Selecting, planting and caring for a new tree

Buying a tree is an important decision

Although you may be buying a tree to add beauty to your home landscape, trees also serve other important functions in your landscape. For example, did you know:

• Proper placement of trees can reduce heating and cooling costs by as much as 10% to 20%
• Landscaping your home can increase the value of your property. Houses with mature trees sell from 6% to 12%percent more than houses on lots without trees.
• Trees and shrubs conserve water air, and soil and provide habitat for wildlife. Shade trees provide living, nesting, and gathering places for many birds and animals and offer shelter year round. Trees and other plants with abundant fruits and seeds are particularly attractive to birds.
• Large shade trees acts as an outdoor "ceiling" and give a more intimate feeling to your yard and street. Trees and shrubs can block an undesirable view, enclose an area for privacy, or separate on area from another.
• Trees also cleanse the air by absorbing carbon dioxide and giving off oxygen, which all organisms — including people — need to survive.

Your local nursery or landscape professional can help you consider plant characteristics and environmental factors to design a functional, attractive landscape. Remember that your own satisfaction with the trees and design is most important. You, more than anyone else, will care for and enjoy this tree.

A landscape plan for your yard

Before buying, think about what you need and where it should go

Consider your planting site carefully. Keep in mind that planting trees on your property affects your neighbors. And while a property located tree can increase your property value, planting the wring species, or even the right species in the wrong place, can lead to frustration and costly replacement, Even the best tree will not contribute to your landscape if it is planted in a unsuitable place.

So, before you decide what to plant, decide where to plant. Let the planting location dictate the tree species your select, rather than the other way around. Often people decide on a certain tree species, then have difficulty finding a place for the tree. If you have your heart set on a particular species, carefully seek out a suitable location for it.

Cold hardiness zones

Oregon is geographically diverse state, blessed with mountains, deserts, valleys, and coastlines. Some areas of the state are dry, while other receive abundant rainfall. Where you live affects the types of trees you can plant and expect to flourish. For example, a tree that grows well in the Willamette Valley may struggle to survive in Eastern Oregon.

The U.S. Department of Agriculture Hardiness Zone Map show the ratings assigned to various microclimates within Oregon.

Hardiness zones are based on the estimated minimum temperature in a given area. Trees found in the nursery or garden center are rated to a cold hardiness zone or degrees above or below 0°F. Use this map to determine the cold hardiness zone for your area.

A changing climate

When selecting a tree, you may need to account for weather conditions 20 to 30 years into the future. The U.S. Global Change Research Program says that average temperatures could increase by at least 2 degrees and up to 15° F by the end of the century, depending on future greenhouse gas emissions levels.

Winters are expected to become wetter and summers drier. Consider a changing climate and select plant species that can adapt to evolving conditions.

Points to consider about your planting site:

Does the site provide enough room for the tree's crown and roots to grow? Are the prevailing winds and sun exposure conducive to its growth?

Consider other trees, buildings, or landscape features near the site. Again, keep in mind the mature height of the tree you’re about to plant. What looks like enough room now may look very crowded after 10 years of growth. Tree roots need space too, and don’t like to be confined by sidewalks, driveways, or house foundations. Some trees tolerate shade, others prefer full sun. Some trees have shallow root systems, so you may need to stake the tree for the first year.

Are there utility wires or other obstructions nearby or overhead?

If there are overhead wires on your property, avoid planting large shade trees within 25 feet of them. Planting large trees such as Douglas–fir or maples underneath power lines could cause power outages and increased maintenance costs. Eventually these trees will require severe pruning, which is not ideal for the trees' health. If you must plant directly underneath wires, select a tree that will be less than 30 feet at maturity.

What is the soil like? Is it composed of sand or clay? Poorly drained or well drained? Is there an adequate water source?

The health and vigor of your tree will greatly depend on the quantity and quality of the soil in the planting site, so investigate the soil before you plant the tree. Soil near houses tends to be highly compacted, a less-than-ideal growing condition. Tree roots need loose or uncompacted soil because they must have oxygen for growth.

If you have sandy type soil, add a fine planting compost to increase the water-holding capacity of the soil. This will help with initial root establishment in areas such as Central Oregon. For clay-type soils, add coconut coir or other fibers to lighten soil tilth and provide drainage. Peat moss is not being used as much, as it is not a renewable resource.

What function will the tree serve? Will you choose a shade tree, an ornamental tree, or a conifer? Should the tree serve as a windbreak or privacy screen?

The purpose of the tree is an important consideration. For example, if you’re looking for a privacy screen, a maple is a poor choice because it doesn’t hold its leaves year round. However, a cedar is ideal for this purpose. If the tree’s primary purpose is shade, an oak, maple, or ash may be at the top of your list.

How big is the tree you are planting?

Small trees establish quickly, but may take time to make a noticeable impact in the landscape. On the other hand, planting a large tree provides immediate effect, enhancing the landscape instantly. However, it may require a longer establishment period and increased care due to root loss during nursery transplanting.

