is to have something to use inside to decorate and then to have a tree to use as a permanent landscape plant.  Up until this year that has been very difficult because the species of trees offered as living trees were not those that survived very well.  This year at least one garden nursery and perhaps more are offering 3 varieties of conifer that look good as Christmas trees but also will make good landscape trees.  The varieties to look for are Italian Stone Pine, Aleppo Pine and Deodar Cedar.

            Afghan Pine (also called Mondale or Eldarica) has been the usual species of conifer offered as a living holiday tree.  A few of those planted still survive in the San Antonio area, but most are killed by a fungal dieback within 5-15 years after planting.  It is best not to select one unless you have rocky well-drained soil and there are not other Afghans in the vicinity.

            Deodar cedar, Cedrus deodara, is the tree that most resembles a blue spruce in our landscape.  The beautiful blue spruce will not survive but the equally beautiful Deodar will.  It is a true cedar from the west and is not in the same Genus as our hill country cedars.  It is a medium fast grower that can reach 40 feet tall.  If the Deodar has a weakness, it is that it is injured by severe cold.  Many of the largest specimens have a dead top that was killed by the freeze of 1990.  The bottom branches continue to live and it is still attractive but they have lost their conical shape.

            Aleppo pines, Pinus halepensis are also on the market.  If you want to see what they look like, visit Lackland AFB or Kelly Field.  The large pines gracing the landscapes are Aleppos. 

            Italian Stone Pines (Pinus pinea) do not grow as fast or as tall as Aleppos but they are well adapted to our alkaline soils.  The sheared holiday tree has a compact conical shape but once it is planted in your landscape it will make a dense globe and eventually form an umbrella crown eventually.  They make beautiful specimen trees.  Italian Stone Pine grow to about 35 feet tall in our soils. 

            I have not seen anyone offering Japanese Black Pine as a sheared living Christmas tree but if it is on the market, the gnarly looking pine will survive as a distinctive specimen in our landscapes.

            There are some tricks to use to receive full use and value from a living Christmas tree.  The trees are heavy because the container includes the roots and the soil.  Plan your moves to insure that you do not injure your back.  Use a moving cart and minimize the number of moves.  If you buy the tree now when selection is at its best, place the tree outside in morning sun until about one week before Christmas when you can move it to its temporary location in the house.  It is best if the tree only stays in the house for two weeks.  Avoid a location near heat registers or where the tree will get blasted by afternoon sun. 

            Water when the soil dries to 2 inches in the container and water until the water trickles out the drainage holes.  Outside, this is not a problem but inside you will want the container to be sitting in a drainage pan.

            Right after the holidays, move the tree to its permanent location in the landscape.  All of the trees recommended require full sun.  The Aleppo and especially the Deodar cedar should be at least 20 feet from the house.  The smaller Italian Stone Pine should be at least 10 feet away. 

            Dig the planting hole as deep (but no deeper) than the root ball and 2-3 times as wide.  There is no real advantage to fill the planting hole with potting soil or to use additives at planting.  If we have a wet spring, potting soil or compost in the planting soil can allow water to enter faster than it can drain from the hole making a soggy mess that will rot the roots.  The trees are well adapted to our soils (difficult as they are) and need to get their roots into the native soil to survive.