This noxious weed thrives in dry, sandy soils and is found community-wide on both private property and on commons.  Spotted knapweed rapidly invades disturbed areas (for example, in areas of recent construction), but is also capable of establishing in well‐managed landscapes. This weed reproduces exclusively by seed, which can be spread by wind, water, wildlife, and people – including by foot traffic and tire treads, so it is common to see Spotted knapweed along roads, bike paths, driveway edges, and paths to trash enclosures in Sunriver.

Spotted knapweed is a perennial that forms rosettes during the winter and early spring which grow into a multi-stemmed flowering plant in late spring and summer.  The plants live for 3-9 years and are usually 1-3 feet in height.  Spotted knapweed has the following, distinct characteristics:

• Root: A stout taproot makes Spotted knapweed relatively easy to pull.
• Leaves: The pale to medium greyish-green, deeply lobed leaves are wider and longer in the rosette and at the base of the plant, alternate on the stem, and become shorter and more linear at the top of the plant.
• Stem: Plants may have 1-20 stiff, upright, and branched stems that are covered with downy hairs.  Small plants may have a single stem with one flower head. Large plants may have multiple stems with multiple branches and over 100 flower heads.
• Flowers: Egg-shaped buds, resembling artichokes, are covered with scales (known as bracts) featuring dark, upside-down “V” markings at the tip, (giving them a “spotted” appearance). Delicate, stringy, pinkish-purple flowers are produced and the blooming flower resembles the shape of a pineapple.

Early detection, prevention, and persistence are the keys controlling Spotted knapweed. Survey your property early and often. Look for rosettes in April and May and for flowering plants in June, July, and August. Return to the same location throughout the season and the following spring and summer, as it can take several years to eliminate weeds where a seed bank has been established.

• Manual removal: The combination of Spotted knapweed’s stout taproot and the dry, loose soil typically found in Sunriver make pulling this weed an extremely effective method of control.  Gripping firmly at the base of the plant, give the plant a wiggle (or loosen the dirt in the immediate area with a narrow hand tool), and pull, removing as much of the taproot as possible.  Wear long sleeves and gloves when handling this plant, it can be a skin irritant to some people. Pulled plants must be bagged and disposed of in the trash to prevent spread.
• Chemical treatment: Selective application of broadleaf herbicides can be used to control Spotted knapweed in Sunriver, but effectiveness varies depending on the growth stage of the weed. Multiple treatments will be necessary to control late‐germinating plants and to kill new seedlings and plants unaffected by the initial treatment. Herbicides should only be applied at the rates and for the site conditions and/or land usage specified on the label of the product being used. Follow all label directions, the label is the law. Know your legal responsibility as a pesticide or herbicide applicator. 
• Mowing: Mowing will NOT control Spotted knapweed effectively. Plants are able to re‐sprout and flower again in the same season when mowed and can persist as short‐lived perennials or can flower below the level of the mower. Mowing plants that have produced flower heads or have gone to seed will exacerbate the spread of the weed.

Dalmatian toadflax grows well in Sunriver’s well-drained, sandy soil.  The weed is extremely drought tolerant and prefers sparsely vegetated sites – especially areas of recent disturbance (for example, construction).  Small, fairly isolated infestations of Dalmatian toadflax are more frequently seen in the south of the community, but the weed is present throughout Sunriver.  Spread of established plants can be rapid, usually via vegetative shoots that are produced from underground lateral rhizomes. New populations of Dalmatian toadflax can be established by seeds which can be spread by humans, animals (on fur, feet, and via the digestive system), vehicles, and sometimes water.

