Restoration Best Practices: Site Preparation Methods

Welcome to the first post in our new series about best practices in ecological restoration. Through this series we hope to provide an accessible but thorough outline of the most important elements of implementing ecological restoration projects. Nearly everything to do with ecological restoration is complex, and there is still a lot of research being done into best practices, so it is important to keep an eye open for new information. Our goal is to outline the basics, and point you in the direction of more detailed information if you choose to go in depth on any topics.

We are starting our ecological restoration best practices series with a focus on site preparation. The importance of site preparation is often underestimated but can have a huge impact on the success of your restoration project. If you would like to go more in depth into a range of site preparation issues, we highly recommend the Xerces Society “Organic Site Preparation for Wildflower Establishment” document.

Timing

Seeds:

The time of year that you choose to disperse native plant seeds at your restoration site is extremely important. Native plant seeding usually happens either in the fall or spring in the Pacific Northwest. In Southern Oregon, fall is generally the best time to get seeds in the ground, as it gives time for in-ground stratification (cold treatment) and mimics the seeding cycles of most native plants. Early spring can also be a hard time to do site preparation if the ground is too wet, or covered in snow! But spring seeding is still a good option if site preparation is possible and the seeds you are using don’t require a deep winter stratification.

Containerized Plants:

Planting potted native plants is generally best done in the fall to provide time for settling and root growth, but early spring is an option if the ground is not too frozen and supplemental water can be provided if spring rains are not sufficient.

Surveying Your Site

Recording the plants that already exist on your site is a great opportunity to better know the plants, their needs, and ways the native plants can be protected during the site preparation phase of your project. You can just write down a list in a notebook, or keep a spreadsheet where you can update information about shifts in flowering, seeding and other interesting observations you make. It’s also a really good idea to keep a record of any weeds you can identify and get to know their lifecycles, best times of year to work on removing them, and the best practices for how to reduce their impact on your restoration site.

Weed Removal

Inadequate weed suppression can have massive impacts on the success of your ecological restoration project. For most weeds, an important control method is removing or cutting back the plant before it goes to seed. Different weed plants tend to require a variety of removal methods, used in progression. Some of these methods include solarization and sheet mulching, mowing, flame weeding or burning, and selective and careful herbicide (incl. organic) use. To dive further into best practices for removing some of our most detrimental weeds in Southern Oregon, check out these documents:

Solarization and sheet mulching: these methods are best used for smaller sites without steep slopes. Solarization utilizes large sheets of clear UV-stable plastic to cover an area containing weeds for 2-6 months in warmer climates, and up to 6 months in colder climates. Many trials have shown solarization to be an extremely successful method of weed removal, as the heat that builds up under the plastic not only kills plants, but also any weed seed bank that has built up in the soil. Occultation is a variation on solarization, where thick black plastic tarps are used to cut of access to sunlight, and produce large amounts of heat. Sheet mulching is useful in areas that are too shady for solarization to be effective, or in areas where laying out a large piece of plastic is impractical due to landscape features. Sheet mulching involves layering nitrogen and carbon based materials to smother weeds and stop the seed bank from being able to germinate. For example, a layer of nitrogen-based material (eg. animal or plant composted materials, pellets, meals, grass clippings) is then topped with a layer of carbon-based material (eg. cardboard, paper, sawdust, woodbark), and then these layers are repeated 1-2 more times, making sure that a heavier carbon-based material is on top to hold everything down. 

Occultation with silage tarps at Jackson County OSU Extension

Mowing: this can be a very useful tool in ensuring a weed population doesn’t get to produce seed. For most weeds, using a mower or weed wacker to remove any seed heads before they -are pollinated is a fast and efficient way to deplete the plant’s ability to reproduce. That said, it can be hard to time mowing so that the plant doesn’t have the time and energy to enter into the flowering stage again, while also navigating any fire season restrictions on cutting dry grass. This method involves getting to know your weeds and their reproductive cycle well, and should be used in tandem with other weed control methods.

Hand-held flame weeder

Fire: flame weeders are an excellent resource for spring-time weed control. They must be used with great caution and attendance to fire restrictions, but they are an efficient and targeted method for removing weeds without impacting surrounding native plants. If you have a large area that would benefit from prescribed fire, get in touch with your local prescribed fire practitioners to see if there are any opportunities available for this work to be done on your land by trained professionals. In Southern Oregon, The Klamath Siskiyou Oak Network may be able to point you toward prescribed fire resources.

