One of the things we love about Humboldt are the beautiful gardens, yards, and plant life! Humboldt is a habitat for many creatures, humans and animals alike.
The East Multnomah Soil and Water Conservation District is a fantastic resource in our very own neighborhood for information about planting native plants, identifying invasive plants, and reducing your water usage. Their location at 5211 N Williams Ave is entirely naturescaped with Portland native plants and is open to the public to explore. Take a walk around their property and see a great example of how naturescaping can work in a small urban lot. You can read more about the landscape, and their historic 1904 building, on their website here.
The Backyard Habitat Certification Program is a local program sponsored by the Columbia Land Trust and the Bird Alliance of Oregon. Program participants receive information about native plants, water usage, and invasive species, and a site visit from a trained volunteer to guide their habitat planting.
You don’t need to wait for your site visit to get started on creating your habitat – check out the facebook page Friends of Backyard Habitats to start learning from program participants and other habitat-friendly gardeners.
Invasive Species in Humboldt
Invasive species are plants not local to the Willamette Valley that spread easily in their introduced environment. They can overpower native plants, decreasing habitat and biodiversity for insects and creatures that can’t use them in the same way.
Two species that are prevalent in Humboldt are Tree-of-Heaven, ailanthus altissima, and foxtail. Check back for more updates about other invasive species like Himalayan blackberry, foxglove, Oregon flag iris, and more. In the meantime, you can read about Portland native plants and nuisance plants on the Portland Plant List.
Tree-of-Heaven
Tree-of-Heaven (ailanthus altissima) has spread rapidly across the United States and is on the Portland Noxious Weed list. It can grow in many conditions other trees cannot tolerate, including out of concrete, sidewalks, or freeway walls. It crowds out other plants, and emits an allelopathic chemical from its roots that degrades and kills nearby plants. Normal removal measures like pruning or cutting down actually increase the infestation, as the plant reacts to this stress by sending up hundreds of suckers from its roots, which can be as far as 50 feet away.
Tree-of-Heaven is prevalent in Portland and in our neighborhood. One concern is that this is the preferred host plant of the spotted lanternfly, a non-native insect, that is currently devastating trees crops on the east coast and in the midwest, slowly expanding westward. Reducing tree-of-heaven in our neighborhood is a way to prevent future spotted lanternfly damage in our region.
You can see the local spread of Tree-of-Heaven on inaturalist and even report your own sightings.
When removing tree-of-heaven, timing is everything. It’s best to wait until the late summer/early fall when the tree is no longer actively growing and is instead pulling energy from its leaves down into the roots. This is when you can use the tree’s biology to your advantage. Depending on the size of the tree, you can either cut the tree and paint the trunk with herbicide, cut holes in the trunk and squirt with herbicide, or a combination of both. Targeted application of an herbicide containing glyphosate or triclopyr is recommended for removing Tree-of-Heaven.
You can read more detailed instructions on removing Tree-of-Heaven on the Oregon State University extension website.
Foxtail and Cheatgrass
Foxtail is a new invasive species in Portland, appearing over the last decade. It is not yet on any official invasive or nuisance species lists. However, this plant can be very dangerous to dogs, pets, and humans. The seedheads are barb-shaped and can work their way into paws and skin, which can be very painful and even deadly to your pet.
Keep an eye out for foxtail on your property, especially along sidewalks where small creatures may encounter it. Manual removal before the grass goes to seed is best to prevent more seeds from entering the seedbank and sprouting in the future.
A “grassroots” group has sprung up in Portland to fight foxtail, the Foxtail eRADication Crue. Check out their posts on instagram about removing foxtail and spreading the word to homeowners and businesses about the dangers of this weedy grass.
Want to get involved in removing Tree-of-Heaven and Foxtail in the Humboldt neighborhood? We can apply for grants for tools and organize work parties. Email us at lynne@humboldtportland.org if you’d like to help.