Dalmatian toadflax is a perennial with a narrow, upright shape (growing 2-3’ tall) that has multiple stems growing from a single woody base, thick water-conserving stems and leaves, and showy, yellow flowers that resemble snapdragons. Dalmatian toadflax has the following, distinct characteristics:

• Root: Dalmatian toadflax has an extensive root system that includes large taproots that can extend 4-10” below the soil surface and long creeping lateral roots that remain close to the surface and can extend 10’ from the parent plant. Vegetative buds formed along these lateral roots produce new plant shoots. Root fragments that are severed by hand pulling or tilling can generate new plants.
• Stem: Often appearing first as a single, upright, leafy stalk, Dalmatian toadflax will develop multiple upright stems (11-36” in height) from its stocky, woody base that appear more waxy and branch at the upper portion of the plant.
• Leaves:  Dalmatian toadflax has light blue-green, waxy-rubbery, pointed, heart-shaped leaves that are around 1” long.  Leaves are alternately and densely arranged around the stem, lack petioles (leave stems), and appear to clasp or “wrap” the stem.
• Flowers:  One-inch flowers are bright yellow with orange markings with elongated spurs similar to a snapdragon. Flowering occurs from mid-summer to early fall and flower buds, flowers, and seed pods are often present at the same time. Mature plants can produce up to 500,000 seeds and seeds remain viable in the soil for up to 10 years.

Early detection, prevention, and persistence are the keys controlling Dalmatian toadflax. Survey your property early and often. Look for the herbaceous stems in May and June and for flowering plants in June, July, and August.

• Manual removal:  Pulling Dalmatian toadflax is NOT effective as a control measure as it will sever thin lateral rhizomes, which will generate new roots and shoots, giving rise to new plants.  In other words, pulling makes the problem worse!  Grubbing out toadflax is effective only on newly established plants that have not developed an extensive root system. Cutting flower stalks to prevent seeding will temporarily prevent spread but plants will continue to re‐sprout throughout the growing season. Cut flower stalks must be bagged and disposed of in the trash to prevent spread.
• Chemical treatment: Selective application of broadleaf herbicides can significantly suppress or kill Dalmatian toadflax and should be used to control the weed in Sunriver. Due to the waxy nature of the plant a surfactant is recommended. Plants may be treated when they are actively growing or targeted in the fall when the plant is storing nutrients in its roots.  Multiple treatments may be necessary.  Herbicides should only be applied at the rates and for the site conditions and/or land usage specified on the label of the product being used. Follow all label directions, the label is the law. Know your legal responsibility as a pesticide or herbicide applicator or work with a certified applicator. 
• Mowing: Mowing will NOT control Dalmatian toadflax effectively. While it may diminish seed production if cut prior to flowering, mowing can increase sprouting from the weed’s extensive root system.

Bull thistle prefers sunny, open areas and can tolerate a wide range of conditions, from moist to dry soils, and is typically found in disturbed areas such as roadsides or where construction activity has taken place.  Small, fairly isolated infestations of bull thistle are present throughout Sunriver. 

As a biennial, bull thistle appears as large spiny-leafed rosette in its first year, and as a tall, branching plant with prickly leaves and purple flowers with swollen, spined bases, or bracts. Bull thistle has the following, distinct characteristics:

• Root: During the first year, bull thistle develops a rosette with a fleshy taproot which can be as long as 2’.
• Stem: Bull thistle bolts in its second year, forming a multi-branched stem that can grow 2-5’ tall. Stems of the plant are sparsely hairy, irregularly and spiny winged, green or brownish in color with purple veins.
• Leaves: The leaves have deep, pinnate lobes, and are hairy and prickly on top of the leaf and cottony below. Leaves are tipped with stout spines.
• Flowers: Purple flower heads, which appear July through September, are usually solitary on the end of each stem, gumdrop-shaped, with spines extending all around the 1½-2’ wide-base of the flower heads. 
• Seeds: Seeds are generally 1/16 inch long, oblong, somewhat flattened or curved, with a long, white, hairy plume. Seeds are dispersed by wind, water, animals, equipment, and people and may remain viable in the soil for 10 years. Bull thistle averages 100 seeds per flower head, but may produce up to 350 under ideal environmental conditions. A healthy plant may produce 5,000 to 50,000 seeds.

Although it is intimidating in appearance and can sometimes form large infestations, this thistle is not as challenging to control as many other noxious weeds.  Early detection, prevention, and persistence are the keys controlling bull thistle. Survey your property early and often. Look for rosettes of dark green, spiny leaves that are often covered in white hairs in the winter and spring and for flowering plants June-September.

