Invasive Plant Species In Bidwell Park -- Friends of Bidwell Park

Potentially Invasive Plant Species In Bidwell Park

Preliminary list-- the Bidwell Park and Playground Commission will make any final determinations as to inclusion and ranking of plants

Listed? IPC CA BC	Blooming Period	Locations	Dispersal Agents	Photo Link	Habitats / Comments
Plants ranked #1 on park priority list: Highly invasive. Should have immediate management
Algerian ivy Hedera canariensis	H	Mid-Sept	Lower and Middle Park	Vegetative, birds		Riparian, woodland, encroaching from neighboring residential properties
American pokeweed Phytolacca americana	L	Early Jul-Oct.	Lower and Middle Park	Birds		Riparian; spreading rapidly in Bidwell Park, becoming a fairly common weed in the Chico Urban Area.
Barbed goatgrass Aegilops triuncialis	H B	Early May	Upper Park 100' east of start of Middle Trail by Lot A, Pine Trailhead, Guardian Trail by Pine Trail	wind	CDFA	Only a few infestations, should eradicate before it spreads
Bladder senna Colutea arborescens		Late May-Jun.	Lower Park; Cedar Grove, Five Mile	human, gravity; indehiscent		Riparian, Valley Oak Woodland; Came from 1 planting in 1890s. Control attempted in past, focused eradication program started by Friends of Bidwell Park in May, 2003 with about 1M plants removed so far. People spread seeds by "popping" pods as they walk through the park.
Broomsedge bluestem Andropogon virginicus		Early Sept.	Upper Park		GISD	Moist to wet soil along streams, on seeps, along ponds, in pastures. Native to eastern U.S., destroying park's wetlands
Edible fig Ficus carica	M *	Late Mar.-Apr.	Lower, Middle and Upper Park	Birds, Mammals		Riparian, very large trees near old cabin site on Ten Mile House Rd and in former deer pen
English ivy Hedera helix	H *	Mid-Sept.	Lower and Middle Park	Vegetative, birds	No Ivy League	Riparian, Valley Oak Woodland; mature ivy encroaching from many South Park Drive neighbors
French broom Genista monspessulana	H B	Late Mar.-Jul.	Middle Park by Hooker Oak Recreation Area	Gravity, Water		Riparian, Valley Oak, and Foothill Woodland; disturbed road edges;
French tamarisk Tamarix ramoissima	H B	Early Apr.-May	One plant in Upper Park upstream of Day Camp, Lindo Channel	Wind	TISI, TNC	Riparian; dispersed by millions of dust-like seeds
Garden (Salad) burnet Sanguisorba minor muricata		May-August	Upstream end of Upper Park			Extensive root system, need to control to prevent spread into BCCER
Giant reed, Arundo Arundo donax	H B *	Early Oct.	Lost Park, Lower and Middle Park, Lindo Channel	Spread by rhizomes moved during flooding	TISI, TNC	Riparian; control underway since 2000 by City of Chico; about 110 mapped sites, roots and rhizomes tenacious
Himalayan blackberry Rubus armeniacus	H *	Early May-June	Lower, Middle and Upper Park	Birds Mammals	TISI, TNC	Riparian-Valley Oak Woodland; can be confused with native blackberry, City of Chico uses Salt Creek Crews & goats for control
Italian plumeless thistle Carduus pycnocephalus	M C	Mid April-June	Guardian Trail, lower end of Yahi	wind, humans, animals	TISI, TNC	Grassland, Oak Woodland-three known populations--two on Guardian Trail by former BLM property, one on Yahi near start of trail
Japanese privet Ligustrum japonicum	*	Late spring-early summer	Lost Park, Camellia Way Park, Lower, Middle & Upper Park	Birds	TISI, TNC	Riparian, Valley Oak Woodland; Widely planted horticultural shrub, 264 mapped sites in park, eradication underway at Five Mile & in Lower Park
Klamath weed, St. John's wort Hypericum perforatum	M C	Late April-Oct	Upper Park			Grassland, Foothill Woodland