Choosing the right species: What to look for in a tree

After considering what type of tree you need and evaluating your planting site, visit a nursery or garden center. Take your site plan with you. Look for a tree with good form and healthy leaves, with no damage to its trunk. The following list of tree types should help narrow your selection to the trees that best suit your reason for planting.

• Shade trees are deciduous, meaning their leaves turn color and drop off in the fall. They are best planted at least 25 feet away from houses, buildings, or other obstacles. Shade trees can range from under 35 feet to 50 or even over 100 feet tall at maturity. Avoid planting shade trees under utility lines or too close to other trees unless you plant a small species.
• Ornamental trees are usually chosen for a particular characteristic, such as spring flowers, fall color, an attractive bark, or crown form. These trees range anywhere from 25 to 50 feet tall at maturity. Small, ornamental trees work well under utility lines or in confined spaces. These trees should have a mature height of less than 25 feet. Ornamental trees are sometimes referred to as "exotics", but this term is better suited for trees growing outside of their normal environment, such as palm trees in Oregon.
• Conifer trees ("evergreens") have needles or needle-like leaves that usually stay green all year. Conifers are the best choice for windbreaks and privacy screens.
• Native trees are those that grow naturally in Oregon. Douglas-fir, ponderosa pine, Oregon white oak, vine maple, big leaf maple, and numerous species of spruce, fir, cedar, and other deciduous trees are native to Oregon. Native trees fit well in the home landscape, especially along streams or open areas, but might not be suitable for all sites and situations in urban areas.

Large-statured trees

When selecting trees for your property, consider planting large-statured trees to maximize environmental benefits. These trees offer greater ecological value than smaller ones.

However, if you are considering planting a tree that will grow large, assess space limitations carefully. Watch out for overhead lines, fences, neighboring properties and infrastructure like sidewalks and roads. Be sure you know the mature size of the tree before planting. Trees that will grow large are best planted in open spaces, away from structures.

Trees for tough sites

These trees do well in poor soils, urban conditions, or temperature extremes

Trees for fall color

These trees produce spectacular autumn foliage.

Trees for under utility wires

Low–growing species well–suited for under power lines

Trees for the Oregon Coast

These trees are suited to moisture and high winds.

Trees for spring flowers

These trees put on a show of color and fragrance in the spring

Trees for energy conservation

These trees help shade your home, reducing energy costs.

Trees for water conservation

These trees require little watering beyond early establishment.

Steps for planting container and balled-and-burlapped trees

Many problems with a tree can be traced back to improper planting. It’s important to dig a hole that is 2 to 3 times the width of your root ball but only deep enough for the root ball to sit 1 to 2 inches above ground level. A large hole will allow better root growth and is especially important in compacted soils. Roughen the sides of the hole, which should be the same width at the top and bottom, and remove any rocks or debris. Here is a step–by–step guide for planting both container trees and balled–and–burlapped trees.

Fertilizer and amendments

Amendments are additions to the soil that enhance its moisture-holding capacity, nutrient availability, or structure.

Amendments include good loamy topsoil, peat moss, and various kinds of mulches. Most soils in Oregon — except sandy soil, soil with a high clay content, or soil that has been heavily disturbed by construction — don't require amendments.

Sandy soil, often found in Eastern Oregon or along the Oregon Coast, benefits from the addition of organic matter such as cocnut coir to the planting hole to increase the soil's moisture-holding capacity around the roots.

Additions of organic matter also help clay soil. This soil is easily compacted, which obstructs the movement of water and air. Mixing in organic matter helps break up clay particles and improves water and air flow around the roots.

Construction equipment compacts soil and removes valuable topsoil. Additions of topsoil, peat moss, and other organic matter can improve a tree’s growth and survivability on construction sites. Compost may be too hot.

How much soil amendment should you add to the backfill? Generally a ratio of one–third amendment mixed with two–thirds of existing soil is sufficient. Use caution with composted materials, which may be very hot from biological activity or high in salts (manure is one example).

Contrary to popular belief, you don’t need to fertilize trees when you plant them. However, if you want, you can use a well– balanced (for example, a 10–10–10 formulation), slow–release fertilizer in the planting hole. Slow–release fertilizers have a long–lasting effect and are less likely to burn the roots. Other fertilizers can accentuate transplant shock. Never use lawn fertilizers in a planting hole.

Early tree care: How to keep your new tree alive

Newly planted trees require routine and thorough watering, particularly during Oregon's dry summer months. Water the tree regularly for at least 3 years after planting. Soil and weather conditions, as well as the amount of completing grass around the tree, dictate how much water to give and how often. In general, trees need the equivalent of 1 inch of rainfall per week from June through September.

Watering in winter

Remember that trees use water even during winter. Just before the ground freezes in late fall, give your tree a thorough watering. During mild winters, where temperatures are above normal and the ground thaws, give your tree periodic watering. This is particularly important for conifers, which retain their needles and use water readily during winter.