• Manual removal: Bull thistle can be dug up with a shovel. A shovel or other tool can used to chop off leaves from one side of the plant to gain easier access to the roots, which can then be dug up. The best time to remove bull thistle is in the rosette stage by digging and removing the entire plant and taproot.  If the plant has bolted (produced stems), it is best to remove the plan prior to seeing any purple in the budding flower head by digging up the plant entirely or simply severing the root a couple of inches below the ground to remove the root crown.  Once the flowers have turned purple, they will go to seed even after being cut.  Bagging and disposing of flowering stems are critical to keep them from forming and spreading viable seed. 
• Chemical treatment: There are several herbicides that are effective on bull thistle.  Herbicides should be applied in late fall or early spring when bull thistles are in the seedling to rosette stage.
  After spraying, wait two weeks or more to give the herbicide time to work. Multiple treatments may be necessary.
  Herbicides should only be applied at the rates and for the site conditions and/or land usage specified on the label of the product being used. Follow all label directions, the label is the law. Know your legal responsibility as a pesticide or herbicide applicator or work with a certified applicator. 

Early detection is good for Scotch broom before it goes to seed and especially before the seeds are widely dispersed. Catching Scotch broom early in its life cycle is the best as typically in the first few years they don’t produce seeds.

• Manual Removal: Scotch broom can be dug up by hand when in its early years before its roots get stout but as it ages the roots get more stubborn and shovels or root pulling tools will be necessary to successfully pull it out. Cutting can temporarily stop seed growth but new shoots can grow from a cut taproot crown.
• Chemical Treatment: There are several herbicides that are effective on Scotch broom. Herbicides should be applied in late fall or early spring. After spraying wait two weeks or more to give the herbicide time to work. Multiple treatments may be necessary.  Herbicides should only be applied at the rates and for the site conditions and/or land usage specified on the label of the product being used. Follow all label directions, the label is the law. Know your legal responsibility as a pesticide or herbicide applicator or work with a certified applicator. Herbicides can be directly applied to cut stumps/crowns to prevent new sprouts if you cut the plants instead of pulling.
• Mowing:  Mowing is NOT an ideal method for Scotch broom control. While you can mow them down before seed pods are produced. The soil disturbance from the mowing can cause any seeds in the soil to germinate and sprout. The less soil disturbance the better.

Scotch broom is a green bushy deciduous shrub that grows three to six feet tall and flowers in spring/early summer.

• Roots A very deep taproot with shallower lateral roots make it harder to pull the older it gets plants can resprout from the taproot head if cut.
• Leaves oblong leaves are pointed at each end and grow in clusters of 3. The plant will lose its leaves during droughts but can continue to photosynthesize with its green stems.
• Stem the green stems have small ridges along them, when young, the stems are hairy, and they become less so as they mature.
• Flowers/Fruits Bright yellow flowers that resemble pea flowers bloom in the spring. The seed pods are dark brownish black pods that each contain about a dozen seeds. In mid-summer when the pods dry out, they explode open dispersing the seeds.

Scotch broom tends to like full sunlight in dry, sandy soils, but it can survive under a wide variety of soil conditions. However, it does not have high survivability in very arid or cold areas.

Canada thistle prefers moist soils and is typically found near waterways or in damp meadow areas in Sunriver. Canada thistle can also be found in disturbed areas such as roadsides or where construction activity has taken place. Canada thistle quickly establishes dense patches or “colonies”; a singular Canada thistle stem is a rare sight.

Canada thistle usually grows 2-4 feet tall with alternate, dark green, deeply lobed leaves that have spiny, toothed edges. Canada thistle has small (3/4 inch wide), compact flower heads that appear in clusters on the upper stems. Canada thistle has the following, distinct characteristics:

• Root: Canada thistle’s extensive root system includes taproot and rhizomes. The white roots run horizontally just beneath the surface of the soil and vertically 6-15’ deep. Root buds occur randomly along the roots and initiate new shoots whenever environmental conditions are favorable, primarily in the spring and fall.
• Stem: Canada thistle develops erect, branched, hairless or nearly hairless and ridged stems, 2-4’ tall.
• Leaves: The leaves are deeply lobed, hairy above and cottony below.
• Flowers: Small, rose-purple or lavender flower heads appear from June through October in clusters.  The urn-shaped base beneath the flower heads (or bracts) do not have spines. 
• Seeds: The smooth, light brown seeds are attached to a long, tan-colored hairy plume. Seeds are dispersed by wind, water, birds, animals, equipment, and people and may remain viable in the soil for 20 years.  Flowers produce from 40 to 80 seeds per head.

