By Val Whitmyre, U. C. Master Gardener
You may be tempted to plant your living Christmas tree after the holidays, but before you dig that hole, make sure your tree will thrive in our valley. Look for the identification label, or consult with your local nursery. Most trees sold as Christmas trees thrive better in their native mountains, but a few do grow well here. v
The Colorado spruce, Picea pungens, is a slow grower, reaching about 10 feet in 10 years. But it can eventually reach 100 feet, so give it a lot of space. Don't plant it close to fences or buildings. This is the perfect pyramid-shaped tree for a front-yard Christmas tree. Your tree may be 'Fat Albert,' a variety sold mainly for Christmas. 'Fat Albert' is a blue-gray compact tree that needs little or no pruning. v
Another spruce, Picea glauca 'Conica,' grows to only seven feet in 35 years. It would make an excellent small-container Christmas tree for many years. Spruce trees aren't fussy about soil, but they don't do well in harsh, windy areas. Both of these spruce varieties will thrive in Napa Valley.
Firs are the most popular Christmas trees. The white fir, Abies concolor, grows best in the mountains in Sunset Zones 1 and 2. I confirmed this when I brought a small fir tree home from my Tahoe property in a gallon container, thinking I would eventually have a good-sized living tree.
Three years later, my little tree hasn't grown one inch. I suspect it didn't like being transplanted to a different environment. However, it is alive and makes a less than impressive bonsai tree. This majestic native of the high mountains does grow in the Napa Valley, albeit slowly. In Southern California, it is grown as a container plant.
The more visible and less expensive cut Christmas tree is the Douglas fir. Not a true fir, it is in the Pinaceae family and grows to 250 feet in high mountain forests. Its dense branches have soft, dark-green needles and cones that hang down, while the cones of true firs point upward. I know that it grows here because one of my family's Christmas traditions is a trip to a Napa Christmas tree farm to cut the perfect Douglas fir.
Two other fir trees definitely require the cold winters of Zones 1 through 7, where snow covers the ground most of the winter. If your Christmas tree is a red fir, Abies magnifica, usually called a "silver tip," the only suitable growing place would be a mountain property. Even then, having already endured the indoor heat of the holidays, it might not survive. The noble fir (A. procera) is similar to the magnifica in appearance and environment requirements and not a good choice for our area.
If you bought a small container pine, chances are it is a Picea pinea, or Italian stone pine, short and bushy with soft, blue-green needles. It is a good tree for California valleys and coastal areas, but it won't grow into a Christmas tree form. Eventually, it will have an umbrella canopy and reach 40 to 80 feet.
The Japanese black pine, Pinus thunbergii, is a handsome and versatile tree. After the holidays, you can cut and train it to almost any shape. The styles used in bonsai, such as windswept, informal upright or cascade, would also be striking in the garden. I use a Japanese black pine bonsai tree as a centerpiece in my house but take it outside where it belongs right after the holiday feast.
All of these trees except the "silver tip" and noble fir are worth trying if your garden has the space. None of them require special soil, but all need good drainage and a protected spot away from the wind.
If you don't want to plant your living tree, try calling the local schools. Planting a tree can be a good learning experience for children. Or call the city tree department and ask for suggestions. Perhaps city employees would plant your tree in one of our parks.
If the tree is already showing signs of dying, cut it for kindling, or mulch it and use it around another tree. Live Christmas trees are usually sold in containers, so you could keep your tree contained for a year or so, little by little cutting back a third of its roots, then replanting it and turning it into a bonsai specimen.