Evergreen Fact Sheet No. 7.403 Gardening Series | Trees and

James Klett and Lisa Mason (10/2020) Quick Facts Most evergreens prefer Narrowleaf evergreen () trees Selection full sun; some will give a landscape year-round interest, Examine the intended planting space tolerate partial shade. color and texture. Conifer trees are for good soil drainage, adequate versatile and can be used as When selecting sunlight and sufficient space to specimens, hedges, privacy screens, evergreens, consider accommodate the desired evergreen backdrops for smaller flowering , available space, soil at its mature size. Allow for clear and site conditions, and or as a windbreak planted on the north access to driveways, sidewalks and weather factors. and west to deflect or intercept winter entryways. Determine whether the tree’s winds. (See fact sheet 7.225, growth will affect any overhead utility Evergreens have Landscaping for Energy Conservation.) lines. Before planting, call the utility different soil moisture companies’ hotline (dial 811) to mark preferences. Group “Evergreen” refers to trees that drought-tolerant types the location of any underground lines to normally retain most of their foliage separately from those avoid damaging them while digging. For (needles) through the winter. Such that require more other considerations on species trees, however, do not retain all of their moisture. selection and location, refer to CSU needles indefinitely. For example, Extension Garden Note #631 Tree All evergreens benefit ponderosa drops needles each Placement: Right , Right Place, from mulches. All need year that are three years old. These and #632, Tree Selection: Right Plant, sufficient water to older needles are the innermost ones Right Place. become established toward the main trunk. Younger after transplanting. needles, further out on the branch, are In smaller sites, consider smaller retained until they are three years old. Most evergreens trees or shrubs. (See 7.418, Small This annual browning and drop of benefit from Trees, 7.414, Evergreen innermost, older needles can cause supplemental water Shrubs, 7.415, Deciduous Shrubs, or during dry, warm or concern, but it is a natural process. 7.427 Columnar and Fastigiate Trees for windy periods from CO Landscapes). Consider dwarf November to March. for limited space areas. If there is sufficient space, use several kinds of J. Klett, Extension Specialist, Colorado State University; evergreens to add variety to the and L. Mason, Horticulture landscape. Agent, Colorado State University Extension. R. A. Cox, Retired Horticulture Agent, Colorado State University Extension contributed to the original version of this fact sheet.

Above: A Colorado blue in Bristlecone pine trees have needles in groups White cones stand upright on the branches. winter. Photo: Lisa Mason (fascicles) of five. Photo: Lisa Mason Photo: Robert Cox extension.colostate.edu 1 © Colorado State University Extension. 04/05. Revised 10/20. Watering and Maintenance For gardeners above 6,000 feet, some of the plants listed in Table 1 are not adapted. Refer to 7.423, Trees The following list (Table 1) indicates the relative and Shrubs for Mountain Areas for specific moisture needs of evergreens. Plant species with similar recommendations. Refer to 7.421, Native Trees for water needs in the same general area – do not mix trees Colorado Landscapes and 7.422, Native Shrubs for with widely different water needs. Colorado Landscapes for native evergreens. Evergreens that need less moisture may work well on slopes. All evergreens usable in Colorado prefer well drained soils. Avoid planting them in swales or poorly Planting Evergreen Trees drained, soggy areas. Evergreens that need less Growing a healthy evergreen tree begins with proper moisture may not do well in lawn areas because of the planting techniques. Mistakes such as planting a tree amount of water needed to sustain the lawn. Even for too deep are common in the landscape, and lead to those trees that need more moisture and are compatible trunk-girdling roots which can shorten the life span of with lawn watering, leave the planting area free of sod to the tree significantly. Proper planting techniques allow for good root development. An organic mulch is promote rapid root growth while reducing water recommended over the entire planting area. (See 7.214, stress from the harvest and planting process. For more Mulches for Home Grounds, and CSU Extension Garden information, refer to CSU Extension Garden Note #633, Note #658, Mulching Trees). The Science of Planting Trees, #636, Tree Planting Steps, #635, Care of Recently Planted Trees, #634, Most evergreens growing in Colorado landscapes, Tree Staking and Underground Stabilization, and fact whether recently transplanted or well-established, sheet 2.926, Healthy Roots and Healthy Trees. benefit from supplemental water during winter dry spells. Often, such spells are accompanied by drying winds or unseasonably warm temperatures, further emphasizing the need for watering. (See 7.211, Fall and Winter Watering, CSU Extension Garden Note #657, Watering Mature Trees, and 7.240, Watering a Home Landscape During Drought).

Table 1. Recommended evergreen trees for Colorado.

2 © Colorado State University Extension. 10/20. 3 © Colorado State University Extension. 10/20. 4 © Colorado State University Extension. 10/20.