Extension Educator, Horticulture
Evergreens are now prominent in our landscapes and in corner sales lots. However not all evergreens are created equal. Knowing if it's a pine, spruce or fir can seem confusing?
Evergreens plants shed their leaves, usually as needles, throughout the year in contrast to deciduous plants that shed their leaves at the end of the growing season. The length of time an evergreen retains its leaves varies with the species. Pines tend to keep their needles 3 to 4 years whereas spruces tend to retain them for several years. Therefore spruces tend to look denser than pines. Not all evergreens have needles. Broadleaf evergreens include holly, boxwood and rhododendron.
Nature quickly teaches you to never say "never" and never say "always." Because not all plants with needles are evergreen. There are always a few rebels in nature. Trees such as bald cypress, dawn redwood and larch have needles, but shed their leaves each fall. The urban legends abound with stories of bald cypress getting the axe in winter at the hands of uninformed homeowners.
Since I sense your eyes starting to glaze over with "hat does this have to do with me?" I'll leave the definitions of conifers and gymnosperms to another time.
Learning tree identification is like learning to appreciate different wines. For me at first there were only two categories - what I liked and what I didn't like. I couldn't really verbalize why. I just new it was one or the other. Tree identification as in wine appreciation is learning to look for subtle differences, without the ingestion of lots of crackers.
So as you are decorating your Christmas tree or hiking this winter, look closely and you might be able to identify the evergreen before you. One important clue to evergreen tree identification is the way the needles are attached to the branches.
The needles bases of Fir (genus Abies) are expanded like suction cups. Needles look like little plungers. The bare branches are covered with round depressed leaf scars. They remind me of octopus arms covered with suction cups. Fir needles are generally flat with blunt ends.
Balsam firs are popular as Christmas trees because of their wonderful fragrance. Fraser firs are not as fragrant, but have good needle retention in the home. As landscape plants, firs suffer miserably during our summers. Concolor fir is the best fir for a Midwestern landscape plant. In case you were wondering and to really confuse you further, douglasfir is not a true fir, but is in its own genus. I also won a free lunch once by knowing douglasfir is one word. Just one more way horticulture adds to the world's economy.
Spruce (genus Picea) needles are held singly on woody pegs. The bare branches are very rough. Spruce needles are stiff and often very prickly. Planting a blue spruce is like hugging a porcupine. Spruces except for Norway spruce have good needle retention as Christmas trees. Spruces are good choices for landscape trees.
Pine (genus Pinus) have needles that can be quite long from 1 to 10 inches. The needles are borne in bundles also known as fascicles. One of the first tasks in identifying pines is counting how many needles are in each bundle. Scots pines have two needles per bundle. They are common as Christmas trees but make lousy landscape plants due to their susceptibility to pinewood nematode.
As Christmas trees white pines retain their needles throughout the holiday season. They also cause less allergic reactions as compared to more fragrant trees. White pines have long soft needles in bundles of five. White pines make nice landscape plants and are a good choice for living Christmas trees for planting later in the landscape. For more information on evergreens check out our website at www.urbanext.uiuc.edu