TERRESTRIAL INVASIVE WEEDS OF THE LAKE TAHOE BASIN
A Comparison Guide to Non-native Invasive Weeds & Common Look-alikes TERRESTRIAL INVASIVE WEEDS OF THE LAKE TAHOE BASIN A Comparison Guide to Non-native Invasive Weeds & Common Look-alikes
Graphic Design Annaliese Miller
Illustrations © Annaliese Miller
Photography courtesy of: Jim Belsher-Howe, Robin Breckenridge, Beth Brenneman, Michael Charters, Joe DiTomaso, Susan Donaldson, Laura Ann Eliassen, Tim Hanson, Japhia Huhndorf, Ed King, Steve Matson, Annaliese Miller, Keir Morse, Susi Urie, Kathy VanZuuk, Charles Webber, Kathy Welch, Melanie Williams
Text The Lake Tahoe Basin Weed Coordinating Group
This manual is based upon the 2009 University of Nevada Publication Special Publication (SP-09-06), Invasive Weeds of the Lake Tahoe Basin (available at: https://www.unce.unr.edu/publications/files/nr/2009/sp0906.pdf). The Lake Tahoe Basin Weed Coordinating Group has reprinted the original University of Nevada Cooperative Extension publication in its current form with permission from the University of Nevada Cooperative Extension. The Lake Tahoe Basin Weed Coordinating Group assumes responsibility for the accuracy of all material not included in the original University of Nevada Cooperative Extension publication.
1 WHAT ARE NON-NATIVE INVASIVE WEEDS HOW TO USE THE GUIDEBOOK
For the purpose of this booklet, a non-native invasive The guidebook will help you identify non-native invasive weed is a plant growing outside of its natural range weeds threatening the Lake Tahoe Basin. Common and threatening native species diversity. In this book “look-alikes” are also included to help you differentiate we use the term weed and non-native invasive weed between desirable native plants and invasive weeds. interchangeably. Not all non-native plants are invasive. Each plant profile includes management information. Weeds readily establish in desired vegetation and Some invasive weeds may be controlled effectively by spread in a variety of settings, especially where lands homeowners, while other require professional assistance. have been disturbed. Look for these face icons at the top of the page: When weeds displace desired native plants they: = Non-native invasive weeds Report (pg. 87) • Disrupt wildlife habitat = Desirable look-alikes (native and non-invasive) • Reduce hunting and fishing potential • Change habitat aesthetics = Plants that could potentially become invasive. • Inhibit recreational activities and tourism (You may choose to avoid planting species that • Crowd out endangered species may become invasive on your property.) • Reduce forage value California and Nevada designate particularly troublesome • Increase soil erosion non-native invasive weeds as noxious weeds. Both states • Threaten lake clarity use a rating system based on distribution and relative tenacity to assist in prioritizing noxious weed control and eradication For example, in the Lake Tahoe Basin, weeds that have efforts. The ratings below are provided for each species. coarse or shallow root systems, such as perennial pepperweed and Dalmatian toadflax, increase soil erosion “A” rated: found in limited distribution throughout and threaten lake clarity. the state and considered top priority for eradication and control before they become widespread. Due to the severity of these impacts, California and Nevada “B” rated: may be established in scattered populations have designated many of the weeds featured in this book in the state; treatment priority is determined on a case- as noxious under state law, requiring actions to prevent by-case basis depending on the value of resources being the introduction, establishment and spread of these compromised, local distribution and available resources. detrimental pests. “C” rated: generally established and widespread. If you find a non-native invasive weed, please report Relative abundance of each species is also provided. the infestation to the appropriate county (see contact Widespread: Found at numerous locations in the Lake numbers on the inside back cover) or go online to Tahoe Basin. tahoeinvasiveweeds.org and complete the reporting form. Moderate: Found at several locations; large populations may occur at a few locations. Infrequent: Only at one or a few locations; no large populations. 2 3 PREVENTING THE SPREAD OF WEEDS WEED MAPPING
Prevention is the least expensive and most effective way The Lake Tahoe Basin Weed Coordinating Group has to halt the spread of non-native invasive weeds. been mapping weeds in the basin since 2002. Regular mapping and inventory helps us determine which species This requires: are present in the basin and implement appropriate • Educating workers and the public about the management actions. We also track patterns of spread importance of managing weeds on an ongoing basis and plan preventive practices. • Properly identifying weed species • Avoiding or treating existing weed populations We welcome your mapping information. Go to • Preventing weed seeds or other plant parts from tahoeinvasiveweeds.org and complete the reporting establishing new or bigger populations form. You’ll also find additional photos and information about invasive weeds, plus maps showing locations of Steps you can take: known infestations in the Lake Tahoe area. 1. Use this book to identify invasive weeds in your area. 2. Inspect your work or play area. Identify any