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written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
published 10/11/13

I often get asked when is the best time to plant or transplant trees and shrubs. It’s a question that I have to answer with, “it all depends.” Mid-fall, after trees and shrubs are dormant, can be a good time to plant or move trees and shrubs.

There are several reasons why fall planting is frequently recommended. One reason is that the soil temperature is warmer in fall than in early spring. This is an advantage because roots of woody plants will grow when the soil temperature is above 40 degrees. This allows fall planted trees and shrubs to become established before the stress of summer heat next year. When planted in early spring, roots don’t have as much time to grow and adequately support the plant when hot weather arrives.

Another reason for recommending fall planting is that as plants go dormant in autumn, there is less competition for the carbohydrates needed for growth. In the spring, carbohydrate reserves are needed for both top growth and root growth. This results in a fight between the roots and the top of the plant for those reserves.

If you are considering moving a tree or shrub that is already established in your landscape, fall is the best time to do this. The stress caused by the root damage and the shock of moving the plant will be less when done in the fall when the plant is dormant. The most important thing whenever moving a plant is to get as many of the roots as possible. It is estimated that when woody plants are dug up in a nursery as much as 95 per cent or more of the root system is lost. It is likely that even more roots are lost when we move landscape plants.

Those were the “pros” for fall planting, but there is one significant “con” or reason against it. Water. Fall planting is great for the regions of the Pacific Northwest that can depend on natural fall and winter rains to keep the soil moist. We can not. Fall transplanted trees and shrubs should be watered in with a thorough watering at planting time and then the soil should be kept moderately moist to help the roots grow.

If you plant or move a woody plant in the fall, you must find some way to provide it with water through the fall and winter months when the weather is mild and dry. Hauling out a hose during the winter is a nuisance, but the advantages gained by fall planting will disappear if the soil is not kept moist. Check the soil regularly to monitor the moisture situation even when foggy and overcast weather predominates.

I also recommend that you mulch your newly transplanted tree or shrub with a three to four inch layer of shredded bark or wood chips to help retain soil moisture and discourage weed growth next year.

Fall is a good time to take advantage of sales held by local nurseries to reduce the volume of woody and perennial plants they need to hold over the winter. However, before you buy make sure you have a suitable site where you can provide water through the fall and winter months.

Published: 10/11/2013 2:05 PM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

If you want to plant trees in your landscape now is a great time… while conditions are mild and the trees are still dormant.

The first step in planting a tree is digging a hole to accommodate the root system. There is something satisfying about digging a good, deep hole… but that Adeep@ hole can lead to a tree=s demise. Dig the hole for your tree only as deep as the height of the roots and twice as wide (or more) than the diameter of the root system. The roots at the top of the root system should be planted so that they are just below the soil surface. When you dig a deep hole, the roots often end up well below the surface of the soil because of the settling that occurs after planting and watering.

If your tree was grown in a container, the next step is to remove it from the pot and carefully shake the potting soil off the roots. Many container grown trees have Apot bound@ roots. To remove the soil from these you may need to wash it off in a large bucket or trough of water… or hose it off with water. Once the roots are revealed, loosen them with gentle teasing… or they may need more aggressive persuasion involving physically straightening them or pruning off woody roots that are extremely kinked or encircling. You now have a Abare root@ plant and it=s extremely important to prevent the roots from drying out. Plant it immediately or keep the roots moist.

Place the tree in the hole, positioning the roots over a mound of soil to help steady the tree while you refill the hole using only the original soil from the hole that you dug. It=s not necessary or desirable to add any type of compost or soil amendment to the backfill soil.

Next water the tree to settle the soil around the roots. I like to stick my hose with a gentle flow of water right down into the soil. The hole will fill with water and the soil will settle in, eliminating air pockets. After the water drains out of the hole, you can add more soil to finish filling the hole and gently firm the soil around the roots with your hands. (No stomping!) Pay close attention to watering your tree for at least the first year or so after planting, keeping the soil evenly moist. Dry soil or wet soil conditions will impair the ability of the tree roots to regenerate. Finally, mulch the tree with a coarse organic mulch such as bark.

ABalled and burlapped= trees are those that were grown in the field and then dug for selling. The roots and soil around them are covered with burlap that=s often held into place with twine or wire baskets. Remove all burlap, twine, wire and any other materials around the roots. The soil around the roots is often a heavy clay that you should get rid of as recommended earlier using a water bath or hose. If needed, straighten and prune roots and then plant in the same way as indicated before.

These new recommendations from horticultural experts are not well accepted by nurseries. Few, if any, will guarantee their stock if you remove the burlap or tease apart the root ball. However, your tree has a much better chance of surviving past the first year of its life if you follow this new way of planting trees.

Published: 3/10/2007 10:28 AM



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