Plant like a pro

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!

Plant Drawing_one_line

  1. 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.

  1. 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.

  1. 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.

  1. 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.

  1. 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.


How did the invasive weeds get here?

Ivy - run for your life!

Many flowering invasives such as herb Robert and morning glory were planted by gardeners. Invasive knotweeds and English ivy were planted by landscapers for their ability to grow quickly and create natural fencing barriers. Non-native blackberry was cultivated for its fruit. Plants like the St. John’s wort were introduced for their medicinal benefits. Others such as Eurasian watermilfoil were accidentally brought across the oceans in shipments or carried on ship ballasts.

Whether they hitched a ride accidentally or were brought here on purpose, all of the invasive plants we remove at work parties have aggressively spread far beyond the expectations of those who originally brought them. The effects of this spread, unchecked by natural predators or conditions, now cause a major threat to the health of our native habitats here in the Pacific Northwest. To help restore these habitats to health in a city park or natural area near you, improving environmental functions such as stormwater control as well as caring for our valuable public greenspaces, volunteer with one of the Green City Partnerships.

Can I climb that tree to cut down the ivy?

While perhaps fun, this isn’t necessary. Instead we cut a survival ring for a tree. By clearing a 6 foot radius around the base of the tree and removing all the vines from the forest floor up to your chest height on the tree’s trunk, all the remaining ivy foliage in the canopy of the tree trunk will whither and die. The ivy’s weight is already stressing the tree enough without us crawling through its branches too. If ivy is wrapped tightly enough, pulling it out of high branches without cutting it first can further damage the tree.

Best management practices (BMPs) are created by restoration professionals and volunteers alike to most effectively address the challenges posed by each individual invasive weed species. See some other weed-specific methods at the Green Seattle Partnership website.

To practice the BMPs yourself and get your hands dirty for our urban forest and natural areas, come to a work party near you in Seattle, Tacoma, Kirkland, Redmond, or Kent!

Are we taking out the birds’ food?

Red-breasted nuthatch, photo by Ken Batker

The wildlife living within a plant community are used to the native vegetation.  Non-native species upset this natural harmony, so although birds often will eat Himalayan blackberries, they have happily feasted on the native blackberry, salmonberry, snowberry, huckleberry, elderberry, Indian plum, and thimbleberry well before the invasives came to our forests. We make sure to include these in the diverse array of native plants we select for our restoration sites. In addition to the fruit they produce, native plants help to re-establish a healthy functioning environment by preserving the natural hydrology, soils, canopy cover, and other elements of good habitat for local wildlife.

Better Than Goats?

The Goat Lady LLC's hungry goat munching on Scotch broom at Shiga's Garden

A: Goats can be a very economical, green, and fast way to remove invasive species and they are being used successfully in many places. A fellow AmeriCorp member recently utilized their help at her new community P-Patch, Shiga’s Garden. However, they have not proven ideal for our Green Cities Program.

The use of goats can be cost-effective in comparison to other hired removal techniques (aka paid human labor or machines), but they still cost money and take time to monitor. Also, the Green City Programs often work in areas where there are many important native plants that we want to keep alive and when employing goats, they are not as selective as our human volunteers. Also, goats can only eat up to their head height (~3 feet) and they aren’t able to dig up the roots, which for most invasive species (especially Himalayan blackberry) means a whole new crop will grow up in their place the following year!

This is why we rely so heavily on our human volunteers and it’s amazing what you guys accomplish in a short amount of time. In Seattle, volunteers have helped remove more than 400 acres of invasive species since 2005. The hard work & sweat you put into digging up those roots is the best way for us to combat these weeds. We are able to remove the roots of the plant, limit the amount of soil disturbance and erosion, leave native plants intact (which can repopulate), and replant with native species to help along the restoration process. Your hard work is our first and our best line of defense against these invasive species. We simply could not accomplish our goals without your help! Thank you volunteers!

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Blackberry Rootwad

Why does a non-native plant spread so quickly?

IMG_3006Non-native plants spread because they have no natural predators or competitors to keep their populations in check.  Oftentimes these plants have short reproduction cycles, produce many seeds or fruits, have seeds that remain viable for many years, and are happy living in the full range of climatic conditions, all of which help them dominate.

In contrast, the diverse array of trees, shrubs, and groundcover plants that make up our native northwest forest have grown here together for centuries. They have developed complex interactions and together they support each other, native wildlife, and a healthy, functioning, holistic ecosystem.

In many urban areas in the Puget Sound, a history of logging, development, and other human activity has degraded the seed bank of our native species, and left us with open spaces overgrown or quickly becoming overgrown with aggressive invasives. The goal of the Green City Partnerships is to remove these invasive plants, primarily through the work of dedicated volunteers, in order to re-establish that healthy native natural habitat. Join us for a restoration event by following the links on the right to your local Green City Partnership!

* thanks Elsa for help writing this post!

How did the weeds get here?

* This is the first of a monthly segment on frequently asked questions

Volunteers rolling up Ivy in Frink Park
Volunteers rolling up Ivy in Frink Park

Many flowering invasives such as Herb Robert and morning glory were planted by gardeners. Invasive knotweeds and English ivy were planted by landscapers for their ability to grow quickly and   create natural fencing barriers. Non-native blackberry was cultivated for its fruit, and plants like the St. Johnswort were introduced for their medicinal benefits.

Others such as Eurasian water milfoil were accidentally brought across the oceans in shipments or carried on ship ballasts.

While the invasive plants we remove at work parties have come to the Puget Sound region in different ways from different places, they all share an aggressive growth pattern that allows them to drive out the native plant communities that have existed here for centuries. To join in the effort to restore biodiversity and functioning of urban natural areas in Seattle, Tacoma, Redmond, Kirkland, and Kent, visit our partnership websites linked in the right sidebar of this blog. We hope to see you soon!