Ecoroof in the Garden


Garden shed ecoroof

Last summer, my husband wanted to build a “garden shed” to replace the tiny dry-rotted structure we had in the driveway. I was thrilled about having a place to store garden tools and bikes, but struggled with the idea of having more impervious surface on our property. TJ agreed and decided to build an ecoroof on top of the shed to collect the storm water runoff.

The ecoroof captures rainfall and the overflow is directed down the sloped roof to a gutter, which flows into a 500-gallon water tank. There is a hose connected at the bottom of the tank so we can water the garden or use in case of emergency. The average annual rainfall in Portland, Oregon is about 40 inches. That is a lot of water that could be used on plants instead of going into the city’s storm drains.

TJ consulted the City of Portland’s Ecoroof Program web site for more information on design details. He had to construct the shed to withstand the weight of the soil and plants on the roof. TJ laid down a pervious membrane, hung the gutters and directed the flow into the water tank. Along three places on the roof, we placed some flat rocks above the gutter to slow down the rainfall and minimize erosion during heavy rains.

Following construction in October 2013, I climbed onto the roof with my shovel and a cup of coffee. It was time to plant!  Although I had never designed an ecoroof, I knew I wanted a mix of grasses, sedums, and spring bulbs. Below is the plant list I came up with:

Sedum Silver Moon, Red Ice SedumSisyrinchium Quaint and Queer, Armeria juniperifolia, October plant Sedum siebodii, Sedum “button”, Cape blanco – Sedum spathulifolium, black mondo grass, Echeveria secunda, Hens & chicks Sempervivum rojin, Double alpine geranium Erodium reichardii “Flore pleno”), Sedum reflexum “blue spruce,” blue oat grass, Mexican feather grass, Iris bulbs

phone 780

Michele laying out the plants on the ecoroof

Another feature on the roof is a metal bowl filled with stones and water which serves as a “bug bath” for bees and other insects. Last year, the bug bath was in the garden and was visited by tons of bees. I also put a small piece of driftwood on the roof for insects to use as habitat.

This summer, I plan to track all the critters I observe using the ecoroof to evaluate its habitat value. While our house sits on a busy city street, I see my urban lot as an important corridor for bees, insects and wildlife. The ecoroof serves as another spot in the yard for creatures to use.

TJ sold me on the idea of a garden shed and he built it using old cedar and vintage windows he salvaged from one of his construction projects. It was well on its way to being a beautiful, eco-friendly structure until he left the lawnmower in the yard, hung up our bikes and shoved my garden tools onto a small shelf so high I can barely reach them and moved in his tools and two motorcycles. As evidence in the photo below, our “eco-friendly”garden shed is really a motorcycle repair shop.  Sometimes in marriage, you just have to compromise, but I still have my planted roof and I love it.


Why Use Native Plants?

For many years, I worked as a wetland biologist at an ecological firm and spent a lot of time in the field observing native plants and the wildlife that rely on these ecosystems. I saw the devastating effects of invasive plants, some of which had escaped from residential gardens. It is important to understand that not all plants support wildlife equally.

Native plants support native birds, insects and wildlife. When invasive plants take over our gardens, natural areas, and parks, they decrease biodiversity and threaten habitats. Invasive vines twist themselves around trees and overtake the canopy ultimately killing trees that provide storm water benefits, shade, habitat and minimize erosion.

When I was home in the city, I saw urban gardens full of non-native and invasive plants. I wondered, why aren’t more people growing native plants and edibles in their gardens? I saw a lot of potential for these urban garden spaces to be filled with native plants, pollinators, and wildlife. That is what compelled me to put my plant knowledge to good use and start Purple Garden, a garden design business.

Native plants are also adapted to the climate they evolved in, which makes them less likely to require irrigation. Some of my favorite easy to grow Northwest natives include: Douglas hawthorn, blue blossom, vine maple, mock orange, highbush cranberry, Indian plum, salal, vine maple, evergreen huckleberry, red flowering current, black twinberry, snowberry, evergreen huckleberry, Oregon grape, alumroot, Cardwell’s penstemmon, piggy-back plant, wild ginger, white yarrow, deer fern, checker mallow, sword fern, and trillium.

To learn more about native plants, check local web sites for information on native plant sales in your area. You can typically buy plants for much less than retail prices. In the Portland Metro area, contact the East Multnomah Soil and Water Conservation District, Backyard Habitat Program for information on their spring/fall native plant sales.

Stinging Nettles

FH050005March is Stinging Nettle Harvest Time

So why isn’t everyone growing stinging nettles? Maybe because they deliver an unpleasant sting when they come into contact with your skin. These plants have tiny little hairs on them that contain formic acid. This is the same chemical those pesky red fire ants that roam around the sands of the southeastern United States contain.

Nettles do not sting when they are cooked, steeped in teas, or dried. Nettles are rich in iron, calcium, Vitamin C, potassium, magnesium, manganese, zinc, chromium, flavonoids, histamine, and serotonin. These plants help to alleviate the symptoms of seasonal allergies. Since I have been drinking nettle tea for the past 9 years, I have been able to eliminate the need for allergy medication. The only side effect of consuming nettles is a mild diuretic effect, so don’t drink right before bed.

You can make nettle tea, nettle spinach pie, or saute them in a little olive oil and tamari sauce. This plant is not only beautiful in the garden, but the birds love to eat the seeds they produce in the late spring.

If you decide to harvest stinging nettles, you must do so before they begin to flower, which is typically in late spring. Once the plants flower, their chemistry changes and they form calcium concretions, which can be harmful to the urinary tract. Don’t forget to take a pair of gloves.

Painting by Amy Ponteri

Painting by Amy Ponteri

Winter in the Garden

It rarely snows in Portland. When it does, the city goes into hibernation, which is good because it keeps people off the roads. It is beautiful to see snow in the landscape. Snow on trees and shrubs really highlight a plant’s form and structure. This Northwest Oregon grape looks beautiful covered in snow.

Oregon grape is one of my favorite Northwest natives. It is hardy, drought tolerant and looks great in the garden year-round. It is one of the first native shrubs to flower, which is a favorite food of hummingbirds.


My main focus in the garden in winter is providing food for birds. I always hang a bird feeder, which is frequented by black-capped chickadees. Today, I saw an Anna’s hummingbird in the garden. I think he was trying to figure out why the sugar water in the hummingbird feeder was frozen. Poor thing, he will have a wait until it thaws.


Hummingbird photo taken by Craig Tumer