invasive weeds; When collecting data, please include: map the location of the weeds. • Date surveyed 3. Clean vehicles, shovels and other soil-disturbing equipment • Weed name (preferably the scientific name) prior to entering a site to avoid introducing weeds. • Latitude and longitude of the observation if available 4. Don’t introduce weed-contaminated soil, fill, or other • Thorough description of the location materials to new sites. Use certified weed-free products. • Number of plants 5. Check shoes, clothing, bicycles and vehicles regularly • Pictures if possible for weed seeds or other plant parts. Carefully remove Please do not take any management actions or remove and dispose of weedy materials. plants until they have been positively identified. Consult 6. Pressure-wash vehicles and equipment after driving your county weed contact for assistance. See page 87. in weedy areas. Periodically monitor and treat areas to prevent weedy plants from establishing. Free invasive weed mapping Apps available: 7. Establish a decontamination area such as a tarp for • Calflora Observer Pro – calflora.org cleaning clothing and equipment. • EDDMapS West – eddmaps.org/west 8. Don’t walk, ride or drive through infestations. When operating vehicles, stay on established roads or trails. 9. If dogs accompany you, check their paws and coats for weed seeds and other plant parts and remove them. 10. Don’t plant weeds in your garden or landscape. 11. Get advice for treatment on private property from your local county agriculture department or weed district. tahoeinvasiveweeds.org (See contact information on back page.) 4 5 INDEX COMMON NAME Scientific Name CODE Page INDEX COMMON NAME Scientific Name CODE Page THISTLES AND LOOK-ALIKES TOADFLAX AND LOOK-ALIKES L Invasive L Invasive BULL THISTLE Cirsium vulgare CIVU 12-13 DALMATIAN TOADFLAX Linaria dalmatica LIDA 50-51 CANADA THISTLE Cirsium arvense CIAR4 14-15 YELLOW TOADFLAX Linaria vulgaris LIVU2 52-53 MUSK THISTLE Carduus nutans CANU4 16-17 J Look-alike SCOTCH THISTLE Onopordum acanthium ONAC 18-19 SNAP DRAGON Antirrhinum majus ANMA3 54-55 J Look-alike DAISIES AND LOOK-ALIKES ANDERSON’S THISTLE Cirsium andersonii CIAN 20-21 Invasive ELK THISTLE Cirsium scariosum CISC2 22-23 L OXEYE DAISY Leucanthemum vulgare LEVU 56-57 KNAPWEEDS AND LOOK-ALIKES J Look-alike L Invasive SHASTA DAISY Leucanthemum maximum LEMA8 58-59 DIFFUSE KNAPWEED Centaurea diffusa CEDI3 24-25 BROOMS RUSSIAN KNAPWEED Acroptilon repens ACRE 26-27 Invasive SPOTTED KNAPWEED Centaurea stoebe CEST8 28-29 L SCOTCH BROOM Cytisus scoparius CYSC4 60-61 Look-alike J SPANISH BROOM Spartium junceum SPJU2 62-63 AMERICAN- ASTER Symphyotrichum spp. 30-31 K Look-alike GRASSES AND LOOK-ALIKES BACHELOR’S BUTTONS Centaurea cyanus CECY2 32-33 L Invasive BARBED GOATGRASS Aegilops triuncialis AETR 64-65 YELLOW ASTERS AND LOOK-ALIKES JOINTED GOATGRASS Aegilops cylindrica AECY 66-67 L Invasive MEDUSA HEAD Elymus caput-medusae ELCA13 68-69 YELLOW STARTHISTLE Centaurea solstitialis CESO3 34-35 Look-alike RUSH SKELETONWEED Chondrilla juncea CHJU 36-37 J SQUIR RELTAIL Elymus elymoides ELEL5 70-71 STINK WORT Dittrichia graveolens DIGR3 38-39 OTHERS MUSTARDS AND LOOK-ALIKES L Invasive L Invasive KLAMATH WEED Hypericum perforatum HYPE 72-73 DYER’S WOAD Isatis tinctoria ISTI 40-41 Look-alike HOARY CRESS Lepidium draba LEDR 42-43 J SCOULER’S ST. JOHNSWORT Hypericum scouleri HYSC5 74-75 PERENNIAL PEPPERWEED Lepidium latifolium LELA2 44-45 Invasive WHITE SWEETCLOVER Melilotus albus MEAL12 46-47 L SULFUR CINQUEFOIL Potentilla recta PORE5 76-77 K Look-alike Look-alike YAR ROW Achillea millefolium ACMI2 48-49 J SLENDER CINQUEFOIL Potentilla gracilis POGR9 78-79 L Invasive TEA SEL Dipsacus fullonum DIFU2 80-81 TREE OF HEAVEN Ailanthus altissima AIAL 82-83 6 7 QUICK REFERENCE ID QUICK REFERENCE ID
THISTLES Flower Head Leaves KNAPWEEDS Bracts Lower Leaves
Diffuse Bull Thistle Knapweed rough, deeply vase prominent spiny combs lobed veins
Russian Canada Thistle lobed, Knapweed drop spiny papery lobed
Musk Thistle midrib, Spotted disk hairless Knapweed deeply spots lobed
Scotch Thistle cobweb oval hairy Aster spp. (look-alike) no spines, narrow, yellow disk entire
Anderson’s Thistle small cylinder flat hairs Bachelor’s (look-alike) Buttons narrow, (look-alike) no spots entire Elk Thistle (look-alike) long no stems hairs
8 9 QUICK REFERENCE ID QUICK REFERENCE ID
YELLOW ASTERS Bracts Stems TOADFLAX Flower Spur Leaves
Dalmatian long, Yellow leaves ovate, Toadflax somewhat tips pointed, Starthistle curved or clasp stem straight lateral long, stout spines spines winged straw colored at base stem Yellow long, straight leaves linear, Toadflax sometimes pointed at Flowers/Plant Stems slightly both ends curved
bottom Rush of stem Skeletonweed with stiff Snapdragon no spur lower leaves downward lanceolate mostly smooth, pointing (look-alike) hairless hairs
BROOMS Seed Pods Leaves Stems Stinkwort
Scotch sticky-glandular, densely smells of camphor branched Broom only 3 leaflets, sharply margins sometimes 5 angled hairy simple
Spanish Broom round hairy simple finely ribbed
10 11 BULL THISTLE Cirsium vulgare CIVU Non-native Invasive
Tops of leaves rough, sandpaper texture
Underside of leaf cottony, prominently raised main vein
1 - 1.5 in
Plant, Brenneman; Flower, Donaldson Plant, Brenneman; Flower, Flower head vase-shaped
