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- Giving Thanks for Gardening
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- Trial Plants winners for 2016
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The Homeowners Column
Evergreens – inside and outside
Extension Educator, Horticulture
Snow elevates every tree to a theatre stage. Every twig, branch, stem stands out with its backdrop of white velvet. Stop a moment to enjoy the free show of colors and curves of the naked trees. Evergreens offer a gift of gratifying green when all others are shades of brown and grey. Evergreens are prominent in our landscapes and in corner sales lots. However not all evergreens are created equal.
Evergreens 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 usually keep their needles 3 to 4 years whereas spruces retain them for several years so they appear 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". Not all plants with needles are evergreen. Nature loves a rebel. Trees such as bald cypress, dawn redwood and larch have needles, but shed their leaves each fall.
Learning tree identification is like learning to appreciate wine. Tree identification as in wine appreciation is learning to look for subtle differences, but without the ingestion of lots of crackers.
So as you are decorating your Christmas tree or hiking this winter, look closely and you may 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 needle bases of Fir (genus Abies) are expanded like suction cups. Needles look like little plungers. Their bare branches with round depressed leaf scars remind me of octopus legs. 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. In case you were wondering and to really confuse you further, Douglasfir is not a true fir, but is in its own genus. I won a free lunch once by knowing Douglasfir (or Douglas-fir) 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 also good choices as landscape trees.
Pines (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. Scotch pines have two short needles per bundle and are common as quality Christmas trees. Their stiff, dark green needles have good retention so are not as messy as some trees. Scotch pine can hold lots of heavy ornaments. They also keep their evergreen aroma throughout the season. However Scotch pines are lousy landscape plants due to their susceptibility to the deadly pinewood nematode.
As Christmas trees white pines retain their needles throughout the holiday season; however, their flexible branches will not easily hold heavy ornaments. White pines cause less allergic reactions as compared to more fragrant trees. They have long soft needles in bundles of 5. White pines make pleasant landscape plants and are a good choice for living Christmas trees for planting later in the landscape.