Medusahead grass Taeniatherum caput-medusae	H C	Late Mar.	Lower, Middle and Upper Park	Mammals	TISI, TNC	Annual Grassland; common grass in Upper Park; can be controlled with fire and grazing; some controlled burns done by City of Chico
Northern catalpa Catalpa speciosa		Early May	Lower and Upper Park			Riparian Woodland;
Olive Olea europaea	L	Late May-Jun.	Lower and Upper Park; old grove south of golf course	Birds		Riparian, Foothill Woodland; can form very dense canopies; spreading up canyon on both sides of creek
Perennial pepperweed, tall whitetop Lepidium latifolium	H B *	Early May-Sept.	Lower Park	Wind, Water, Animals?	TISI, TNC	Riparian; roots can exceed 20 feet in depth, small infestation removed at walnut orchard area in 2003
Periwinkle Vinca major	M *	Mid Jan.-Jul.	Lower, Middle and Upper Park	Vegetative	TISI, TNC	Riparian, Valley Oak Woodland; forms dense sprawling mats that smother all other understory species; displaces California Grape, Native Blackberry, Pipevine, etc.
Puncturevine Tribulus terrestris	C *	Early May-Oct.	Lower, Middle and Upper Park	Mammals (shoes and tires)		Disturbed road and trail margins; a painful nuisance to barefoot children, dogs, and troublesome to bicyclists
Southern catalpa Catalpa bignonioides	UC	Late spring-summer	Lower Park-Cedar Grove
Spanish broom Spartium junceum	H B *	Early Mar-Jul.	Upper Park	Gravity	TISI, TNC	Riparian, Valley Oak Woodland; Common and increasingly widespread on disturbed stream edges and along Hwy 32. Eradication projects conducted over 10 years by CNPS
Tree of heaven Ailanthus altissima	M UC *	Late Apr.-May	Lost Park, Annie's Glen, Lower and Middle Park	root sprouts, wind	TISI, TNC	Riparian, Valley Oak Woodland; Increasingly common and widespread tree
Yellow starthistle Centaurea solstitialis	H C *	Most months	Lower, Middle and Upper Park	Wind	TISI, TNC	Annual Grassland, openings in Woodland; abundant and widespread; can be controlled with fire and grazing
Plants ranked #2 on park priority list: Moderately invasive. Should provide management when possible
Black locust Robinia pseudoacacia	L	Mid April-May	Lower Park, Lost Park, Annie's Glen, Upper Park by Green Gate	Gravity, water, animals?	TISI, TNC	Widely naturalized along streams on the valley floor and in the foothills; scattered in lower coniferous forest. Native to eastern U.S.
Bouncingbet Saponaria officinalis	L	Late June-Oct	Upper Park
Bull thistle Cirsium vulgare	M C	Most months	Upper Park	Wind		Riparian areas, marshes and meadows
Bur-chervil Anthriscus caucalis		Early March-April	Lower, Middle and Upper Park	People and other animals		Should try to control in high-use areas and along trails
Canada thistle Cirsium arvense	M B	Late Jul.-Sept.		Wind	GISD	Troublesome in riparian areas, need to verify that it's in the park
Cheat grass, Downy brome Bromus tectorum	H	Early May	Lower, Middle and Upper Park	Mammals, Wind	TISI, TNC	Annual Grassland
Chinese hackberry Celtis sinensis				seed
Cork or rock elm Ulmus thomasii			Cedar Grove area			Very localized infestation--need to remove many of the smaller trees, girdling will leave areas of fire-prone dead 6-8' trees
Eastern or common hackberry Celtis occidentalis			Lower, Middle and Upper Park
European privet Ligustrum vulgare		Early spring-early summer	Lower and Middle Park	Birds	TISI, TNC
Italian aram Arum italicum		Early May	Lower Park	Vegetatively		Very prevalent in One Mile area especially east of Caper Acres, difficult to eradicate
Johnsongrass Sorghum halepense		Late May	Lower and Upper Park	Rhizomes	TISI, TNC	Moist to dry fields, orchards, lawns, roadsides, waste places. Native to Mediterranean.
Mediterranean hackberry Celtis australis		Apr.	Lower, Middle and Upper Park	Birds		Occasional small to median tree in the Chico Area, an apparent escape from the old Bidwell Forestry Station at Cedar Grove