Rosette leaves rough, prominent veins Also Known As Common thistle Origin Eurasia Height: 1 - 6 ft, Habitat Meadows, roadsides, disturbed sites commonly 2 - 3 ft Life Cycle Biennial n Stems: spiny and winged Flowering Time Mid-July to fall n Leaves: sandpaper texture, Relative Abundance Widespread prominent veins Management Dig, removing top 2 inches of root; n Flowers: in clusters at herbicides are available ends of branches Noxious Weed List Nevada NO; California C-rated n Flower color: pink to purple 12 13 CANADA THISTLE Cirsium arvense CIAR4 Non-native Invasive
Bracts small and flat against head, tips weak
0.5 in Flower head Donaldson drop-shaped
Leaves deeply lobed
Also Known As Field thistle Origin Europe Height: 1.5 - 4 ft, commonly 2 - 3 ft Habitat Roadsides, rangelands, forests, lawns, gardens, moist and disturbed sites n Stems: smooth and ridged with no spines Life Cycle Perennial; reproduces from creeping roots and seeds n Leaves: smooth and sessile Flowering Time Mid-July to fall Relative Abundance Infrequent n Flowers: multiple small flower heads in Management Aggressive; pulling and burning favor clusters on each stem root resprouting; chemical control is needed n Flower color: light purple to white Noxious Weed List Nevada C-rated; California B-rated 14 15 MUSK THISTLE Carduus nutans CANU4 Non-native Invasive
Bracts large and spiny; purplish in color
2 - 3.5 in
Flower head disk-shaped
Light-green Rosette leaves hairless, midrib Plant, Miller; Flower, Donaldson Plant, Miller; Flower, light-green midrib, whitish margins
Also Known As Nodding thistle Height: 1 - 6 ft Origin Europe commonly 3 - 4 ft Habitat Pastures, forest, rangelands, n Stems: spiny and winged roadsides, waste areas, ditches n Leaves: hairless, prominent Life Cycle Biennial light-green midrib Flowering Time Mid-July to fall n Flowers: single, very large Relative Abundance Infrequent flower at end of bent, naked stem Management Dig, removing top 2 inches of root; herbicides are available n Flower color: deep pink to purple Noxious Weed List Nevada C-rated; California A-rated 16 17 SCOTCH THISTLE Onopordum acanthium ONAC Non-native Invasive
Many spiny, needle-like bracts
Leaves hairy, giving a grayish appearance 1-2 in Flower head flattened globe
Donaldson Stems spiny and winged
Also Known As Winged thistle Height: up to 10 ft, Origin Europe commonly 5+ ft Habitat Waste areas, roadsides, disturbed soils (the tallest of the thistles) Life Cycle Biennial; rarely annual Stems: spiny, prominently winged Flowering Time Mid-July to fall Leaves: hairy and sessile Relative Abundance Infrequent Flowers: in groups of 2 or 3 Management Dig, removing top 2 inches of root; on branched tips herbicides are available Flower color: purple Noxious Weed List Nevada C-rated; California A-rated 18 19 ANDERSON’S THISTLE Cirsium andersonii CIAN Native Look-alike
0.75 - 1.5 in
Brenneman Flower head cylinder-shaped Leaf margins wavy and spiny
Rosette leaves not prominently veined, small flat hairs
Also Known As Rose thistle Height: 2 - 4 ft Origin Native n Stems: purplish and Habitat Open places, woodlands, forests thornless Life Cycle Biennial n Leaves: divided and wavy Flowering Time July to fall with spiny margin Relative Abundance Widespread n Flowers: single Management Desirable native plant; do not disturb flower at end of stem Noxious Weed List None, Native n Flower color: rose red to reddish purple
20 21 ELK THISTLE Cirsium scariosum CISC2 Native Look-alike
Stemless flower Brenneman
Rosette leaves have long golden hairs; long fine spines at leaf margins
Height: up to 3 ft, Also Known As Drummond’s thistle generally less than 1 ft Origin Native n Stems: usually no stems; Habitat Moist places at mid to high elevations forms round flat rosette Life Cycle Biennial n Leaves: lobed, somewhat Flowering Time June to August spiny, pale green foliage Relative Abundance Moderate n Flowers: extend directly Management Desirable native plant; do not disturb from rosette Noxious Weed List None, Native n Flower color: white to pale lavender
22 23 DIFFUSE KNAPWEED Centaurea diffusa CEDI3 Non-native Invasive
Bract tips spiny; margins divided like teeth of comb
Upper leaves narrow and entire Donaldson
Stems stiff and widely branching
Lower leaves Also Known As Tumble knapweed deeply lobed Origin Southeastern Eurasia
Habitat Roadsides, waste areas, dry Height: 1 - 2.5 ft rangelands, disturbed sites n Stems: rough to touch Life Cycle Annual to short-lived perennial n Leaves: upper, entire; Flowering Time June to August lower, deeply lobed Relative Abundance Infrequent n Growth form: maintains Management Minimize seed production; pull or dig bush shape; after frost, plants several times per year and can break off and tumble monitor for several years; herbicides are available n Flower color: white to pale pink Noxious Weed List Nevada B-rated; California A-rated 24 25 RUSSIAN KNAPWEED Acroptilon repens ACRE Non-native Invasive
Bract margins papery, NOT spiny
Upper leaves narrow and entire Donaldson
Stems openly branched
Lower leaves lobed
Also Known As Creeping knapweed Height: 1 - 3 ft, Origin Central Asia generally 2 - 3 ft Habitat Roadsides, riverbanks, ditches, pastures, waste places n Stems: erect, cobwebby Life Cycle Perennial; reproduces from creeping roots n Leaves: upper, entire; lower and rosette, lobed Flowering Time July to fall Growth form: thick Relative Abundance Infrequent n rounded clumps with Management Cut or mow prior to seed set to reduce drooping branches current year’s growth; chemical control is needed n Root: black below crown Noxious Weed List Nevada C-rated; California B-rated n Flower color: pink to purple 26 27