Smother cover crops: in areas where weed pressure is low to moderate, cover crops can be used to smother weed plants. Smother cover crops can also improve soil health and provide temporary forage for wildlife, including pollinators. This technique is best used on farmland or pasture that has access to irrigation and farming equipment. Certain varieties of buckwheat, sorghum, millet, oats, rye and vetch can be planted. Depending on the cover crop planted, they can not only compete aggressively with weeds for space, but also alter the nutrients in the soil and release allelopathic substances into the soil to make it undesirable for weed germination and growth. Timing and duration of the cover crop also varies depending upon species, but is very important to ensure that weed suppression is maximized.  

Herbicides: using synthetic herbicides to control weeds is a very contentious issue, but best practices generally determine that they should be used as a last resort, and in a very targeted and well-planned manner. This is particularly important in riparian zones where herbicides can make their way into the aquatic ecosystem. Herbicides alone are rarely able to control the most problematic weeds, and should be considered part of a regime that involves other weed control methods. There are some organic herbicides available to use, and successful use depends on targeted plant species. For more information it is worth checking out the “Roadside Habitat for Monarchs: Monarch Butterflies, Weeds and Herbicides” and “Organic Pesticides: Minimizing Risks to Pollinators and Beneficial Insects” documents produced by the Xerces Society.

Ground Disturbance

If you are utilizing native seeds in your restoration project, gentle ground disturbance is a useful step to take just before you are set to distribute the seed. It helps the seed penetrate the soil more rapidly and protect it from being washed elsewhere by rain, and from browsing wildlife (birds love seed!).

Site preparation: raking in the Ashland watershed

Raking: this is a great method for restoration projects in woodlands, forest floors, sloped locations and small areas being seeded. Hand raking disturbs the ground enough to allow seed to get into the soil, but doesn’t disturb soil structure or existing native plants as much as more intensive ground disturbance. It also allows you to easily avoid any preexisting native plants that you are trying to protect.

Light tillage: you can also use a small tiller / cultivator to prepare an area for seeding. This is particularly useful in pasture and farmland. If you have a weed issues, this is a method that should be considered carefully, as ground disturbance can expose weed seed banks in the soil to the ideal conditions for growth.

Keep an eye out for our next blog post about best practices in native plant seeding for your ecological restoration project! Don’t forget that we are always updating the Rogue Native Plant Partnership Resources Library with new useful resources for ecological restoration projects – from backyards to woodlands and everything in between!

More Useful Site Preparation Resources

November Native Plant of the Month: Rubber Rabbitbrush

11/12/19 – RNPP has started writing a new Native Plant of the Month column for the Rogue Basin Partnership newsletter! You can find the full RBP October newsletter here, and our Native Plant of the Month Column copied below.

Native Plant of the Month: Rubber Rabbitbrush

Rubber Rabbitbrush (Ericameria nauseosa) is a small perennial shrub that grows in a wide variety of harsh habitats from the west coast all the way to Texas and North Dakota. In the Southern Cascades you can still see the last of its flowers in November, but its prime flowering season is August-October. It’s bright and prolific yellow flowers are a very abundant source of food for pollinating insects and birds, and the leaves are an important winter food for browsing mammals.

Rubber Rabbitbrush is an excellent revegetation plant in disturbed areas, as it propagates easily and grows fast in a range of poor soil conditions. It also thrives in dry environments, making it a great choice for xeriscaping (landscapes designed to reduce or eliminate the need for irrigation). It is often found growing in desert-like habitats alongside sagebrush – both of which are in the Asteraceae (sunflower) family. Its deep growing roots also make it very useful for stabilizing ground prone to erosion or damaged by mining.

Ethnobotanical uses of the plant include making a yellow dye from the flowers, using the rubbery stems in basket making, and making tea and chewing gum. As its name suggests, it can actually be used to make rubber from the plant’s sap. Rubber production potential varies depending on the growing conditions, but it is known to produce more rubbery sap in dryer, hotter conditions.

Taxonomy fact: the “nauseosa” species name relates to the pungent smell the plant gives off when the leaves are rubbed. Some say it’s a pineapple-like aroma, while it’s more foul and rubbery to others.

 

October Native Plant of the Month: Vinegarweed

(10/11/19) – RNPP has started writing a new Native Plant of the Month column for the Rogue Basin Partnership newsletter! You can find the full RBP October newsletter here, and our Native Plant of the Month Column copied below.