Milk thistle Silybum marianum		Early March-June	Lower Park by Sycamore Pool, Upper Park by Horseshoe Lake		TISI, TNC	Should try to eradicate in high-use areas
Pennsylvania blackberry Rubus pensilvanicus		Mid May-July	Lower, Middle and Upper Park
Pyracantha, Chinese firethorn Pyracantha angustifolia	L	Late May-Jun	Lower Park	Birds		Riparian, Valley Oak Woodland
Red or foxtail brome Bromus madritensis ssp. rubens	H	Early June	Lower Park		TISI, TNC	Native to Australia
Silktree, mimosa Albizia julibrissin		summer and fall	Hooker Oak, near Lower Park walnut orchard		GISD	common Chico tree, spreads easily, seed viable for 50 years, should eradicate the few trees in the park to prevent spread
Smooth hawthorn Crataegus laevigata		Mid Apr.	Lower Park			A number of plants have volunteered at scattered locations in Bidwell Park from experimental plantings at the old Bidwell Forestry Station (now Cedar Grove) in Lower Park
Tall fescue Festuca arundinacea	M	Mid-April	Upper Park		TISI, TNC	Grassland, Foothill Woodland
Thornless (elmleaf) blackberry Rubus ulmifolius var inermis		Early May-June	Lower Park	Birds, vegetatively		Dense growth (about 30' x 150') at picnic site #8. Mentioned in Big Chico Creek Existing Conditions Report & Joe DiTomaso's Aquatic and Riparian Weeds of the West
Tocalote, Malta starthistle Centaurea melitensis	M C	Late Mar.-Jul.	Upper Park	Wind, Mammals	GISD	Annual Grassland, Foothill Woodland; occasional weed; can be confused with Yellow Star Thistle; old plants can flower in the Fall and early Winter
Tumbleweed, pigweed Amaranthus albus		Early May-Sept	Upper Park
Woolly or common mullein Verbascum thapsus	L	Early Mar.-Oct.	Lower and Upper Park	Wind	TISI, TNC	Riparian and disturbed areas in Woodlands; common along road edges in the County
Plants ranked #3 on park priority list: Low to moderately invasive. Should monitor.
Almond prunus dulcis		Mid Feb-Aprilo	Lower and Middle Park	squirrels
American elm Ulmus americana		Spring	Lower and Middle Park	Wind		Widely planted street tree. It volunteers freely along Big Chico Creek, particularly on the University campus, but so far has not been found outside the urban area. Native to eastern U.S.
Black mustard Brassica nigra	M		Upper Park			Grassland, Foothill Woodland
Brazilian pepper tree Schinus terebinthifolius	L		Cedar Grove		TISI, TNC
Camphor Cinnamomum camphora		Late spring	Lower Park	birds	CAIP, UoF	Spreads easily by seed, can create thousands of seedlings from one tree
Cherry or purple leaf plum Prunus cerasifera	L	Late Feb-Apr.	Lower, Middle and Upper Park	Birds		Widely naturalized along Sacramento River and other streams from the valley floor into foothill canyons. Native to southeast Europe.
Chinese pistache Pistacia chinensis	E	Late March-April	Lower, Middle and Upper Park	Birds		Very common in Lower Park; may want to eradicate female trees to prevent further spreading
Common myrtle Myrtle communis			4th St. entrance & along Woodland	birds		Doesn't seem to spread very quickly
Cotoneaster Cotoneaster franchet (?) pannosa (?)	M	Spring	Cedar Grove			Need to determine exact species
Field bindweed Convolvuulas arvensis	C	Early April-Oct	Upper Park		TISI, TNC	Grassland
Golden bamboo Phyllostachys aurea			Lower Park on S. Park Dr.	Wide-creeping rootstocks form solid stands		Small patches creeping in from adjoining residence on S. Park Dr and along path from E 8th St. entrance east of Hwy 99
Japanese honeysuckle Lonicera japonica		Early May-June	Lower Park		TISI, TNC