SPOTTED KNAPWEED Centaurea stoebe CEST8 Non-native Invasive
Bract tips dark, finely fringed, spineless
Upper leaves narrow and entire Plant, Breckenridge CDFA; Flower, Donaldson Flower, Plant, Breckenridge CDFA;
Lower leaves deeply lobed Stems openly and smooth branched Note leaf Also Known As Centaurea stoebe placement Origin Europe Habitat Disturbed soil, rangelands, pastures, meadows, roadsides, areas with Height: 1 - 5 ft; summer rainfall generally closer to 3 ft Life Cycle Perennial; sometimes biennial, n Stems: erect and rough can reproduce vegetatively from roots n Leaves: upper, linear; Flowering Time July to early September lower, divided Relative Abundance Moderate n Growth form: tall with Management Chemical control is needed open branching Noxious Weed List Nevada A-rated; California A-rated n Flower color: pink to purple
28 29 AMERICAN- ASTER Symphyotrichum spp. Native Look-alike
Bracts do not have spines
Donaldson Leaves narrow and entire
Also Known As Various Height: variable, often 1 - 2 ft Origin Native n Stems: smooth to hairy Habitat Meadows, gardens n Leaves: upper and lower Life Cycle Annual or perennial leaves narrow and entire Flowering Time Late July to fall n Growth form: ranges from Relative Abundance Widespread short to tall Management Desirable native plant; do not disturb n Flower color: variable, Noxious Weed List None, Native often pink to purple with yellow center
30 31 BACHELOR’S BUTTONS Centaurea cyanus CECY2 Non-native Look-alike
Bract tips pale, finely fringed, spineless Donaldson
Leaves narrow and entire; generally not toothed except lower leaves
Also Known As Cornflower Origin Southern Europe, can be invasive, has escaped from cultivation Height: up to 3 ft Habitat Disturbed grasslands, open woods, n Stems: erect and branching ornamental plantings n Leaves: grayish and hairy; Life Cycle Annual upper and lower leaves Flowering Time July to September narrow and entire
Relative Abundance Widespread n Growth form: tall, bushy Management Mechanical controls (pull, dig, hoe); herbicides are available n Flower color: multicolored (white, blue, purple, Noxious Weed List Nevada NO; California NO pink, red) 32 33 YELLOW STARTHISTLE Centaurea solstitialis CESO3 Non-native Invasive
Long, stout, straw-colored spines at tips of bracts (up to 1 in. long)
Upper leaves entire Donaldson Stems Stems winged winged Lower leaves deeply lobed
Also Known As None Height: 0.5 - 5 ft, Origin Southern Europe commonly 2 ft Habitat Roadsides, waste areas, grasslands n Stems: winged Annual Life Cycle n Leaves: gray and hairy; Flowering Time Late June to September upper, entire; Relative Abundance Infrequent lower, deeply lobed Management Pull, dig or mow at first sign of yellow n Growth form: stiffly flowers; herbicides are available branching Noxious Weed List Nevada A-rated; California C-rated n Flower color: yellow
34 35
RUSH SKELETONWEED Chondrilla juncea CHJU Non-native Invasive
Lower 4 - 6 inches of stem has downwardly bent coarse hairs DiTomaso
Rosette leaves sharply toothed
Milky juice in stems and leaves Stems smooth Also Known As Skeleton weed, hogbite above Origin Southern Europe Habitat Roadsides, rangelands, pastures, Height: 1 - 4 ft disturbed soils n Stems: rigid and wiry; Life Cycle Perennial with extensive, deep root highly branched; cut system surfaces exude milky sap Flowering Time Mid-July through frost n Leaves: upper, narrow Relative Abundance Infrequent and entire, inconspicuous; Management Digging and pulling will favor root stems often lack leaves sprouting and regrowth; herbicides n Growth form: bushy available n Flower color: yellow Noxious Weed List Nevada A-rated; California A-rated 36 37 STINK WORT Dittrichia graveolens DIGR3 Non-native Invasive
Bracts in Single flower several heads grow at overlapping ends of branches; rows and in leaf axils
Plant sticky-glandular; smells strongly of camphor
(Can cause allergic contact dermatitis; recommend gloves if handling!) Plant, King; Flower, Williams Plant, King; Flower,
Seed ~ 1/8 in. long Also Known As None Height: 0.5 - 3 ft Habitat Meadows, roadsides, waste places, gardens n Stems: many-branched, sticky-glandular Origin Southern Europe n Leaves: narrow, alternate, Life Cycle Annual reduced upwards, and Flowering Time September to November sticky-glandular Relative Abundance Moderate n Flower heads: single Management Dig or hand pull (wear protective flower heads grow at ends of branches; and in clothing to avoid contact with skin); leaf axils herbicides available n Flower color: yellow Noxious Weed List Nevada NO; California B-rated 38 39
DYER’S WOAD Isatis tinctoria ISTI Non-native Invasive
Fruits black to dark purple; hang like pendants from stem
Tiny 4-petaled flowers in dense clusters near ends of branches
Plant, Welch; Flower, Belsher-Howe Flower, Plant, Welch; Lobes clasp stem on upper leaves