Native Plant of the Month: Vinegarweed

While walking through open grassy woodlands and prairies during late summer, you may have encountered a strong smell of minty vinegar on the breeze, and maybe even heard the hum of insects that eagerly congregate on the annual herb commonly known as Vinegarweed. The attractive purple flowers are an important late summer pollen source for many insects, with flowers known to bloom into October.

This sun-loving herb is quite shade intolerant, and prefers dry soils below 2,200 ft between Washington and Baja California. It is known to have phytotoxic properties that prevent other plants from growing happily around it. This could make it an excellent plant for competing with invasive herbs. It is also unlikely to be palatable to browsing animals due to its highly fragrant oils. Seeds mature and can be collected in late fall, and sown directly (raked into soil) in fall or early spring.

Vinegarweed is known to be highly medicinal, and has been used by west coast tribes for many healing purposes, including for treatment of colds, throat inflammation, headaches, infected sores and aching teeth.

The species name Lanceolatum means “lance-shaped”, which relates to the shape of Vinegarweed’s leaves. It’s always nice when the scientific name relates to the plant’s appearance! Its lovely little purple flowers are also a great way to identify the plant, but the easiest way to identify Vinegarweed by far is its powerful fragrance – you can’t miss it!

USDA Plant Guide: https://plants.usda.gov/plantguide/pdf/cs_trla4.pdf

Upper Table Rock Seed Blitz and Yellow Starthistle Pulls

June 2017 – June 2019

For the third year in a row, volunteers with The Nature Conservancy and the Rogue Native Plant Partnership gathered on the slopes of Upper Table Rock to collect wildflower seed for future restoration projects and hand pull the highly invasive yellow starthistle.

This slideshow requires JavaScript.

Yellow starthistle (Centaurea solstitialis) is an exotic annual herbaceous plant in the knapweed genus. The seeds from this plant can germinate whenever there is enough moisture in the soil. It starts as a small bluish green rosette and grows slowly through the winter months. Once the heat of the summer comes this plant bolts to produce yellow flowers subtended by thorny spikes.

Although yellow starthistle is an annual species that dies every year, it is able to produce a long taproot that depletes the soil of moisture making it nearly impossible for native species to grow nearby. This species is particularly difficult to manage because it can continue to produce flowers and seeds even after continual mowing or grazing by producing flowers very low to the ground. At Upper Table Rocks, years of volunteer-based hand-pulling has resulted in the almost complete eradication of this plant from the wildflower meadows at the site!

Ecological restoration involves many steps. The first step is often to change the disturbance patterns at the site (in this case stop the yellow starthistle invasion) followed by seeding the site with native wildflower and grass seeds. These precious seeds are hard to come by and expensive in Southern Oregon. To help tackle these challenges, volunteers with The Rogue Native Plant Partnership help to collect wildflower and grass seeds from native plants nearby. Once enough seed has been collected, it will either be used directly on the site or grown out at a nearby farm (increased) if more seed is needed than can reasonably be collected from wild plants.

AUTHOR:

Kathryn Prive
Rogue Native Plant Partnership

 

Return to Blog Main Page

Restoring huckleberry habitat as a cultural resource

On September 26th a large group of volunteers including Cow Creek Band of Umpqua Tribe of Indians members, Forest Service and BLM employees and Rogue Native Plant Partnership volunteers converged on a recently burnt area just outside the town of Prospect in the High Cascades to help replant 1500 mountain huckleberry (Vaccinium membranaceum) plants.

This slideshow requires JavaScript.

The area was burned during the 2017 Broken Lookout fire. The well-established plants were grown by the Forest Service’s nursery in Dorena from seed fortuitously collected onsite only two weeks before the Broken Lookout Fire started. This project is a collaboration between the Forest Service, the Cow Creek Band of Umpqua Tribe of Indians and the Rogue Native Plant Partnership to restore an important cultural food resource.

It was a brisk but beautiful day up in the mountains, and after a smudging ceremony led by members of the Cow Creek Tribe, everyone got their planting equipment ready and hiked into the burn area to get huckleberries into the ground. In addition, monitoring plots were surveyed as part of a multi-year effort to obtain data that will help develop an understanding of the success of the replanting efforts.  There are still 8000 more plants to go in the ground, with that work being completed by contractors at the time of writing.

Huckleberries continue to be an incredibly important cultural food resource for Native Americans, and so many community members and government agencies coming together to support the replanting efforts is a powerful acknowledgement of understanding the huckleberry’s cultural significance. Thank you to everyone who came out for this great replanting effort!

