Fall is the best time of year to plant a new tree in Seattle. Trees planted in October-December benefit from our fall and winter rains, developing a stronger root system before the next summer dry spell.
If you're hoping to plant a tree this fall, we encourage you to think about the following questions:
Why am I planting a tree? Is it to add shade in summer, create a privacy screen, or simply add beauty? Answering this question will help you select the right tree to fit your purpose.
What site factors will influence my tree selection? Be sure to think about how much available space you have, the surrounding structures like your house and fence, overhead power lines, and undergound utilities.
What is the right tree for my site? The key is right tree, right place. Consider the size at maturity, tree shape & form, whether you want a tree that is deciduous or evergreen, and whether the tree is approved for planting under power lines.
Learn more about selecting the right tree and planting location here.
How to Plant a Tree
Below are 10 easy steps you can follow to make sure your tree gets the right start in life.
1. Call Before You Dig. Make sure you call 811 or submit an online dig ticket at least two days before planting. Make sure to plant your tree at least 5 feet away from any marked utility lines. Note: your sewer line will not be marked by calling 811. Use this tool to locate your side sewer line and stay at least 5 feet away.
2. Remove the tree from the pot. Gently roll the pot from side to side on the ground then tip it upside down. Be sure to carry/move the tree by handling the pot, not the tree's trunk.
3. Locate the trunk flare. Remove any excess soil piled on top of the root flare. The trunk flare is the area where the first major roots extend out from the trunk (see photo). Once planted, the trunk flare should sit just above the top of the soil.
4. Examine the roots. Roots that are circling should be redirected to grow out into the soil. If this is not possible, it is better to cut a root than to allow it to continue growing in a circular fashion. Circling roots will stunt the growth of the tree and can eventually lead to the tree’s death.
If the tree is really root bound and the roots are circling around the edges of the container, cut an X across the bottom of the root ball and then 4 vertical slices along the sides of the root ball with your sharp edged trowel or hori hori.
5. Dig a shallow, wide planting hole. Dig the hole only as deep as the root ball and about 2-3 times as wide. Do not loosen the soil at the bottom of the hole, which will cause the tree to settle over time. If you are removing turf, knock any loose soil off of the turf and in to the soil pile for re-filling.
6. Remove any bamboo stakes or tags still attached to the tree. These will not help support your new tree, and will only cause harm to your tree down the road.
7. Place your tree into the hole and orient. Think about where you want the main branches to point. Be sure the trunk flare is aboveground. A buried trunk flare will lead to rotting over time, compromising the health and safety of your tree.
8. Fill in the hole using the native soil and pack in firmly. Avoid putting amendments such as fertilizers and compost in the hole. These can actually harm your tree. Amending is best done with a thin layer of compost as a top dressing.
9. Water your tree in. Give your new tree a nice drink of water and help remove excess air pockets.
10. Mulch. Spread 2-3" of bark mulch or arborist wood chips around the base of your tree, keeping it about a handswidth away from your new tree. Learn more about the importance of proper mulch.
Stake only if necessary. Stakes can rub and cause damage to the bark and branches. Stake your tree only if the tree cannot remain straight without support. If you do decide to stake, use broad, flexible tree ties to attach the tree the stake. Find the lowest point on the trunk where the tree can be held upright. This will let the trunk move with the wind and build stronger roots. Use broad, flexible ties and keep the ties loose on the trunk to avoid girdling. Remove stakes after one year. Learn more about proper staking here.
Watch this tree planting video to learn more:
Selecting a Healthy Tree from the Nursery
Planting healthy trees starts with selecting a healthy tree from the nursery. Look for a tree with:
A strong well developed single leader (trunk).
Good branching structure with branches distributed around the trunk. The branches should be smaller in diameter than the main trunk.
No large circling roots present on the surface of the container. Since container trees are often planted too deeply in their container, you may want to dig down and look for large circling roots under the soil.
Avoid trees with lots of weeds or moss growing on the surface of the soil. This can indicate the tree has been in its pot for a long time and may be root bound.
If the tree still has its leaves, examine the leaves and make sure they look healthy. Remember if it is fall, it is normal to see browning or yellowing leaves.
Bright, healthy looking bark.
A trunk and limbs free of insects or wounds.
A visible root flare. Since container trees are often planted too deeply, you will likely need to dig down to locate the root flare, which is where the first major root extends from the trunk.
Look to nursery staff for help. Nursery staff are full of knowledge and want to help you. Ask them questions about the trees you see and tell them what you are looking for.