Long petiole on Rosette leaves rosette leaves oblanceolate with Also Known As Marlahan mustard weakly rounded tips Origin Europe Height: up to 4 ft. Habitat Meadows, roadsides, streambanks, rangelands n Stems: single stem gives rise to multiple branches Life Cycle Biennial to short lived perennial with multiple flower clusters Flowering Time June to July n Leaves: blue-green foliage Relative Abundance Infrequent with cream-colored midrib; Management Dig, removing top 2 inches of root; upper leaves clasp stem, observe site yearly to look for sprouting arrowhead-shaped; rosettes; herbicides are available lower leaves petiolate Noxious Weed List Nevada A-rated; California B-rated n Flower color: yellow
40 41
HOARY CRESS Lepidium draba LEDR Non-native Invasive
Single stem
Tiny 4-petaled flowers in dense clusters near ends of branches 2 lobes Donaldson clasp stem on upper leaves
Leaves lance-shaped
Also Known As Whitetop, short whitetop Origin Eurasia Habitat Meadows, fields, roadsides, ditches, Height: up to 2 ft, streambanks, rangelands commonly 1 ft Perennial; reproduces from creeping roots Life Cycle n Stems: single stem gives Flowering Time May to June rise to one flower cluster Relative Abundance Infrequent n Leaves: blue-green foliage; Management Do not pull as plants will grow from root upper leaves clasp stem; fragments; chemical control is needed lower leaves petiolate Noxious Weed List Nevada C-rated; California B-rated n Flower color: white 42 43 PERENNIAL PEPPERWEED Lepidium latifolium LELA2 Non-native Invasive
multiple branches
Tiny 4-petaled flowers in dense clusters near ends Donaldson of branches
Stems branch from juncture of leaf with main stem Leaves lance-shaped; leaf margins smooth or toothed
Also Known As Tall Whitetop Origin Eurasia Habitat Riparian areas, floodplains, meadows, Height: 1 - 6 ft, seasonally wet areas, roadsides commonly 3+ ft Life Cycle Perennial; reproduces from creeping Stems: multiple branches roots and root fragments grow from each stem Flowering Time Late June to August Leaves: upper leaves, Relative Abundance Moderate sessile; lower leaves, petiolate; basal leaves, Management Do not pull, dig, or cut the roots, much larger than upper as this may stimulate new growth; leaves chemical control is needed n Flower color: white Noxious Weed List Nevada C-rated; California B-rated 44 45 WHITE SWEETCLOVER Melilotus albvus MEAL12 Non-native Invasive
Many small fragrant flowers Pea-shaped borne on flowers irregular spikes at the ends of elongated stems Brenneman
Leaves consist of 3 leaflets, margins finely toothed
Also Known As None Origin Non-native, used in soil stabilization mixes Habitat Roadsides, waste areas Height: 2 - 6 ft. Life Cycle Annual to biennial commonly about 3 - 5 ft. Flowering Time June to August n Stems: well-branched and Relative Abundance Widespread coarse Management Hand pull wearing gloves; dig or mow n Leaves: 3 leaflets prior to seed set; herbicides available Flower color: white Noxious Weed List Nevada NO; California NO n 46 47 YAR ROW Achillea millefolium ACMI2 Native Look-alike
Flower heads flattened, dome-shaped corymbs
Leaves hairy and very finely pinnately
Plant, Brenneman; Flower, Donaldson Plant, Brenneman; Flower, divided, appearing feather-like
Also Known As Common yarrow, milfoil Origin Native and introduced, can be invasive Habitat Gardens, meadows, grasslands, forests Life Cycle Perennial Height: 2 - 3 ft Flowering Time June to September n Stems: hairy-wooly Relative Abundance Widespread n Leaves: feather-like; evenly Dig, removing as much root as Management distributed along stem; possible; forms dense mat if mowed; lower leaves larger chemical control is available n Flower color: white or pink Noxious Weed List None, Native 48 49 DALMATIAN TOADFLAX Linaria dalmatica LIDA Non-native Invasive
Leaves ovate, Spurs long, tips pointed somewhat curved or straight Donaldson
Flowers borne in axils of upper leaves and bracts
Leaves clasp stem Also Known As Wild snapdragon, Linaria genistifolia ssp. dalmatica Height: up to 3 ft Origin Mediterranean Habitat Roadsides, pastures, rangelands, Stems: erect and branched cultivated fields Leaves: ovate, alternate Life Cycle Perennial and entire; succulent and waxy Flowering Time July to fall Growth form: more Relative Abundance Moderate scattered than yellow Management Pull or dig for several years, removing toadflax as much root as possible; do not mow; chemical control is available Flower color: yellow, with orange, bearded throat Noxious Weed List Nevada B-rated; California A-rated 50 51 YELLOW TOADFLAX Linaria vulgaris LIVU2 Non-native Invasive
Spur Plant, Brenneman; Flower, Charles Webber © CA Academy Charles Webber Plant, Brenneman; Flower, of Sciences
Leaves linear, pointed at both ends Leaves alternate, crowded close together
Also Known As Butter and eggs Origin Mediterranean Height: 1 - 2 ft; Habitat Rangelands, roadsides, waste places, shorter than dalmatian cultivated fields toadflax Life Cycle Perennial Leaves: linear, smooth to Flowering Time July to fall sparsely hairy; succulent and waxy Relative Abundance Moderate Growth form: tends to Pull or dig for several years, removing Management grow in crowded patches as much root as possible; do not mow; chemical control is available Flower color: yellow, with orange, bearded throat Noxious Weed List Nevada A-rated; California NO 52 53 SNAP DRAGON Antirrhinum majus ANMA3 Non-native Look-alike
Flowers in terminal racemes
No spur Plant, Brenneman; Flower, Donaldson Plant, Brenneman; Flower,
Upper leaves long and narrow Lower leaves lanceolate
