Resource Guide for Healthy Replacement Plants
Armenian (Himalayan) Blackberry (Rubus armeniacus)
Use a "top-down" approach, and start with trees. Take some cues from your neighborhood. Which trees are healthy and growing well? Consider any issues with the mature height and root spread, especially if you live in urban areas (call your City Planning Department). If you live in a rural area, use native species in natural areas. Armenian Blackberry and non-native blackberry vines in our region grow best in full to part sun. So, using shade from trees provides a measure of long-term control. Only plant as many trees as you can easily maintain the first two years. Add more as the blackberry cover is reduced. Here are some plant replacement options: Ponderosa Pine (N), Shore Pine (N), Douglas Fir (N), Incense Cedar (N), Western Hemlock (N), Kousa Dogwood, Tulip Tree, and Red Maple. [Note: (N) = Native to Western Oregon]
French Broom (Genista monspessulana)
For simplicity, we'll address all the noxious "brooms" (French, Scotch, Spanish & Portuguese) at once. Use the same "top-down" approach as used for Armenian Blackberry. Start with trees. Let's add a few riparian options: Western Red Cedar (N), White Alder (N), Oregon Myrtle (N), and Big Leaf Maple (N). Add some tall shrubs after trees begin to establish (approximately 3 years after planting). Here are some common shrubs to consider: Tall Oregon Grape (N), Vine Maple (N), Indian Plum (N), Western Hazel (N), Red Flowering Currant (N), Red Elderberry (Coastal) (N), Blue Elderberry (Inland) (N), and Nootka Rose (N).
Mole Plant & Other Spurge Species (Euphorbia lathyrus, E. characias, E. myrsinites)
Focus your efforts on controlling this plant, which is toxic to humans and livestock. Always wear gloves and long sleeves, and pull to remove plants when the soil is soft. As fewer plants remain, replant with herbaceous species of your choosing. Here are some options: Asiatic Lily, Lily of the Nile, Daylily, Douglas Iris (N), Toughleaf Iris (N), California Poppy (N), and Riverbank Lupine (N). Near pastures, use your choice of forage grasses and clover. In wild meadows, consider Western Yarrow (N) and native asters, like Narrowleaf Mule Ears (N), Oregon Sunshine (N), and Douglas Aster (N). You can help Monarch Butterflies by planting Narrowleaf Milkweed (N), Heartleaf Milkweed (N) (rocky soil), or Showy Milkweed (N).
Gorse (Ulex europaeus)
Found mainly on the coast, this formidable foe is dense, spiny and highly flammable. Use the fast-growing conditions to your advantage. While you focus on reducing gorse numbers, replant with robust, native species. In addition to the native trees and shrubs from above, here are a few more plants that should work well in the Coast Range: Twinberry (N), Evergreen Huckleberry (N), Swordfern (N), Red Osier Dogwood (N), Salmonberry (N), Thimbleberry (N), and Western Azalea (some spots) (N).
Milk Thistle (Silybum marianum)
Milk thistle is often found on sites with disturbed soil and is very common in pastures. Your replanting plans should be geared toward your goals and uses. In pastures, for example, seed any disturbed bare ground with forage grasses. Monitor and mow periodically to keep the thistle from bolting and going to seed. A single plant can produce thousands of seeds, so the key is preventing seed formation and spread. In other areas, try planting trees and tall shrubs. This will reduce the number and spread of this toxic plant. Refer to the plant lists above for replacement ideas.
Puncturevine / Caltrops (Tribulus terrestris)
Ah, puncturevine! If ever you've had the "privilege" of pulling its spiny seeds from bicycle tires, stroller wheels, flip-flops, seed spreaders, or Fido's paws, you won't soon forget it. This annual weed can produce hundreds of seeds from a single plant in a single season. Given its proclivity for gravel drives, sidewalk cracks, and compacted soil, you won't have many options for replacement plants. Instead, focus on prevention and control efforts: (1) Minimize disturbance of gravel and soil; (2) Remove scattered seed (use an old piece of carpet, yoga mat scrap, or sweep/vacuum up); (3) Cut the single taproot, before flowers go to seed, bag plants/seed, and take to the landfill. Begin watching for this weed in the Spring. It may continue to flower through early Fall
Scotch Broom (Cytisus scoparius)
Refer to French Broom above. Here are a few dry site shrubs to consider: California Hazel (N), Coyote Brush (N), and Blue Blossom (N).