Canada thistle can be difficult to control because of its extensive root system. With mechanical and chemical methods available to manage Canada thistle, an integrated weed management plan may be most successful in controlling the invasive plant. 

• Mechanical control:  Canada thistle can be controlled by hand cutting or mowing BEFORE the plant sets seed. However, because of its extensive root system, hand cutting and mowing must be repeated at 3- to 4-week intervals until starch reserves in the roots are exhausted.  Given the perennial nature of this weed, hand removal is difficult and typically not very effective. Mowing will reduce plant height but does not usually eliminate flower or seed production completely. Mow when plants begin to bolt and repeat as necessary to prevent seed production. Mowing is not recommended as a single control method as plants often produce side branches with more flowers, even with repeated mowing and proper timing.  Poor timing of mowing can lead to disbursement of seeds, exacerbating the problem. Proper disposal of debris is essential in preventing spread. If flowers or seed are present, plants should be bagged and disposed of since seed will continue to mature within flower heads left onsite. 
• Chemical treatment: Canada thistle is best controlled with a selective post-emergent broadleaf herbicide. Herbicides should be applied in late fall or early spring when bull thistles are in the seedling to rosette stage. Spraying in fall before Canada thistle enters dormancy (before soil freezes up) usually gives the most consistent results. Spraying in spring in pre-bud to early bud growth stages can also be effective.
  Herbicides should only be applied at the rates and for the site conditions and/or land usage specified on the label of the product being used. Follow all label directions, the label is the law. Know your legal responsibility as a pesticide or herbicide applicator or work with a certified applicator. 

Russian thistle prefers loose or disturbed soil such as vacant lots, abandoned gardens, roadsides, and/or fence lines. Small, fairly isolated infestations of Russian thistle are present throughout Sunriver.

• Plant: Russian thistle is a bushy summer annual with numerous slender ascending stems that become fairly woody at maturity. Stem lengths vary from 8 to 36 inches and have a reddish/purplish stripes. The overall shape of the plant becomes oval to round.
• Root: Russian thistle has a taproot which can take root in under 12 hours with the correct soil conditions and temperatures.
• Stems: Stems vary from 8 to 36 inches in length and usually have reddish to purplish stripes.
• Flowers: The single, inconspicuous flowers lack petals and are borne above a pair of small spine-tipped bracts where the narrow leaves meet the stem.
• Seeds: Russian thistle seeds begin to germinate when it is exposed to the property temperature (52 to 90 degrees F) and moisture conditions. As it uncoils, the young taproot extends into the soil within about 12 hours, giving it a great advantage over other native plants. Russian thistle normally will not germinate successfully in firm soil, the soil in the sites must be loose. Seed viability is rapidly lost, over 90% of the seed wither germinate or decay in the soil in the first year. A large Russian thistle plant may produce more than 200,000 seeds.

It is best to control Russian thistle in its smallest stage as a young plant. In this stage the seedlings have very finely dissected leaves that almost look like pine needles. Leaves of young plants are fleshy, dark green, narrow, and about 1 inch in length.

• Manual removal: Early detection is key to controlling Russian thistle. Small populations of Russian thistle are easily pulled or hoed out at early growth stages. If plants have already stated producing seed, it is best to collect the plants and dispose of them to prevent new infestations.
• Chemical Treatment: Many herbicides are also effective against Russian thistle. Post emergent applications are very effective; however, the treatments must be made when plants are small. Reapplication of post emergent herbicides is often needed due to repeated dispersal of seed germination later in the season following rainfall. 
  Herbicides should only be applied at the rates and for the site conditions and/or land usage specified on the label of the product being used. Follow all label directions, the label is the law. Know your legal responsibility as a pesticide or herbicide applicator or work with a certified applicator.