Also Known As None Origin Non-native Habitat Ornamental gardens Height: 0.5 - 3 ft Annual to perennial Life Cycle n Leaves: upper, long and Flowering Time June to fall narrow; lower, lanceolate; Relative Abundance Widespread soft, not waxy n Flowers: fuzzy-hairy Management None; recommended garden flower Noxious Weed List Nevada NO; California NO n Flower color: yellow, but other colors are available
54 55 OXEYE DAISY Leucanthemum vulgare LEVU Non-native Invasive
Leaves spoon-shaped Upper leaves toothed, sessile; smaller towards top of stem
Approximate disk flower to ray flower ratio
Lower leaves lobed or toothed Donaldson Rosette leaves spatulate; margins crenulate
Height: 0.8 - 2 ft
Also Known As White daisy n Stems: smooth to slightly hairy Origin Europe n Leaves: upper, toothed Habitat Meadows, roadsides, waste places, and sessile; lower, gardens pinnately lobed or toothed Life Cycle Perennial n Flowers: single flower Flowering Time June to August heads grow at ends Relative Abundance Widespread of branches; bracts are lined in black Management Pull or dig before seed production; herbicides are available n Flower color: white with yellow center Noxious Weed List Nevada NO; California NO 56 57 SHASTA DAISY Leucanthemum maximum LEMA8 Non-native Look-alike
Upper leaves serrate and sessile; smaller toward top of stem
Approximate disk flower to ray flower ratio Rosette leaves oval; margins serrate Plant, Brenneman; Flower, Donaldson Plant, Brenneman; Flower,
Height: 1 - 3 ft, taller than oxeye daisy Also Known As None n Stems: stiff, more-or-less smooth Origin Non-native, naturalized n Leaves: upper, serrate and Habitat Well-drained soil, full sun, sessile; lower, petiolate ornamental gardens Life Cycle Perennial n Flowers: single flower heads grow at ends Flowering Time July to September of branches; heads Relative Abundance Widespread larger than oxeye daisy Management None; recommended garden flower n Flower color: white Noxious Weed List Nevada NO; California NO with yellow center
58 59 SCOTCH BROOM Cytisus scoparius CYSC4 Non-native Invasive
Flowers single or paired in leaf axils
Numerous showy pea flowers
Seed pods flattened, only margins hairy Plant, VanZuuk; Flower, Keir Morse Flower, Plant, VanZuuk;
3 leaflets, sometimes simple Stems sharply 5-angled Also Known As Common broom, English broom Height: woody shrub Origin Europe and north Africa up to 8 ft. Habitat Pastures, forests, waste areas n Stems: 5-angled; star-shaped cross-section Life Cycle Long lived perennial Flowering Time May to July n Branches: dark green; more-or-less erect Relative Abundance Moderate Management Pull with heavy-duty weed wrench n Leaves: 3 leaflets, removing as much root as possible: sometimes simple on observe site yearly and pull seedlings; new twigs, deciduous chemical control most effective treatment n Flower color: deep yellow; Noxious Weed List Nevada NO; California C-rated slight to no fragrance 60 61 SPANISH BROOM Spartium junceum SPJU2 Non-native Invasive
Flowers in open racemes at stem tips
Numerous showy pea flowers Seed pods slightly flattened, densely covered with long hairs Stems finely Donaldson ribbed, round in cross-section
Leaves simple
Also Known As Weaver’s broom Height: woody shrub Origin Mediterranean up to 8 ft. Habitat Roadsides, forests and rangelands n Stems: smooth or finely Life Cycle Long lived perennial ribbed; round cross- Flowering Time May to July section n Branches: dark green; Relative Abundance Moderate more-or-less erect
Management Pull with heavy-duty weed wrench Leaves: simple, entire; removing as much root as possible: sparse and deciduous observe site yearly and pull seedlings; chemical control most effective treatment n Flower color: yellow; Noxious Weed List Nevada NO; California C-rated strong fragrance
62 63 BARBED GOATGRASS Aegilops triuncialis AETR Non-native Invasive
3 long, straight awns
Huhndorf Spikelet
Seed head
Fertile spikelets Spikelet occur at base of plant in addition to seed heads Also Known As None Habitat Rangelands, roadsides, disturbed places Height: 1 - 2 ft Origin Mediterranean, Europe, western Asia Seed head: spikelets fall Life Cycle Annual from plant intact, not Flowering Time May to July leaving a central axis Relative Abundance Moderate Awns: each spikelet has Management Handpull; herbicides available 3 long straight awns Noxious Weed List Nevada A-rated; California B-rated Growth form: ranges from a single stem to a bunch with many stems 64 65 JOINTED GOATGRASS Aegilops cylindrica AECY Non-native Invasive
Short awns
Each spikelet Spikelet will fall separately
Seed head narrow, cylindrical Spikelet Huhndorf
Spikelets at base of plant less common than in barbed goatgrass
Spikelet Also Known As None Habitat Roadsides, disturbed, dry places, cultivated fields Height: 1 - 2 ft Origin Mediterranean, Europe, western Asia Seed head: spikelets fall Life Cycle Annual from plant intact, not Flowering Time May to July leaving a central axis Relative Abundance Infrequent Awns: very short except Management Handpull; herbicides available for on the top spikelet Noxious Weed List Nevada A-rated; California B-rated Growth form: ranges from a single stem to a bunch with many stems 66 67 MEDUSA HEAD Elymus caput-medusae ELCA13 Non-native Invasive
Awns
Seed Glumes head
Awn Huhndorf Glume
When mature, seeds fall from the head, leaving long glumes in place
Central axis Seeds
