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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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Sign up for No Ivy Day Oct. 27, 2018 - with you, we can stop the invasive plant takeover

It's true that one person can make a difference. But a whole lot of people working together can move mountains (of ivy) and restore a forest, and a park, and a wetland and more. ivy

Here's a great chance to team up in a citywide volunteer day to remove ivy and other invasive plants and help restore our natural areas and forests. You'll never look at our forests and natural areas the same way again.

Sign up for the15th annual citywide No Ivy Day, October 27, 2018 from 9 a.m. to noon

Choose the site that works best for you - from  Gateway Green and Nadaka Nature Park on the east side to Forest Park and Westlake Woodland on the west.

Led by our sister bureau, Portland Parks & Recreation, the events involve numerous community groups as partners. Refreshments, tools, and instruction will be provided at all locations.

Afterwards, you can join in a free celebration lunch and raffle from 12:30 p.m. to 1:30 p.m. at these locations: Mt Tabor, Forest Park and Marquam Nature Park. For more information sign up here.

Sign up now  - register for No Ivy Day October 27, 2018.

P.S. Want to see what else we're doing?

Citywide - Environmental Services restores natural areas and removes invasive plants throughout the year. Find out about invasive species management

Your garden - Environmental Services offers a poster of invasive plants and native plants and other resources. Find out about what to plant and what to pull.


Growing More Than Trees: Partnerships and Healthy Urban Watersheds

July 24, 2018

We know green infrastructure is about more than the plants. When we plant a tree to help manage stormwater, we’re introducing a new, long-lived resident into the landscape. A tree is shade on a playground, a restorative view from a classroom window, an air filter for the fallout of urban life. Our investments enhance the lives of Portlanders, and they’re only possible through partnerships with the community. Thanks to these community partnerships, our work – and celebration – of healthy watersheds and community has come to fruit in the Lents neighborhood.

Since 2011, the Environmental Services Tree Program has partnered with the Confluence Environmental Center to helps us better serve community through AmeriCorps service placements. Our AmeriCorps members provide opportunities for underserved Portlanders through education, leadership, and the chance to make tangible change in the landscape. Last winter, our AmeriCorps member (Max Rodrigues, pictured below, front row, right) teamed up with Rosemary Anderson High School students to plant trees at the Wattles Boys and Girls Club. Max and Friends of Trees staff spent time in the classroom with students teaching them about trees and the many benefits trees provide for people. Students helped choose the trees they wanted to see on their campus, and then spent an afternoon hands-on, planting their new trees in the school yard. The trees include our native Oregon white oak, evergreen interior live oak, and beautifully flowering cultivars of silverbell and dogwood. While students enjoy their summer break, we’ll be watering the trees for the next three summers to help get them going in their new homes.

These new school yard trees join street trees planted in front of the school and throughout the Lents neighborhood and the Jade District through other BES-community partnerships.

If you’re interested in a map of the school trees to test your tree identification skills, come find us at the Lents Fair on Sunday, August 5th, from 11am to 4pm. We’ll be at SE 92nd and SE Harold, near Wattles Boys and Girls Club and the Belmont goats. In addition to the trees, Environmental Services staff are also excited to share the latest information about our most recent commitment to Lents: The Lents Stabilization and Job Creation Collaborative.


Wattles campus is adjacent to busy transportation corridors. Trees help to provide clean air and visual barriers.

Students at work!


Planting crew poses for a post-planting photo.

A blooming Rosy Ridge silverbell, Halesia carolina ‘Rosy Ridge’

Greening the Jade District one tree at a time

It's Getting Hot! Don't Forget to Water Your Trees

July 11, 2018

Protect your investment in new trees: water them!

Summer is upon us in the Pacific Northwest, and that means it’s time to keep a careful eye on your newly planted trees (those that were planted in the last 3-5 years). The process of being transplanted is stressful, and your new tree doesn’t yet have the roots it needs to be self-sufficient.

So, how much should you water? There’s no hard-and-fast rule for watering trees. How much water the tree needs depends on the kind of tree it is, the soil it’s planted in, and the microclimate around it. Here are a few tips:

  • Start with about 10 gallons per week for every 1” of caliper (“caliper” is the width of your tree’s trunk, measured 6” above the soil line). So, if your new tree is 1.5” in diameter at its base, start with 15 gallons per week.
  • Water your tree deeply, so that the entire area where the roots are (the “root zone”) is moistened, not just the surface. A temporary berm (or raised barrier) at the tree’s dripline (the area directly under the outer circumference of the branches) helps to direct water to the roots while the tree is young. You can break this berm down after a few summers.
  • Mulch under and around the tree to help keep the soil moist and cool. Mulch should be 3-4” deep. Do not pile mulch against the trunk!  It’s a good idea to keep mulch around the tree for life.
  • Don’t overwater or underwater! Keep the soil moist like a wrung-out sponge. Before you water, take a hand tool and dig down a couple of inches. Is the soil still moist? No need to water. Is the soil bone-dry? Try increasing the amount of water slightly, add a berm to capture water, or add mulch to retain it (see above).
  • During those times when it is particularly hot and dry for an extended period, you might need to water the tree more than once a week.  If the leaves begin to wilt and the soil is dry, an extra watering day might be just what the tree needs.

watering a tree

All you need to water a tree is a bucket! Water your tree deeply so that the entire root zone is moistened, not just the surface.