Mediterranean, hoary mustard Hirschfeldia incana	M	Most Months	Lower, Middle and Upper Park	Gravity, Wind		Annual Grassland, Riparian, Foothill Woodland; perennial weed of dry disturbed places
Moonwort Lunaria annua		Mid Apr.	Lower Park: CSUC Campus	Gravity		Riparian Woodland, landscaped areas, in field east of Hwy 99 on south side of creek
Northern California black walnut Juglans hindsii		April-May	Lower, Middle and Upper Park	Mammals		Riparian Woodland; no known native stands of Juglans hindsii in Butte County, widely naturalized, under consideration as invasive plant in Bidwell Park because it may significantly reduce oak regeneration
Pecan Carya illinoinensis		Spring	Lower Park	Squirrels, scrub jays		Escapee from cultivation. Often confused with black walnut
Prickly lettuce Lactuca serriola		Early April-Nov	Upper Park			Cal-IPC considers it an agricultural weed
Silver maple Acer saccharinum		Early Spring	Lower Park	Wind		Widely planted street and shade tree that volunteers along creeks and river. Native to eastern N. America.
Virginia creeper Parthenocissus quinquefolia			Lower Park, north side along creekside trail	birds
White mulberry. Morus alba		Mid Mar-Apr.	Middle and Upper Park	Birds		Along streams and roads. The plant is dioecious, female trees producing blackberry-like fruits that ripen reddish to black. Native to China. May want to eliminate female trees to prevent spread.
Plants ranked #4 on park priority list: Invasive, but too widespread to manage
Beardgrass, rabbit's foot grass Polypogon monspeliensis	L	Early Feb	Upper Park
Bermuda grass Cynodon dactylon	M C	Mid May	Lower, Middle and Upper Park	vegetatively, seed	TISI, TNC
Big heronbill Erodium botrys		Early March-June	Upper Park by Alligator Hole			Cal-IPC considers impacts to be negligible.
Bird's-foot-trefoil Lotus corniculatus		Early April-Sept	Upper Park			Cal-IPC considers it to be primarily an agricultural weed.
Birdsrape mustard Brassica rapa	L	Early Dec-June	Upper Park by Bear Hole
Bulbous bluegrass Poa Bulbosa		Early March	Upper Park by Brown's Hole
Bur clover Medicago polymorpha	L	Late Feb-June	Lower, Middle and Upper Park			Prefers some shade and is most abundant under brush and trees.
Chicory Cichorium intybus		Late May-Nov	Lower and Upper Park
Creeping bentgrass Agrostis stolonifera	L	Early June	Middle Park by Lindo Channel
Curly dock Rumex crispus	L		Lower, Middle & Upper Park	wind, water
Curlyleaf pondweed Potamogeton crispus	M	Late May	Horseshoe Lake		GISD
Cut-leaf blackberry Rubus laciniatus		Early May-Sept	Middle Park by Lindo Channel
Cutleaf geranium Geranium dissectum		Early March-June	Upper Park
Dallisgrass Paspalum dilatatum		Early May	Upper Park
Dovefoot geranium Geranium molle		Early March-April	Upper Park by Salmon Hole			Cal-IPC comment" wildland impacts negligible"
Everlasting pea Lathyrus latifolius	UC	Mid May-Oct	Upper Park-golf course, Annie's Glen
False brome Brachypodium distachyon		Late April	Upper Park by Bear Hole
Foxtail or rattail fescue Vulpia bromoides		Early March	Upper Park by Bear Hole			Cal-IPC comment: "less common than v. myuros"
Fragrant water lily Nymphaea odorata		Mid May-August	Horseshoe Lake
Hairy or winter vetch Vicia Villosa		Early March-June	Upper Park by Rod and Gun Club			Cal-IPC--"widespread but minor impacts in wildlands"
Hedgehog dogtail grass Cynosurus echinatus	M	Early May	Upper Park
Hedgeparsley Torilis arvensis	M	Late April-July	Upper Park North Rim
Honey locust Gleditsia triacanthos			Lower Park-Cedar Grove, Five Mile			Cal-IPC--"very limited distribution"
Hyssop loosestrife Lythrum hyssopifolium	L	Early May-Sept	Upper Park
Indian or yellow sweet clover Melilotus indica	E	Mid April-June	Upper Park by Bear Hole			Cal-IPC-"present in human-disturbed habitats only"