Height: 1 - 2 ft Also Known As Taeniatherum caput-medusae Seed head: central axis with Habitat Rangelands, roadsides, glumes persist into winter disturbed places Upper awns long and wavy, Origin Europe 1.12 - 4 in; lower glumes Life Cycle Annual shorter, 0.2- 3.14 in Flowering Time April to July Growth form: ranges from Relative Abundance Common a single stem to a bunch with many stems Management Rake and remove existing thatch, handpull small infestations; herbicides available Key feature: very long, Noxious Weed List Nevada B-rated; California C-rated upward-pointing, wavy awns 68 69 SQUIR RELTAIL Elymus elymoides ELEL5 Native Look-alike
Seed head When mature, Glumes seed heads break and awns, apart into sections, not leaving a central Huhndorf approximate Awn equal length axis behind
Glume Young Seeds seed head Height: 1 - 2 ft Seed head: spikelets fall from plant intact, not Also Known As Bottlebrush leaving a central axis Habitat Forests, grasslands, most plant Glumes and awns: approx. communities equal length, 0.6 - 4.7 in; Origin Native often reddish when young, Life Cycle Perennial straw-colored when mature Flowering Time June to August Growth form: generally in bunches with several to Relative Abundance Common many stems Management None Key feature: glumes and Noxious Weed List None, Native awns bent to nearly 70 71 horizontal when mature KLAMATH WEED Hypericum perforatum HYPE Non-native Invasive
Older flower petals twist
5 separate petals
Occasional tiny black dots at Flat-topped edges of petals cymes
More flowers per 1 in stem than native Brenneman Transparent dots on leaves; leaf shape narrow/oblong
Leaf margins rolled under Height: 1 - 3+ ft Also Known As St. John’s Wort n Stems: erect with numerous Origin Europe rust-colored branches Pastures, meadows, roadsides, Habitat n Leaves: narrowly oblong, waste areas entire, opposite, sessile; Life Cycle Perennial not over 1 in long Flowering Time June to late September n Growth form: bushy Relative Abundance Moderate n Branches: somewhat Management Pull or dig repeatedly; use biocontrol 2-ridged and woody at insects; chemicals are available the base Noxious Weed List Nevada A-rated; California C-rated n Flower color: yellow 72 73 Hypericum SCOULER’S ST. JOHNSWORT scouleri HYSC5 Native Look-Alike
5 separate petals
Tiny black dots at edges of petals
1 in
Fewer flowers per stem than Plant, Eliassen Calphotos ; Flower, Matson Calphotos Plant, Eliassen Calphotos ; Flower, Leaf margins invasive black-dotted, lower surface inconspicuously dotted; leaf shape rounder than Klamathweed
Also Known As None Height: 0.5 - 2.5 ft Origin Native Habitat Streambanks, meadows n Stems: slender; extend from base Life Cycle Tap-rooted perennial n Leaves: ovate/elliptic Flowering Time Summer flat, more or less clasping Relative Abundance Moderate n Growth form: upright Management Desirable native plant; do not disturb and stemmy Noxious Weed List None, Native n Flower color: yellow
74 75 SULFUR CINQUEFOIL Potentilla recta PORE5 Non-native Invasive
Flowers 5 petals
Stems branch only in the inflorescence Bud
Both long spreading and very short hairs DiTomaso
Leaves palmately compound with 5 - 7 divisions (6 - 7 common)
Also Known As Roughfruit cinquefoil Height: 2 ft Origin Eurasia n Stems: hairs glandular, almost appearing shiny Habitat Roadsides, pastures, rangeland, wildlands, disturbed areas n Leaves: upper and lower surfaces stiff-hairy; Life Cycle Tap-rooted perennial undersides green (not Flowering Time May to July silvery like most potentillas); Relative Abundance Infrequent hairs glandular, almost appearing shiny Management Dig, removing as much root as possible; herbicides are available n Growth form: shrub
Noxious Weed List Nevada A-rated; California A-rated n Flower color: light yellow 76 77 SLENDER CINQUEFOIL Potentilla gracilis POGR9 Native Look-Alike
Flowers 5 petals
Bud
Hairs of only one
Plant, Charters, CalPhotos; Flower, DiTomaso Plant, Charters, CalPhotos; Flower, length
Leaves palmately compound with 5 - 7 divisions
Also Known As Graceful cinquefoil, western cinquefoil Native Origin Height: to 2.5 feet tall Habitat High mountain meadows, open n Stems: have hairs of only forests one length Life Cycle Perennial n Leaves: hairy, especially Flowering Time July to August below; undersides Relative Abundance Widespread gray-green, silvery; leaf Management Desirable native plant; do not disturb margins evenly toothed Noxious Weed List None, Native n Flower color: yellow
78 79 TEA SEL Dipsacus fullonum DIFU2 Non-native Invasive
Flowers in dense egg-like heads with large, spine-like bracts
Ridges lined with stiff prickles DiTomaso
Leaves paired, fused at base around stem Stiff prickles on lower midrib
Height: to 7 feet tall, Also Known As Common teasel, wild teasel commonly 3+ feet Origin Europe n Stems: branched, rough and spiny Habitat Irrigation ditches, canals, wetlands, riparian areas, disturbed sites n Leaves: conspicuously Life Cycle Tap-rooted biennial veined; stem leaves lanceolate and up July to fall Flowering Time to 10 inches long Relative Abundance Infrequent n Growth form: erect Management Dig or hand-pull, removing as much root as possible; herbicides are available n Flower color: lavender to purple, rarely white Noxious Weed List Nevada NO; California NO 80 81 TREE OF HEAVEN Ailanthus altissima AIAL Non-native Invasive Plant, Williams; Flower, T. Hanson T. Plant, Williams; Flower,