Celebrating another year of tree planting!

July 2, 2018

The Environmental Services Tree Program (ESTP) welcomes 3,000+ new trees to the City

As we gear up for the next tree planting season, we pause for a breath and reflect on the planting season that just ended. That breath is all the sweeter thanks to Portland’s urban trees that help to clean the air, capture the rain, and give the birds perches to sing from. In this moment, we benefit from the trees planted by past generations. To do our part and ensure that future generations benefit from an urban tree canopy, we keep planting.

Planting and care of trees in the city is made possible by the coordination of many groups. Nurseries, landscape contractors, non-profits, city bureaus, private property owners, and a great diversity of passionate volunteers all play a role in the richness of the urban forest around us. Because of the hard work of all these people, we are pleased to report that more than 3,000 new trees were planted through ESTP programs during the 2017-2018 planting season. Thank you to all our partners who made this work possible!

New street trees on SE Holgate

A long line of new street trees graces SE Holgate Blvd at 82nd Ave. Broadleaf evergreens, such as these strawberry trees, provide clean air year-round.

Environmental Services Tree Program 2017-2018 Season Highlights

  • 2,436 street and yard trees planted at residential properties with our non-profit partner Friends of Trees.
  • 449 street trees at private residences, apartments, businesses, and non-profit properties, planted directly through ESTP with the help of our professional landscape contractors.
  • 165 yard trees approved for Treebate, a one-time rebate for single-family residents who buy and plant yard trees on their own.
  • 120 trees planted as part of special projects at schools, churches, and transportation corridors.
  • 5 new species of evergreen trees added to our street tree repertoire, including Baker cypress (Cupressus bakeri), bay laurel (Laurus nobilis), box-leaf azara (Azara microphylla), canyon live oak (Quercus chrysolepis), and strawberry tree (Arbutus unedo).

Now is the time to prepare for next planting season!

Are you interested in planting trees at a single-family residential property?

  • Contact Friends of Trees to learn how to get involved in your once-a-year neighborhood planting day.
  • Rather plant on your own? Treebate returns September 1.
  • Interested in removing and replacing a dead tree? Don’t wait until the last minute! Permitting, tree removal, and stump grinding all take time. Visit the Portland Trees website to learn more about tree removal permits.

Are you interested in planting street trees at an apartment, business, or non-profit property?

The Environmental Services Tree Program is taking sign-ups now! Call 503-823-2255, email, or visit the Environmental Services Tree Program website to learn more.

Alien Plant Invader: Blessed Milk Thistle

June 4, 2018

Blessed milk thistle presents something of a dilemma. On the one hand, it is grown for the herbal supplement market; on the other hand, it has escaped cultivation and is over-running parts of California. For the time being, milk thistle is uncommon in northwest Oregon. Let’s keep it that way! Early detection means that we have a chance of eliminating this alien plant invader from Portland. 

blessed milk thistle

Blessed milk thistle

Blessed milk thistle is a Required Eradication species in Portland. That means – if you see it, you are required to report it: Call Mitch Bixby with the Environmental Services' Early Detection/Rapid Response Program at 503-823-2989 or email

Where have we seen milk thistle? 

It has been sighted in several locations along the Columbia Slough and on Sauvie Island, and is relatively more common in Clark County, Washington. As with most invasive species, it is typical to first see patches along transportation routes like railways and roadways. Clark County, Washington, reports active management of several infestations, as does Clackamas County. To date, aggressive management appears to be substantially reducing known patches.

What’s the problem?

Milk thistle is known to form dense patches that originate in open, disturbed areas. Like other thistles, these plants have persistent root systems and produce large amounts of windblown seed, making management difficult. Milk thistle reduces plant diversity as other species are displaced. Invasions are of particular concern in forage lands, where milk thistle also poses a health hazard to livestock.

How can you identify milk thistle? 

Milk thistle can grow to be six feet tall with distinctive white stripes in the leaves. Milk thistle is also very spiny, more so than bull thistle, with flowers and seedheads ringed by exceptionally sharp spines. blessed milk thistle

Distinctive white stripes on the leaves can help distinguish blessed milk thistle from other thistle species.  blessed milk thistle

Sharp spines adorn the flowers and stems of the blessed milk thistle.

What can folks do about it?

Control where it goes

  • The best way to do this is to treat plants in the spring, before flowers form and increasing the risk for seeds to blow away.

Control where it grows

Dig: Cutting and digging is possible, but not especially effective on larger infestations. These are also particularly spiny plants, which discourage casual handling.

  • Treat: Low rates of herbicide appear to keep milk thistle under control.
  • Check: monitor the site at least annually, and especially years two and three after treatment, as any surviving seed takes its big opportunity to sprout!

If you suspect you’ve found milk thistle, the City of Portland requires you to report it.  Still, because of its prickly nature, you may decide to take advantage of the free management assistance available from the city.  You can report suspected patches to Mitch Bixby with the Environmental Services' Early Detection/Rapid Response Program at 503-823-2989 or