Spurge Laurel (Daphne laureola)
Spurge Laurel is toxic to humans and domestic animals. Certain birds and rodents, however, consume the berries and deposit seeds in new locations. While Spurge Laurel can also spread via sprouting, the primary focus should be on limiting seed dispersal. Always wear gloves and avoid contact with skin while pulling or otherwise handling this plant. The sap can cause skin irritation and dermatitis. Although uncommon, respiratory irritation can occur from inhaled droplets. Bag-pulled plants and berries and dispose of them responsibly. Do not add them to your compost bin. Spurge Laurel thrives in shade, so tree planting is not the go-to control method. In your yard, plant shade-loving plants, like Fragrant Sweet Box, Japanese Painted Fern, Brunnera, Big Root Geranium, Bear's Breeches, and Rhododendrons. In forested areas, consider Creeping Oregon Grape (N), Deer Fern (N), Creeping Snowberry (N), and Pacific Bleeding Heart (N).
Tansy Ragwort (Senecio jacobaea)
Tansy Ragwort is a "primary succession, pioneer plant". It often germinates after soil disturbance activities, such as road grading, construction, grazing, or fire. This biennial plant is a notorious horse and cattle killer, so please monitor your property for toxic tansy - even if you don't own livestock. Plants will still go to seed if they are flowering when pulled. Therefore, remove and bag any flowering plants/heads and keep them out of compost bins. Always wear gloves when handling this weed. Fortunately, there are effective biocontrol insects at work in Douglas County. Consider leaving some green, vegetative tansy plants (away from livestock) to keep populations high for the Cinnabar Moth Larvae and Tansy Ragwort Flea Beetle. See the list above for Gopher/Mole Plant replacements. Here are some other wildflowers you may enjoy: Meadow Checkermallow (N), Cusick's Checkermallow (N), and Western Meadowrue (N). Don't plant these in/near pastures.
Yellow Star Thistle (Centaurea solstitialis)
Population densities are very high for this weed in Jackson and Josephine Counties. In Douglas County, numbers are high at low elevations, mostly south of Sutherlin. This annual weed prefers hot, dry summers and well-drained soils. Look for it in open, sunny areas, like roadsides and waste areas. The spines are a nuisance, but the bigger issue is the toxicity to horses. Horses that routinely graze these plants may starve or suffer dehydration from "chewing disease". Neurologic effects from consuming large quantities of Yellow Starthistle are irreversible. Put on your gloves before pulling plants. Bag and dispose of plants properly. Depending on the location, you may be able to keep plants from going to seed by using a mower or weed trimmer. Refer to the suggested replacement plants above for the Gopher/Mole Plant or Tansy Ragwort. You may also want to try Clarkia/Farewell to Spring (N), Globe Gilia (N), and Sulphur Buckwheat (N).
Bull Thistle (Cirsium vulgare)
This common thistle is found throughout Douglas County. It's a biennial, meaning it completes its lifecycle within two years. In the first year, a rosette forms with leaves radiating from a central taproot. In the second year, a vertical stem(s) forms to support flowers and seeds. Fortunately, this thistle spreads only by seed, unlike the Canada Thistle, making control measures easier. Mow or clip the stems to keep the plant from forming flowers, or use a sharp shovel to cut the taproot below the rosette. You can place the plants in your compost bin if no mature flowers or seeds have formed. Replant bare spots with suitable seeds or plants—Replant with sun-loving plants of your choosing. For a "mowable mix" in a low-maintenance lawn, add some Western Yarrow (N), California Poppy (N), Five Spot (N), Small Lupine (N), and Miniature Lupine (N).
Fuller's Teasel (Dipsacus fullonum)
Their distinctive seed heads quickly identify Teasel at the apex of tall stalks and terminal ends of side shoots. Fuller's Teasel can often be found in abundance within wetlands, wet meadows, pond edges, and along slow-moving streams. Like bull thistle, this plant is (most often) a biennial. The first year's rosette of leaves is flatted and appressed to the soil. In the second year, teasel plants bolt and form purple flowers, starting around June of each year. Since Teasel spreads by seed, clipping the stalks at the base when the plants are starting to flower should prevent seed set. If you miss this window of opportunity, you can still carefully remove the seed heads (using pruners) and place them in a trash bin. Hold the seed heads upright while doing this to prevent spilling on the ground. Consider replanting with the plants listed above for tansy ragwort. Add Common Sunflower (N), Black-eyed Susan (N), and your favorite Zinnias in flower bed borders. These flowers will attract goldfinches and provide alternatives to teasel seeds.