AUTHOR:

Lilia Letsch
Rogue Native Plant Partnership

 

Return to Blog Main Page

Collecting milkweed seedpods for local pollinators and landowners

Ten Rogue Valley community members come together at the Forest Service’s J. Herbert Stone Nursery in Central Point to volunteer for a milkweed seedpod collecting event on September 9th. Even with a decent breeze sending the seed fluff (known more officially as “coma”) flying everywhere, we still managed to collect large amounts of both narrowleaf milkweed (Asclepias fascicularis) and showy milkweed (Asclepias speciosa) seed pods. The beds of narrowleaf and showy milkweed have been funded by the US Fish & Wildlife Service (USFWS), and the seeds will be used in special seed mixes being prepared for landowners to enhance pollinator habitat on private lands in the region.

This slideshow requires JavaScript.

Milkweed is a fantastic perennial flowering herb that is much loved by many pollinators, including the at-risk Monarch butterfly. Not too long-ago milkweed was an incredibly widespread plant, but has been eradicated in many areas in favor of agricultural crops, and now faces a lot of competition from introduced invasive plants. Luckily it is an easy plant to grow, and efforts are being put into introducing it back into the landscape on a broader scale. It couldn’t happen soon enough for the Monarch!

Many thanks to all of the volunteers who came out to help collect milkweed seeds and contribute to important pollinator habitat restoration!

Interesting taxonomy fact: In 1753, Swedish Botanist Carl Linnaeus named the genus Asclepias after Asclepius, the Greek god of healing.

AUTHOR:

Lilia Letsch
Rogue Native Plant Partnership

 

Return to Blog Main Page

Restoring disturbed ground on Mt Ashland with native forbs

June 2nd, 2019

We had a fantastic day on Mt Ashland on June 1st, working with a group of volunteers to plant out 4,500 native plant plugs in an area next to the Mt Ashland lodge that was recently disturbed by heavy machinery. Thanks to the folks at the Mt Ashland Ski Lodge for helping organize volunteers and providing snacks and drinks for everyone!

This slideshow requires JavaScript.

The plants were grown by Silver Springs Nursery in the Applegate, from seed that we collected in 2018 on Mt Ashland. The species that were planted out included Oregon Sunshine (Eriophyllum lanatum), Coyote Mint (Monardella sheltonii), Yarrow (Achillea millefolium), Roemer’s Fescue (Festuca roemeri), Squirretail grass (Elymus elymoides) and Sulphur Buckwheat (Eriogonum umbellatum). Once grown in, these plants will create a beautiful meadow of wildflowers and native bunch grasses, and great habitat for pollinators and birds!

Post-planting care will involve regular watering for the first year, and ensuring that the area is cordoned off from the public so that the small plants won’t be damaged under foot. We look forward to monitoring the survival rate and growth of these plants, and enjoying the first flush of wildflowers next spring.

Thanks to the amazing volunteers!

AUTHOR:

Lilia Letsch
Rogue Native Plant Partnership

 

Return to Blog Main Page

Growing plants for seed production at Long Shadow Fields

April 25, 2019

Long Shadow Fields in Talent is one of a handful of local farms working with the Rogue Native Plant Partnership to develop a new model of native forb seed production. Seed for native forbs – herbs, and grasses – can often be hard to come by in the amounts required for local ecological restoration projects. Growing such plants out for seeds is often cost prohibitive due to the amount of time it can take for plants to develop to the flowering stage, and the amount of labor required to harvest the seed. But through a non-profit / small farm partnership, we are hoping to alleviate the risks and pressures of growing native seed for restoration projects in the Rogue Basin.

This slideshow requires JavaScript.

Gary Kliewer at Long Shadow Fields grew a selection of native herbs and forbs from seeds that RNPP supplied from our wild seed harvesting events. A volunteer planting event was organized to help get a lot of the small native herbs in the ground. RNPP will continue to support Gary’s native seed production through volunteer labor, funding through grants, and technical support from a network of other experts in the Pacific Northwest.

The volunteer planting event on April 24th was a great success, we planted hundreds of native plugs and did some great networking and knowledge sharing. Thank you so much to everyone that came and helped! Keep an eye open for future events at Long Shadow Fields and other local farmers we are working with to grow regionally adapted native herbs and grasses for ecological restoration projects happening in our community.

Planting Wyethia into straight rows for ease of mechanical weeding.

AUTHOR:

Lilia Letsch
Rogue Native Plant Partnership

 

Return to Blog Main Page