A PLANTING PRIMER
Rich Atkinson

The Challenge

There do exist on this planet places where trees routinely forgive planting ignorance. Perhaps you’ve been fortunate to grow in one of these “stick it in the ground and forget it” places, a place that afforded you unabashed admiration of, heck, might as well admit it, both of your thumbs. Well, Santa Fe is not one of those places. So many difficulties face the Santa Fe gardener that even the most respected will, at least in private, confess to multiple failures. There’s the soil (or lack of it), the terrain (rarely flat), and alkalinity (borderline toxic), the drought (what part of “High Desert” can’t we fathom?), the altitude (maybe it should be “Desert High”), the heat (how many records did we just break?), the low humidity and desiccating wind. In fact, about the only aspect of gardening in Santa Fe that we can completely control is knowledge. Do it right and plants will join us in that kinship we both need; do it wrong and we’ll be party to the death of a dependent.

The Selection

It’s a pretty short list, the trees and shrubs that like it here. Diversity is great but don’t go too far off the climate/soil map. Local nurseries can’t have you complaining that the magnolia they sold you died so they stock what works. Most will special order borderline trees and shrubs but they’ll warn you of the risks. If you positively, absolutely have to have a beech tree, it’s probably best to move to New England.

A wise man once said, “A wise man plants a tree under whose shade he never expect to sit." That is, start small. Small trees establish faster than large transplants. Small trees cost less than large ones. In three to five years, a small tree will catch up to and pass a large one planted at the same time.

Location, Location, Location

Where you plant is just as important as what and how you plant. You must know what conditions will contribute to the success of your planting - —hours of sunlight, sheltered versus exposed habitat, tolerance of wind, compacted soil, etc. Consult your nursery, textbooks, and the Internet; learn as much as you can about your new tree. Above all, be certain that the location you’ve chosen can physically accommodate the tree you’ve selected. Small trees can get very, very big.

The Hole

Formulas tend to enable gardeners to take some of the guesswork out of planting. For instance, when planting a tree, dig a hole that is at least twice the diameter of the rootball/container and exactly as deep as the rootball/container. A container with a 12-inch top diameter will require a hole with at least a 24-inch diameter. A container with a height of 18 inches will require a hole 18 inches deep. If you really want to burn some extra calories, enlarge the hole’s diameter; digging deeper can actually harm a transplant.

INSTALLATION
You have the right hole dug in the right location for the right tree. Now comes the hard part.

If your new tree is in a container, gently remove it (it may be necessary to cut away the container) and place it in the center of the hole. If your new tree is wrapped in burlap, a wire basket or chicken wire, place it in the hole first and then remove any soil and all artificial restraints (burlap, wire, twine, etc.). It may not be possible to remove these materials from beneath the rootball but since almost all root growth is lateral, not down, the ball’s sides must be unwrapped. Your tree should now be sitting with the top of its rootball level with the surrounding native soil.

Backfilling

Perhaps the most debated part of tree planting is the use of soil amendments, things you add to native soil to improve a new tree’s chance for a long, productive life. Key to this discussion is the fact that your new tree, if it is to thrive for decades, must make its living in your native, unamended soil. You could excavate about 5,000 square feet of your yard to a depth of 24 inches, truck in about 20 cubic yards of soil amendments, mix and stir the amendments and your native soil with a backhoe and refill your yard with this mixture. Or, you could select a tree capable of thriving in your native soil, slightly amend the soil you dug from the hole and begin backfilling.

Over-amended planting soil can cause tree roots to remain in the “good stuff." You need to induce new root growth into your native earth. This is the greatest challenge in tree planting, one you can’t meet by heavily amending the backfill.

Finally, fashion a circular earthen moat around the new tree at a radial distance from the trunk that includes several inches of native soil (when watering, you must saturate the backfilled soil and some native soil). Finally, water enough to fill the moat area, checking for leaks.

As the backfill soil compacts under the effect of the watering, it may be necessary to add soil to bring the rootball, backfill and native soil into line.

Mulching

Nothing improves the chances of transplant success as cost-effectively as mulching. Mulch retains soil moisture, moderates soil temperature and eventually adds organic matter to soil. Add two to three inches of mulch (just about any reasonably coarse, organic materials works—wood chips, bark, nut shells, etc.) over the area within the tree moat. The only precaution: Don’t let the mulch cover the sensitive area where the trunk meets the soil.

Watering

The best way to water a newly installed tree is by bucket. Drip irrigation is a convenient but fallible alternative. And the best amount and frequency to water a newly installed tree…depends on the structure of your soil, the evapo-transpiration rate during a given week, wind velocity, and so on and on and on. Another formula helps. Chicago’s Morton Arboretum recommends watering a transplanted tree at a rate of five gallons per inch of trunk diameter per week. So in Illinois, you’d measure your transplant’s trunk diameter (4.5 feet above ground), multiply by five and give it that amount each week. But since we’re a long, long way from Illinois, the Santa Fe watering formula is more like seven or eight gallons per inch of trunk diameter per week. If it’s really hot, use eight to ten gallons per inch per week. If your tree gets ten gallons per week, it’s a good idea to apply five gallons on, say, Sunday and another five on Wednesday. If it’s really, really hot, you might water three times per week, increasing the volume by 25 percent or so.

Adding a transplant shock inhibitor/root stimulator like Superthrive once a month is a must. No one knows what’s in Superthrive but every professional arborist knows of its efficacy.

Transplants should be watered at least weekly from mid-March through mid-October and then at least monthly through the winter. In their second year, new trees should be watered every ten days during the growing season and at least monthly through dormancy. Third-year transplants will require supplemental watering at least every 14 days during warm weather and every month in winter.

The bigger the tree gets the more water it will need. And the irrigated area must increase every year. There's no “plant it and forget it” tree in Santa Fe. There are only good years, when rain and snow take some of the sting out of your water bill, and bad years, when even the healthiest looking, long-established trees can succumb without our help. The more we know about the needs of our arboreal treasures, the easier it is to preserve their health and beauty.

Rich Atkinson - The Treeman - is a certified arborist and owner of Southwest Trees. He is a long-time member of Santa Fe Botanical Garden and a former director on the Santa Fe Botanical Garden Board.

Visit www.santafebotanicalgarden.org to learn more about how Santa Fe Botanical Garden celebrates, cultivates and conserves the rich botanical heritage and biodiversity of the region.