Italian ryegrass Lolium multiflorum	M	Mid Dec.	Lower, Middle and Upper Park	Wind, Mammals, Water		Annual Grassland, Riparian; dominates clay soils, one of most common grasses in park
Kentucky bluegrass Poa pratensis ssp. Pratensis	L	Mid April	Upper Park by Salmon Hole		TISI, TNC
Maritime beard grass Polypogon maritimus		Early April	Upper Park-Horseshoe Lake
Mediterranean barley Hordeum marinum	M	Late March	Upper Park by Rod and Gun Club		TISI, TNC
Obtuse filaree Erodium brachycarpum	E	Late Dec-July	Upper Park by Horseshoe Lake			Cal-IPC-"impacts are negligible, transient"
Orchard grass Dactylis glomerata	L	Mid April	Upper Park by end of Yahi Trail
Oysterplant, salsify Tragopogon porrifolius		Early April-June	Lower Park by Hwy 99
Queen Anne's lace Daucus carota	E	Late April-Oct	Lower Park		TISI, TNC	Cal-IPC-"widespread especialy on roadsides
Red gum Eucalyptus camaldulensis	L	Early Feb.	Lower, Middle and Upper Park	Wind, Mammals
Red-stemmed filaree Erodium cicutarium	L	most months	Upper Park Lot P
Ripgut brome Bromus diandrus	M	Late Feb.	Lower, Middle and Upper Park	Mammals, Wind		Annual Grassland; common grass in Bidwell Park
Rose clover Trifolium hirtum	M	Late March-June, also early fall	Upper Park
Russian thistle, tumbleweed Salsola tragus	L C *	Mid June-Nov	Middle Park-Lindo Channel		GISD
Silver hair grass Aira caryophyllea	E	Mid January	Upper Park North Rim			Cal-IPC-"widespread in grasslands, impacts negligible"
Slender wild oat Avena barbata	M	Mid Jan.	Lower, Middle and Upper Park	Mammal, Wind		Annual Grassland, openings in Woodland; common grass
Smooth catsear Hypochaeris glabra	L	Late Feb-July	Upper Park Lot R
Soft brome Bromus hordeaceus	L	Late January	Upper Park
Spiny sowthistle Sonchus asper	E	Most months	Upper Park Bear Hole			Cal-IPC-"primarily agricultural weed"
Subterranean clover Trifolium subterraneum		Early March-June	Upper Park E. end of Yahi Trail
Tangier pea Lathyrus tingitanus	UC	Early Feb-July	Upper Park by Bear Hole
Velvet Grass Holcus lanatus	M	Mid April	Upper Park		TISI, TNC
White horehound Marrubium vulgare	L	Mid April-June, Sept	Upper Park
White sweet-clover Melilotus alba		Early March-Dec	Upper Park by Rod and Gun Club		TISI, TNC
White-stemmed filaree Erodium moschatum	E	Late Feb-May	Upper Park			Cal-IPC "primarily an agricultural weed"
Wild mustard Sinapis arvensis	L	Mid Oct-May	Upper Park by Day Camp
Wild oat Avena fatua	M	Late Dec.	Lower, Middle and Upper Park	Mammals, Wind		Annual Grassland, openings in Woodland; common grass
Yellow nutsedge Cyperus esculentus	B	Mid July	Middle Park-Diversion Dam
Yellow Salsify Tragopogon dubius	E	Mid March-Oct	Upper Park			Cal-IPC "Generally a minor component of disturbed area"
Plants ranked #5 on park priority list: Non-native, but do not appear to be invasive
Bee-balm Melissa officinalis		Early June-Sept	Upper Park
Black Cherry Prunus serotina			Lower Park-Cedar Grove
Curly dock Rumex crispus	L	Mid Feb-June	Annie's Glen, Upper Park
English plantain Plantago lanceolata	L	Mid April-Oct	Upper Park
Green wattle Acacia decurrens (arabica?) (melanoxion?)	E	Early Feb.-Mar.	Lower Park; Cedar Grove	Wind		Riparian-Valley Oak Woodland, road edges-need to confirm species
Japanese zelkova Zelkova serrata			Lower and Middle Park	spread by seed		On Chico's approved Street Tree List, planted in Cedar Grove Forestry Station
London plane tree Platanus acerifolia		Late Mar.-Apr.	Lower, Middle and Upper Park	Wind and water		Widely naturalized along most valley and foothill streams. It may have a reproductive advantage over the native sycamore since it appears to be resistant to sycamore anthracnose, which causes die back of twigs and flowers in native sycamore.

