Fall Color in Evergreen Trees? You Bet!

Now is the time when independent garden centers and nurseries all around the Midwest are fielding phone calls from new tree owners asking "Why are my trees turning brown??" Almost every time, once we see the photos, we can reassure them: it's just their fall color. And once you know what to look for, it can be quite a show.

Like the deciduous trees - maples, oaks, cherries and the like - all the evergreens we see around us also go through a fall color change and leaf drop each autumn. The leaves that fall aren't big and splashy, and of course they don't drop from the entire tree either. What happens instead, is that each tree species removes from its branches a certain age of needles every year. For most Pine species, the needles that are falling are either two or three years old. You can see that in the Red Pine shown below:

 

Spruces tend to hang on to their needles for 3 or 4 years, depending on what kind of spruce you're talking about. The White Spruce below is shedding what look to be four-year-old needles. And some Fir trees shed four-year-old needles, while other Fir species, like the Concolor, may hang on to their needles for as many as seven years. Other evergreens like Yews, Junipers and Arborvitae also experience fall needle drop. 

Fortunately for us, the color display can help remind us to pay attention to our trees in the fall. There are three things to manage in the fall: mulch, nutrition and water. Newly-planted trees (those in the ground for 3 years or less) should have mulch covering the root ball and roots for the winter, so they have the benefit of the soil's warmth for as long as possible. If it's there already, just check that it's 3-4" deep and not covering the trunk. If a little more is needed, October is better than November for an application - retain as much of that heat as possible.

Watering new trees doesn't necessarily end just because the air has cooled. Dormant trees are still using water, just not as much as they were in the summer. Performing a soil moisture check willhelp deicde whether to irrigate - they may want water right up through November 1.

Lastly, while you're putting on some water, a fall dose of root stimulator fertilizer is great for those new trees. A product with indole-3-burytic acid in a liquid or granular form can be applied to the surface fairly easily.

The fall color show provided by our evergreens can be a lot like the one we get from our deciduous trees. The range of color shades, as well as the timing and texture of the needles that drop all combine to add a bit more drama to the season. While it never hurts to ask us about it, I think it's one more reason to enjoy Autumn!