How to water

Before you water, examine the soil moisture 4 to 8 inches deep. If the soil feels dry or just slightly damp, it needs water. Well-drained, sandy soils will need more water more often than a loam or clay soil. The best way to water a newly planted tree is to place a garden hose at the base of the tree. Run a slow trickle of water for several hours or until the soil is thoroughly soaked. To help hold or direct the water around the root system, build a temporary soil berm or saucer.

Irrigated landscapes

In eastern Oregon, plant ornamental and shade trees in an irrigated landscape or hand water them regularly to ensure their survival, In drier regions of eastern Oregon, trees often need water during winter to prevent desiccation.

Mulching

Using a mulch around the base of the tree is an important part of long–term tree care. A mulch keeps the soil moist, limits weed growth, adds organic matter to the soil and discourages injury to the tree from lawnmowers and weed–eaters. Wood and bark chips are good mulching materials. Avoid synthetic mulches made from rubber or plastic. Stone or gravel isn’t ideal from a tree health standpoint, but may be necessary in firewise landscapes.

You can use a porous landscape fabric as a weed barrier underneath the chips, but don’t use plastic because it suffocates the roots. Apply a 3- to 6-inch layer of mulch and spread it to form a circle at least 3 feet away from the trunk. Keep the mulch from direct contact with the tree trunk. Some bark mulches may contain pathogens or contaminants that can harm your new tree. Maintain the mulch ring to keep grasses from competing with the tree, and enlarge the diameter of the mulch ring as the tree grows larger.

Do's and don'ts of new tree mulching

Pruning myths

Fertilizing new trees

Fertilize established trees (one year after planting) every two or three years in the fall after the leaves have dropped or in early spring before growth begins. Apply the fertilizer directly to the soil surface and water it in. If there is thick grass sod beneath the tree, use a pipe to punch holes 12 inches deep in the sod beneath the drip line of the tree and apply the fertilizer in the holes. This helps the fertilizer reach the tree’s root system. Avoid using “weed and feed” fertilizers around the root zone of your tree. Don’t apply nitrogen in late summer, because it can stimulate new growth that may not “harden off” or go into fall dormancy properly and will be more easily damaged by early fall frosts.

Monitoring your tree's health

Periodically inspect your tree for signs of insects, disease or other problems

If you aren't sure what's causing the problem, take a sample of the affected area to your local nursery of tree care professional of OSU Extension Service agent to see if they can diagnose the problem and prescribe a treatment.

Consulting Extension experts

Oregon State University Extension Service has offices in most Oregon counties. Some counties have a horticulture or forestry agent. In many counties, the OSU Extension Service coordinates the Master Gardener™ program, a training program for people interested in learning more about plants and trees. Master Gardeners are available by phone to answer your plant care questions, or you can use Extension's Ask an Expert service.

See whether your community has a program to plant and care for trees. Many Oregon cities have earned the status “Tree City USA” for having comprehensive community forestry programs. Contact your local parks or public works agency and find out how you can get involved in planting and caring for trees in your community. If your city isn’t a “Tree City USA” community, consider joining the effort.

Selecting an arborist

When the job is too big to handle yourself, call a professional. Some tips to consider:

• Hire someone who is bonded, licensed, and insured. Tree service companies must register with the state of Oregon, so ask for a contractor registration number.
• Ask for references and get more than one bid. Take your time and select a company you know is reputable.
• Ask for a certified arborist. Certified arborists are professionals with tree care experience who have passed the International Society of Arboriculture’s Certification Exam.
• Beware of door-knockers. Most companies have business cards, uniforms, truck signs, etc. Most reputable companies advertise and don’t solicit business door-to-door.
• A good arborist rarely recommends topping and should try to talk you out of it if you request to have a tree topped. Avoid tree toppers at all costs!
• Never allow a climber to use spikes or spurs to climb your tree unless the tree is to be removed.

For more information

Organizations

1. Arbor Day Foundation: The foundation publishes materials on tree planting and care.
2. Trees Are Good
3. International Society of Arboriculture: This consumer education organization features information on all aspects of tree care.
4. Oregon Community Trees: This organization promotes proper tree planting and care.

Recommended reading

Your local library or bookstore has many good books on tree planting and care. A couple we recommend are:

• The Complete Guide to Landscape Design, Renovation, and Maintenance. Betterway Publications Inc. 1991.
• General pruning techniques, North Carolina State Extension
• An Illustrated Guide to Pruning, Third Edition. Sengage Learning. 2011.
• The Practical Science of Planting Trees. International Society of Arboriculture. 2013.
• Pruning shade trees in landscapes, University of Florida IFAS
• Sunset Western Garden Book, Sunset Publishing Corp., 2012.

Acknowledgments

Some of the material in this publication originally appeared or was adapted from the Minnesota Department of Agriculture and the Kansas State University State and Extension Forestry program.