originally published: February 2020

Garden Guru: More About Trees

by Matie Belle Lakish

Last month I talked about the importance of trees in long-term storage of carbon, and how even the roots can help with this planet-critical function. A high-mountain desert is not an easy place to grow trees, so I want to share some thoughts on choosing and caring for trees in our climate. My focus will be on fruit trees, but the same techniques and principles apply to most other trees, as well.

Select cold-hardy varieties. Over the years that I have lived here, the climate has gone from a Zone 3 to a Zone 4 growing zone, with average low temperatures of -20 to -25. Those are averages, however, and when dealing with trees that have lifespans in decades, we may encounter years where the temperature dips well below average. Look for trees that can withstand temperatures down to at least -30, or those that state a hardiness to at least Zone 4, preferably Zone 3. In addition to hardiness zone, consider your specific growing conditions. Are you on a slope, where cold air may drain away? In a pocket where cold air collects? Out in the flat areas where cold air settles? These factors can make the difference of a zone or two.

Many of the nurseries in Colorado are focused on trees for the Front Range. Most of these areas, including Salida, are closer to Zone 5, because they are at lower altitudes. Some trees sold by Salida nurseries will do well here, others will not be cold-tolerant enough. I find it helpful to search a few websites to see what they have to say about a tree I am considering. For instance, I have a Veteran peach that I planted a few years ago. In searching for it online, I find it is an old variety, and considered very hardy. A nursery in Longmont, The Tree Farm, (TheTreeFarm.com) says it is hardy to zone 5 and 7,000 ft. Other sites list it as zone 4. So far, it has done well here. Another peach that has done well is Contender, especially if planted in sheltered places, such as against a wall, out of the wind. With peaches, native to warmer climes, sometimes it is a gamble.

A word about the prunus fruits, including plums, cherries, apricots, peaches, etc. These fruits are known to attract a variety of aphid that also attacks potatoes, and are therefore considered a danger to the potato industry in the valley. I have noticed that aphids are attracted to prunus trees, so I can understand the concern. However, I don’t believe we have any potato fields within many miles of Crestone. Encouraging lady bugs can be helpful for aphids, as they and their larvae are voracious aphid eaters. Spraying with a soap solution can also inhibit them.

Of fruits, apples tend to be the hardiest, and the easiest to grow in our area. Some of the oldest hardy varieties, such as Haralson, Wealthy, and Macintosh have been growing here for decades. Some newer ones, such as State Fair and Honeycrisp do well also. When choosing an apple, you will want to consider a pollinator, as most are not self-pollinating. For instance, Honeycrisp blooms later than some other apples, and requires a late-blooming pollinator. Golden apples are recommended. I have noticed that not all nurseries discuss pollinators in their on-line and catalog information, making this another research question.

Of seed companies, I have found Jung’s, a Wisconsin nursery, (jungseed.com) to be consistent about discussing pollinators. They also tend to have hardy varieties, many from Canada. Two years ago, I ordered some columnar apples from Jung’s. These trees grow a single trunk with some small side branches, but are basically upright trees that don’t spread much. So far, the three that I ordered have done well. The ones that I planted against a stucco wall put on fruit the first year. Time will tell, but these may be a good choice for tight spaces, or for clustering together when you want multiple varieties. All three were listed as hardy to zone 3.

A favorite nursery of mine is Schlabach’s in upstate New York. Unfortunately, this Amish family farm does not have a web presence. I discovered them first when I was looking for a fabled Montrose apricot several years ago. This tree is reported to be quite large, and growing for decades in Montrose, Colorado. It is famed for frost-tolerant blossoms and edible-kernelled seeds. Schlabach’s has the plants listed in their new catalog, but in limited quantities. Most of the trees I have ordered from this nursery have been high quality and reasonably priced, and they have many antique apples, as well. Reach them at 2784 Murdock Rd., Medina, NY 14103.

Tooley’s Trees from Truchas, NM (tooleystrees.com) has come highly recommended for trees well adapted to our area. They are located in New Mexico between Taos and Santa Fe at a similar altitude to Crestone. Check out their extensive list of apple trees and a video they posted that demonstrates the proper way to plant and mulch young trees. Very helpful for new orchardists.

Young trees need to be protected, from all kinds and sizes of critters that live in the mountains. While some of the insect and disease pests that affect trees at lower altitudes are not as much of an issue here, we can sometimes import them when purchasing plants. For instance, many plants sold in local nurseries were grown and potted in places like Oklahoma, where soil pests, like borers, proliferate. Borers can destroy a young tree by girdling it. For that reason, I prefer to buy bare-root plants, so I can see what is going on with the roots.

Once your tree is planted, the larger critters come out. Mice and rabbits will chew the bark of young trees and may girdle them, preventing sap from flowing into the leaves. Protect them by putting a barrier of flexible plastic or metal hardware cloth around the lower part of the trunk. This is especially important during winter when rodents are hungriest. Deer will love the leaves and branches, if they can get to them, and bears will be attracted to the fruit. An ordinary six-foot fence will deter deer, but bears may require electric fencing. Pocket gophers are known to attack the roots of trees, and rock squirrels, as well as tree squirrels, love to pick the ripening fruit and eat the pits, which are nuts to them.

Fruit trees will benefit from occasional pruning. Young trees should be pruned to create proper growth shape and density of branches. Older trees will benefit from pruning for fruit production, as well. Colorado State University has a good on-line guide, at https://extension.colostate.edu/topic-areas/yard-garden/training-and-pruning-fruit-trees-7-003/. February and early March is the best time to prune trees. If you need help shaping and pruning your young trees, give me a call.