Fall Tree Care: More than Leaf Raking

By Marilyn Loser

The geese call as they fly over my home, the air is turning crisp, mountains both east and west have a dusting of snow, and the leaves are beginning to turn fall colors as I write this. My thoughts turn to fall tree care.  Leaf raking is a big task in many yards.  Add clearing sidewalks of both leaves and crabapples (please sweep or scrape them up to avoid winter “Slip and Slides”!)  to the task list and some people are on yard-task overload.  However, some fall maintenance goes a long way in preparing trees for their winter hibernation and spring renewal.

There are five issues to consider: mulching, pruning, watering, staking, and fertilizing.

Mulching: Young trees especially are susceptible to extreme temperature changes that may come with winter. They are usually not developed enough to withstand the constant freezing and thawing that occurs.  Did you know that Alamosa is ranked number two in the country for diurnal temperature variation (change in temperature between the warmest and coolest parts of the day) and ninth for annual temperature variation (change in temperature between summer and winter)?  Bishop, CA, is ranked first for diurnal variation and Fairbanks, AK, is ranked first for annual variation.

A layer of mulch 3-4 inches thick around the base of the tree, but not touching the trunk, helps stabilize the soil temperature and keep the soil moist. I check mulch in the fall and spring as our strong winds often rearrange the landscape in my yard and I need to level or add to the mulch layer.

Watering: Expert opinions vary on this issue. If you received as much rain as we did this weekend (one inch), it may be a moot point for September. Some suggest that you should stop watering deciduous and evergreen trees in early autumn and restart after the deciduous leaves have fallen – others content you should remain on a consistent watering cycle all summer and fall. The thinking of the ‘turn off water group’ is that trees are still growing in early autumn and watering will encourage new growth – which you don’t want. If a frost comes when there is new growth on the tree, the tree will be damaged.

By late autumn, water trees so that the top 1 – 1.5 feet of soil are saturated at the drip line for deciduous trees and even further out for evergreens.  If soil becomes dry, continue occasional deep watering until the ground is frozen. This doesn’t mean to keep the ground saturated all the time! The tops of deciduous trees go dormant in late autumn and will not produce new growth; evergreens don’t go into full dormancy and need water throughout the winter.

Pruning: I met a pragmatic gentleman at the yard waste recycling bin a couple of weeks ago.  His truck was full of trimmed branches in full leaf.  With a glint in his eye he explained that by trimming now he wouldn’t have to rake up all of the leaves from the trimmed branches. Sounds tempting but some experts suggest that waiting until leaves fall is healthier for the tree as the tree will have moved its stored energy from the leaves to the branches, trunk, and roots.  Trimming early deprives the tree of this important energy. You choose energy needs– yours or the tree’s!

Staking: Staking has largely gone out of fashion.  Most experts agree that a tree should only be staked if it needs protection from the wind. That may sound like most of Alamosa, but many trees, especially in downtown aren’t subject to high winds. As I walked around town this past weekend, I noticed a number of recently planted trees that had 2-3 ft-long stakes tightly strapped to the tree trunk.  The trunk was already split in one case as the tree tried to grow around the stake.  If you must stake, make sure to stake the tree loosely – it should sway in order to develop strong roots.  Material used to stake a tree shouldn’t cut into the bark. Remove staking after one year. Unstaked trees develop trunk girth faster and develop roots that allow them to stand up straight.

Fertilizing: I used to think that fertilizing trees in the fall would give trees energy to make it through the winter.  Now, there are different takes on this idea.  Some experts feel fall fertilizing promotes new growth at a time of the year when trees needs to be storing energy and  they suggest spring is a better time to fertilize. 

Whatever you choose to do for fall tree care, remember to smell the roses … oh, I meant, remember to look up and enjoy our beautiful fall trees.

“Trees are sanctuaries. Whoever knows how to listen to them, can learn the truth.” Herman Hesse