By Marilyn Loser
It’s definitely spring in the San Luis Valley – too much real estate blowing around interspersed with some moisture and clear, crisp, still days. Too early to do too much in the flower garden, but definitely time to think about trees. I’ve been writing this column for five years now and I find that questions regarding new trees still come down to selecting a proper tree and digging the planting hole correctly.
If you’re interested in a hands-on experience, please join the Tree Board and the Parks and Recreation Crew in planting trees during Alamosa Arbor Week, April 27 to May 3. We’ll be planting 17 Crabapple trees of four species just south of Sunset Park (the ball parks along Hwy 285). They are partly financed through a Colorado Tree Coalition/Xcel Energy Vegetation Management grant. Also, we’ll plant 10 deciduous trees in the Alamosa Cemetery (Elm, Bur Oak, Cottonwood, Hackberry, & Boxelder). We’re firming up planting times this week. Please check the Courier or AlamosaTrees.net early next week for more information.
For this article, I’ll stick to deciduous trees (those that shed their leaves annually). If you plan to live in the same place for many years, this is a new addition to your family. Choose carefully! Colorado State Forester Vince Urbina offers four tips.
For a shade tree, pick one with a dominant central leader ( a main stem that grows straight up). I also look for a straight trunk that doesn’t divide like a wishbone – as the tree ages the wishbone could break. Look for smaller branches growing out of the main trunk. I didn’t know this when I purchased a Lanceleaf Cottonwood 12 years ago. Since then we pruned one of the ‘wishbone’ branches and the tree is coming along nicely. I would have saved the hassle of pruning and had a more mature tree if I’d picked a better one at the start.
Look for well-spaced branches. This is especially true with fruit trees, including Crabapples, that don’t have a dominant central leader as do shade trees. Avoid trees with a lot of downward growing branches or branches that cross over one another which can lead to later rubbing damage.
Look for above-ground vigor. If you’re planting the tree before buds break, look for healthy, un-shriveled buds and flexible branches. As sap rises in a tree breaking dormancy, the young branches become supple, and lose winter rigidity. Stand back from the tree and look at its overall structure. Is it reasonably symmetric? Also look for pruned branches. Seeing marks where lower, temporary branches were removed is typical. However, look for upper branches that were trimmed due to wounding or dieback. This may indicate a weak tree.
Look for root vigor. Most home owners that are planning to plant trees themselves buy trees in containers. So how can you tell how the roots are doing? I’ve learned to ask the nursery people to slide the tree out of the container so I can check. Before I knew this, many years ago, I purchased a small ash tree, planted it and it died a couple of years later. Pulling the carcass from the ground I noticed the roots had circled around girdling the tree rather than reaching outwards. The tree had probably been root bound at time of purchase. If only a couple of roots are starting to circle, you can gently pull them outward before planting.
“Planting practices have improved over time. Techniques used in the 1980s are considered inadequate today,” write Gary Watson and E.B Himlick in “The Practical Science of Planting Trees.” Current practices are research based.
About the planting hole. “It’s easy to dig too deep [and] wider is better”, say Watson and Himlick. For trees grown in containers, the planting hole should be no deeper than the root ball. The root ball must be supported by firm soil underneath to prevent settling. They also say, “Most new roots will grow horizontally from the sides of the root ball, so compacted soil at the bottom will not substantially affect overall root growth.”
While compacted soil is OK under the root ball, it’s not good in the around surrounding the tree. Most of the important fine absorbing roots will develop in the upper 12 inches of the soil. Trees should be planted so that the top of the root ball is 1-2 inches above the surrounding grade.
The hole should be three times the diameter of the root ball and dug in a cup shape. For more information and diagrams on planting trees, visit the Planting & Care section of AlamosaTrees.net.
“Always start with the best plant available. It is the cheapest part of the whole formula.” Vince Urbina, Colorado State Forester