Common Name
Scientific Name

Listed?

IPC

Blooming Period

Locations

Dispersal Agents

Photo
Link

Control Method

Habitats / Comments

Plants ranked #1 on park priority list: Highly invasive. Should have immediate management

Algerian ivy
Hedera canariensis

Mid-Sept

Lower and Middle Park

Vegetative, birds

Riparian, woodland, encroaching from neighboring residential properties

American pokeweed
Phytolacca americana

Early Jul-Oct.

Lower and Middle Park

Birds

Riparian; spreading rapidly in Bidwell Park, becoming a fairly common weed in the Chico Urban Area.

Barbed goatgrass
Aegilops triuncialis

Early May

Upper Park 100' east of start of Middle Trail by Lot A, Pine Trailhead, Guardian Trail by Pine Trail

wind

CDFA

Only a few infestations, should eradicate before it spreads

Bladder senna
Colutea arborescens

Late May-Jun.

Lower Park; Cedar Grove, Five Mile

human, gravity; indehiscent

Riparian, Valley Oak Woodland; Came from 1 planting in 1890s. Control attempted in past, focused eradication program started by Friends of Bidwell Park in May, 2003 with about 1M plants removed so far. People spread seeds by "popping" pods as they walk through the park.

Broomsedge bluestem
Andropogon virginicus

Early Sept.

Upper Park

GISD

Moist to wet soil along streams, on seeps, along ponds, in pastures. Native to eastern U.S., destroying park's wetlands

Edible fig
Ficus carica

Late Mar.-Apr.

Lower, Middle and Upper Park

Birds, Mammals

Riparian, very large trees near old cabin site on Ten Mile House Rd and in former deer pen

English ivy
Hedera helix

Mid-Sept.

Lower and Middle Park

Vegetative, birds

No Ivy League

Riparian, Valley Oak Woodland; mature ivy encroaching from many South Park Drive neighbors

French broom
Genista monspessulana

Late Mar.-Jul.

Middle Park by Hooker Oak Recreation Area

Gravity, Water

Riparian, Valley Oak, and Foothill Woodland; disturbed road edges;

French tamarisk
Tamarix ramoissima

Early Apr.-May

One plant in Upper Park upstream of Day Camp, Lindo Channel

Wind

TISI, TNC

Riparian; dispersed by millions of dust-like seeds

Garden (Salad) burnet
Sanguisorba minor muricata

May-August

Upstream end of Upper Park

Extensive root system, need to control to prevent spread into BCCER

Giant reed, Arundo
Arundo donax

Early Oct.

Lost Park, Lower and Middle Park, Lindo Channel

Spread by rhizomes moved during flooding

TISI, TNC

Riparian; control underway since 2000 by City of Chico; about 110 mapped sites, roots and rhizomes tenacious

Himalayan blackberry
Rubus armeniacus

Early May-June

Lower, Middle and Upper Park

Birds Mammals

TISI, TNC

Riparian-Valley Oak Woodland; can be confused with native blackberry, City of Chico uses Salt Creek Crews & goats for control

Italian plumeless thistle
Carduus pycnocephalus

Mid April-June

Guardian Trail, lower end of Yahi

wind, humans, animals

TISI, TNC

Grassland, Oak Woodland-three known populations--two on Guardian Trail by former BLM property, one on Yahi near start of trail

Japanese privet
Ligustrum japonicum

Late spring-early summer

Lost Park, Camellia Way Park, Lower, Middle & Upper Park

Birds

TISI, TNC

Riparian, Valley Oak Woodland; Widely planted horticultural shrub, 264 mapped sites in park, eradication underway at Five Mile & in Lower Park

Klamath weed, St. John's wort
Hypericum perforatum

Late April-Oct

Upper Park

Grassland, Foothill Woodland

Medusahead grass
Taeniatherum caput-medusae

Late Mar.

Lower, Middle and Upper Park

Mammals

TISI, TNC

Annual Grassland; common grass in Upper Park; can be controlled with fire and grazing; some controlled burns done by City of Chico

Northern catalpa
Catalpa speciosa

Early May

Lower and Upper Park

Riparian Woodland;

Olive
Olea europaea

Late May-Jun.

