Author: Ken Diebel, Riparian Specialist, Oregon Department of Agriculture
Publish Date: Winter 2010
Planting trees is like raising kids. It is a long-term commitment. This is particularly true along streams. The riparian area, as scientists call the narrow band next to creeks, is a dangerous place for a tree or shrubs. It is full of weeds and animals that will choke out or kill woody plants we may want to grow there.
While there are challenges, you can successfully establish trees and shrubs by following proper procedures. Keep in mind this is only an outline. Contact OSU Extension, your local Soil and Water Conservation District or Watershed Council, the Oregon Department of Forestry, and the Natural Resources Conservation Service for more detailed assistance.
Know Your Creek
How often does your creek flood? Does it run dry by the end of June? Are the banks stable? Or are they constantly peeling off and falling into the water? Knowing the answers to questions like these will help you determine the kinds of species to plant. Some will tolerate frequent flooding while others are better able to withstand drought.
If your banks are unstable, you might consider forgoing planting until you stabilize them. Too often people plant trees on vertical banks only to have the stream erode the soil right out from under the plant.
Put the Right Plant in the Right Place
Most people would not plant a redwood in the desert. That may sound ridiculous, but planting a pine in a bog is just as bad, but it happens. Matching plant species to your site takes some research and thought.
An important step to selecting the right species is to find out as much as you can about the soils along your creek. The Soil Survey, available from the Natural Resources Conservation Service, has a detailed description of soil types, and general guidance for suitable vegetation to plant in your area.
Another consideration is picking a species adapted to the seasonal pattern of moisture levels. Plant water-loving species, such as willow, in the area closest to the creek. Further away, where it is only seasonally flooded, plant species like dogwood or cottonwood. Pines should only be planted in relatively dryer places.
Like a boy scout, a good tree planter’s motto is “be prepared.” Map out where you want to plant. Look up. Power lines may be rare out in rural areas, but they are there. It is a shame to have to cut a perfectly healthy tree just because it has grown into a power line.
Have all the equipment you need to plant ready and on hand. Planting your trees immediately will greatly increase their survival. If you have to store your seedlings, keep them cool and moist.
Plant It Right
One of the easiest challenges to overcome is simply planting the seedling or cutting it correctly. Too often, this straightforward process is neglected. If you are using rooted plants one of the most important considerations is keeping the roots from drying out. It takes only a few minutes for damage to occur.
Another common mistake is to plant a willow, or cottonwood cutting with too much left above ground. A general rule is to put 75 or 80 percent of the cutting below ground. This enables the plant to develop an adequate root system to support the above-ground leaves and branches. Plants know about gravity. It is important to plant a cutting with the buds pointing up. One of the ways to overcome some of the problems with lack of moisture late in the summer is to plant as long a cutting as possible. This will help keep the roots within reach of subsurface water. OSU Extension has several publications to guide you with proper tree planting techniques.
Take Care of Your Trees
A recent assessment of riparian plantings in Union County Oregon revealed that proper maintenance is critical for success. Statewide assessments have come to the same conclusion.
Weeds and grasses not only compete with trees and shrubs for moisture, light, and nutrients, but they also provide cover for rodents. These rodents will chew on the bark and roots of woody plants killing them.
In your plans for planting your riparian area, include some means of controlling competing vegetation. Using plastic weed mats is one alternative. Mowing and or spraying are other possibilities. Check to ensure the chemical you plan on using is acceptable for use around streams.
Irrigating your plants during the hot dry months does help, but consider this option carefully. If your stream runs year-round, and you have planted the right species in the right place, you probably won’t need extra water.
Seedling Care and Planting
Plant Your Trees Right. Oregon State University Publication.
Bennet, M. and G. Aherns. 2007. A Guide to Riparian Tree Planting in
Southwest Oregon. Oregon State University Extension Publication.
Natural Resources Conservation Service
USDA Plant Database