Some proper planting will let your soil work for you

September 21, 2011 

Fall is for planting, and the end of September and the month of October are prime planting times for Western Washington landscapes. The great dirt-cheap news is that local nurseries have some of the best prices of the year on trees, shrubs and autumn color. All this plus the wet winter weather ahead means you won’t be a slave to watering any our newly planted specimens.

Before you add new plants learn these lessons of proper planting. These rules make your soil will work for you so your new plants will be drought-resistant and as well as bargain-priced.

When adding woody plants such as Japanese maples, burning bush, evergreen shrubs and shade trees follow these guides:


Don’t add compost: Skip the compost and don’t amend the native soil when you dig a hole for new trees and shrubs. (Yeah, I know this is a new rule.) Adding compost in the bottom of a planting hole can work like a well in our wet climate to hold too much water during the winter weather and rot the roots of the new plant. Instead, concentrate on digging a hole that is shallow but wide. Dig down 18 to 24 inches breaking through any clay or hard pan. The goal is to just loosen the soil and remove any big boulders or rocks larger than your fist. Make this hole at least three feet wide so the new roots will spread out and seek water on their own.

Don’t do the stomp dance: Once the tree or shrub is set into the planting hole, you can backfill using the same native soil you removed from the hole. Firm the soil around the base of the plant with your hands. Do not stomp on the soil around a new plant. This pushes all of the air pockets from the soil profile. It is rather rude to the soil, and the result could be dancing on the grave of your new plant.

Don’t loose the crown: Woody trees and shrubs have a bump or ridge where the trunk meets the soil. Make sure this crown is a few inches above soil level. Planting trees and shrubs too deep – especially shallow-rooted rhodies and azaleas — is a common cause of a slow and painful suffocation. Scrape away the soil and mulch if your rhodies are suffering. They may just need air.

Add a well for rain water: You need to build a slight depression with a rim using soil around the base of your newly planted trees and shrubs to catch rainwater. This is especially important the first year.

Feather on the mulch: After planting, you should add a mulch of Moo-Doo, bark or wood chips at least two inches deep – but don’t allow this mulch to touch the crown of the new plant. This is especially important for rhododendrons and dogwoods that suffer from root rots when the mulch is allowed to pile up around the trunk. The technique called “feathering” is to make sure that the mulch is two to three inches deep a foot or two away from the trunk but apply less mulch as you move closer to the crown of the plant. The layer of mulch nearest the trunk should just barely cover the native soil.


Loosen the soil: Most perennials do best in well-amended soil, which means you can loosen the soil to a depth of one foot or more, and then work in a four-inch layer of compost or manure. Loosen and amend your soil a week before you add new plants and it will be nicely settled, but still fluffy.

Get a head starts: Fall planting of perennials gives them a robust start in the spring and this is also a good time to add spring blooming bulbs, such as daffodils and tulips, and hardy summer blooming bulbs such as lilies. The secret to happy perennials is mixing the good stuff like compost evenly and deeply into the top foot of topsoil – don’t just add a shovel full to the bottom of the planting hole – mix it in.

Don’t stomp: As with trees and shrubs, don’t stomp on the soil around new perennial plants, create a slight depression to catch rainwater and mulch very lightly near the crown of the new plants but more deeply as you move away from the plant.

Critter watch: One last tip for perennial planting this fall – bait for slugs.

Marianne Binetti is the author of “Easy Answers for Great Gardens” and eight other gardening books. She has a degree in horticulture from WSU and will answer questions from her website at

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