Teeth Top of leaflet Underside Opposite leaflets Gland-tipped teeth at the base of each leaflet Leaf distinguish from sumac, which looks similar when young Fruit with seed near middle, Also Known As Stink tree clusters of 1 - 5 Habitat Disturbed areas, riparian areas, Sapling often near old habitations Origin China Height: tree up to 60 ft Life Cycle Tree; perennial; reproduces from Bark: smooth and pale gray creeping roots and seeds Leaves: up to 3 ft long, Flowering Time June with 11 - 25 leaflets; Relative Abundance Infrequent foul-smelling when crushed Management Hand pull seedlings; weed wrench Flower color: greenish saplings, but must extract entire root; Fruits: clusters of herbicides available reddish-brown winged Noxious Weed List Nevada NO; California C-rated fruits in September 82 83 GLOSSARY GLOSSARY
Alternate: Borne singly at each node, such as leaves. Ovate Leaf: Egg-shaped leaf that is attached at the broad end. Awn: A thin, bristle-like extension, often part of a grass seed head. Palmate: Having three or more veins or lobes radiating Axil: The point formed between the stem and any part, from a central point, similar to the fingers on a hand. such as a leaf, attached to it. Panicle: A branched inflorescence in which the flowers Bract: A modified leaf at the base of a flower. bloom from the bottom up. Corymb: A flat-topped or round-topped arrangement of Petiole: The stalk of a leaf. flowers where the lower flower stalks are longer than the Pinnate: A compound leaf with leaflets arranged on upper stalks. opposite sides of the axis. Crenulate: Having very small, rounded teeth on the leaf margin. Raceme: A simple, elongated arrangement of flowers. Cyme: A flat-topped or round-topped arrangement of Ray flower: The long, narrow flower that radiates flowers in which the terminal flower blooms first. outward from the disk flower in the Asteraceae family. Disk flower: The tiny, tubular flower of the Asteraceae that Each ray flower resembles a single petal. forms the center disk of the flowerhead. Rhizomatous: Having rhizomes, or horizontal underground Divided: Deeply lobed leaf in which lobes are indented to stems that produce shoots above and roots at distinct nodes. the base or the midrib. Rosette: A dense, basal cluster of leaves arranged in a Elliptic: Shaped like an ellipse or a narrow oval, broadest in circular fashion around one point, usually at ground level. the middle. Serrate: With sharp teeth directed forward; generally Entire: The margins are smooth, without teeth or lobes. refers to leaf edges. Glume: Sterile bract or bracts at the base of a grass spikelet. Sessile: Without a stalk of any kind; for example, a leaf directly attached to a stem. Inflorescence: A flower cluster. Spatulate: Shaped like a spatula, with a rounded blade Linear: Narrow and flat with sides or edges parallel, as in a leaf. that tapers to the base. Lobed: Bearing lobes cut less than halfway to base or midvein. Spike: An unbranched, long flower stalk in which the Margin: The outer edge of the leaf, which may be smooth, flowers attach directly to the stem and mature from the serrated, lobed, etc. bottom upwards. Midrib: The middle vein of a leaf. Spikelet: In grasses, the basic unit of the seed head, Oblanceolate: leaf shape in which the length is at least 3x sometimes falling intact from plant. longer than wide, but broadest above middle. Toothed: Having sharp points or lobes along a margin, Oblong: Leaf shape in which the leaf is two to four times as on a leaf. longer than it is wide, with nearly parallel sides. Umbel: A flat-topped flower arrangement. Opposite: Leaves or other structures borne across from Winged stem: A stem with one or more thin, flat each other at the same node. margins protruding along the length of the stem. 84 85 ADDITIONAL RESOURCES REPORTING & CONTACT INFORMATION
State and Federal Noxious Weed Lists To report a weed sighting online, or to contact the Nevada Department of Agriculture Lake Tahoe Basin Invasive Weed Coordinating Group, agri.nv.gov/Plant/Noxious_Weeds/Noxious_Weeds_Home go to tahoeinvasiveweeds.org. California Department of Food & Agriculture To report weeds or for control recommendations: cdfa.ca.gov/plant/ipc/encycloweedia/encycloweedia_hp.html Nevada U.S. Department of Agriculture - Federal Noxious Weed List Douglas County Weed District (775) 782-9835 plants.usda.gov/java/noxious Washoe County Weed Reporting (775) 784-4848 washoeweeds.org Plant Photos, Plant Distribution, Smartphone Mapping Applications California Lake Tahoe Basin Weed Coordinating Group Placer County Agriculture Department (530) 889-7372 tahoeinvasiveweeds.org El Dorado County Agriculture Department (530) 621-5520 Calflora calflora.org For homeowner site visits: CalWeedMapper calweedmapper.cal-ipc.org Tahoe Resource Conservation District (530) 543-1501 EDDMapS West eddmaps.org/west (California) Ext. 113
California Invasive Plant Council cal-ipc.org Nevada Tahoe Conservation District (775) 586-1610
Plant Ecology and Treatment Information FUNDED BY: University of California Weed Research & Information Center Lake Tahoe License Plate wric.ucdavis.edu Program & Nevada Division Techline Invasive Plant News techlinenews.com of State Lands
Aquatic Invasive Weeds Tahoe Resource Conservation District tahoercd.org Tahoe Resource Conservation Tahoe Regional Planning Agency trpa.org District League to Save Lake Tahoe keeptahoeblue.org
Nevada US Forest Service, Department State and Private of Agriculture Forestry Program
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