Why do we plant in the fall? Planting season in the Pacific Northwest coincides with rainier weather and cooler temperatures, meaning that new plantings get plenty of water, and their growth slows down so that they can get settled in their new home and establish their root systems before their first dry summer hits. There are also some great sales to be found at nurseries in September! Fall planting is delayed gratification, since you won’t see much growth until the following spring, but it’s much easier on the plants, and you’re rewarded with budding, happy plants once the weather warms up, while your neighbors are out there paying full price, working in the sun, and driving up their water bills.
Planting at the right time of year helps give plants the best chance of success. So does planting correctly. In our restoration projects, some of our native trees, if they’re lucky, can live for hundreds of years out in our parks. So it’s worth taking a few extra minutes to plant them well. Here are our top tips for planting season, that might be helpful in your own home planting projects too. Happy planting season!
- Don’t dig too deep.
Even though they need their roots underground, plants don’t like their other parts to be buried by soil. Planting too deep can cause stems (so fragile in very small plants) to rot, and prevents necessary air flow. Filling extra soil back into the hole after you realize you dug too deep means that your plant is sitting on a loose, churned up foundation and is likely to sink as soil underneath it settles over time. Instead, measure periodically as you dig and stop when you’ve gotten to the right depth. When you are finished, the root flare (or root collar) of your plant – the widened base of the main stem just above where the roots start – should be visible just above the ground. If your plant was in a pot before, dig a hole exactly as deep as the pot, try to leave the plant in the ground at the same depth that it was in its former pot.
- Dig wide.
While you don’t want to dig too deep under your plant, you do want a nice wide hole with plenty of room for all of the plant’s roots to spread out on all sides. Loosening up the soil around the plant also allows lateral (sideways) roots to grow easily. If your plant was in a pot, dig a hole that is twice as wide as the pot.
- Leave a mulch doughnut.
Mulch can be anything you put on top of the soil after you are finished planting: wood chips, bark, compost, or fallen leaves can all make good mulch for different kinds of plants. The right mulch for your plant helps keep it from drying out, keeps in warm in cold weather and cool in hot weather, and adds nutrients to the soil. But you don’t want anything that can rot to be anywhere near your plant’s roots! So keep mulch, and any leaves and sticks, out of the hole you dig to put the plant in, and don’t add mulch until the very end when your plant’s roots are all covered up. When you’re finished planting, your mulch should look like a nice doughnut around your plant. Just like you don’t want to bury your plant too deep, you also don’t want mulch touching the main stem of the plant itself, because that can cause it to rot too. Pull the mulch a few inches away from the plant to let air to flow all around the main stem, leaving a thick ring on the surface of the soil, on top of where the plant’s roots are.
- No J-roots or girdling roots.
Make sure you lay the roots of your plant out in the bottom of the hole so that they spread out and down. Roots that are pointing up underground (making the shape of the letter J) are bad for the health of the plant. Roots that wind around the hole, encircling the plant, will keep growing around and around – these are called girdling roots because they can strangle other roots. If you have J-roots or girdling roots on a plant that you take out of a pot, and they are too stiff to straighten out in your planting hole, it’s better to cut them before putting the plant in the ground, as long as it is a side-root. Never cut a tap root or the main connection from your plant’s stem to the rest of its roots.
- Right plant, right place.
Don’t ever plant invasive species! Plants that “escape” from people’s yards through fragments, suckers, spreading vines, or seeds carried by birds or the wind, eventually end up in our parks and other public lands, where they threaten our natural habitats. Choose from a wide variety of beautiful native plants, or non-invasive horticultural species, that will stay in their own space. Also make sure you understand how big your tree or large shrub will grow and how long it will live, so you can plant it far enough away from power lines, foundations, and other things it might encounter as it grows, or pick a species that stays small enough to plant closer.
Want to put these tips to good use? Sign up to help out on Green Seattle Day, Saturday, November 8th, as we plant the future of our forested parks! Or, if you live in Tacoma, Redmond, Kirkland, Everett, or Kent, check out upcoming volunteer opportunities closer to home.