Lower and Upper Park; old grove south of golf course

Birds

Riparian, Foothill Woodland; can form very dense canopies; spreading up canyon on both sides of creek

Perennial pepperweed, tall whitetop
Lepidium latifolium

Early May-Sept.

Lower Park

Wind, Water, Animals?

TISI, TNC

Riparian; roots can exceed 20 feet in depth, small infestation removed at walnut orchard area in 2003

Periwinkle
Vinca major

Mid Jan.-Jul.

Lower, Middle and Upper Park

Vegetative

TISI, TNC

Riparian, Valley Oak Woodland; forms dense sprawling mats that smother all other understory species; displaces California Grape, Native Blackberry, Pipevine, etc.

Puncturevine
Tribulus terrestris

Early May-Oct.

Lower, Middle and Upper Park

Mammals (shoes and tires)

Disturbed road and trail margins; a painful nuisance to barefoot children, dogs, and troublesome to bicyclists

Southern catalpa
Catalpa bignonioides

Late spring-summer

Lower Park-Cedar Grove

Spanish broom
Spartium junceum

Early Mar-Jul.

Upper Park

Gravity

TISI, TNC

Riparian, Valley Oak Woodland; Common and increasingly widespread on disturbed stream edges and along Hwy 32. Eradication projects conducted over 10 years by CNPS

Tree of heaven
Ailanthus altissima

Late Apr.-May

Lost Park, Annie's Glen, Lower and Middle Park

root sprouts, wind

TISI, TNC

Riparian, Valley Oak Woodland; Increasingly common and widespread tree

Yellow starthistle
Centaurea solstitialis

Most months

Lower, Middle and Upper Park

Wind

TISI, TNC

Annual Grassland, openings in Woodland; abundant and widespread; can be controlled with fire and grazing

Plants ranked #2 on park priority list: Moderately invasive. Should provide management when possible

Black locust
Robinia pseudoacacia

Mid April-May

Lower Park, Lost Park, Annie's Glen, Upper Park by Green Gate

Gravity, water, animals?

TISI, TNC

Widely naturalized along streams on the valley floor and in the foothills; scattered in lower coniferous forest. Native to eastern U.S.

Bouncingbet
Saponaria officinalis

Late June-Oct

Upper Park

Bull thistle
Cirsium vulgare

Most months

Upper Park

Wind

Riparian areas, marshes and meadows

Bur-chervil
Anthriscus caucalis

Early March-April

Lower, Middle and Upper Park

People and other animals

Should try to control in high-use areas and along trails

Canada thistle
Cirsium arvense

Late Jul.-Sept.

Wind

GISD

Troublesome in riparian areas, need to verify that it's in the park

Cheat grass, Downy brome
Bromus tectorum

Early May

Lower, Middle and Upper Park

Mammals, Wind

TISI, TNC

Annual Grassland

Chinese hackberry
Celtis sinensis

seed

Cork or rock elm
Ulmus thomasii

Cedar Grove area

Very localized infestation--need to remove many of the smaller trees, girdling will leave areas of fire-prone dead 6-8' trees

Eastern or common hackberry
Celtis occidentalis

Lower, Middle and Upper Park

European privet
Ligustrum vulgare

Early spring-early summer

Lower and Middle Park

Birds

TISI, TNC

Italian aram
Arum italicum

Early May

Lower Park

Vegetatively

Very prevalent in One Mile area especially east of Caper Acres, difficult to eradicate

Johnsongrass
Sorghum halepense

Late May

Lower and Upper Park

Rhizomes

TISI, TNC

Moist to dry fields, orchards, lawns, roadsides, waste places. Native to Mediterranean.

Mediterranean hackberry
Celtis australis

Apr.

Lower, Middle and Upper Park

Birds

Occasional small to median tree in the Chico Area, an apparent escape from the old Bidwell Forestry Station at Cedar Grove

Milk thistle
Silybum marianum

Early March-June

Lower Park by Sycamore Pool, Upper Park by Horseshoe Lake

TISI, TNC

Should try to eradicate in high-use areas

Pennsylvania blackberry
Rubus pensilvanicus

Mid May-July

Lower, Middle and Upper Park

Pyracantha, Chinese firethorn
Pyracantha angustifolia

Late May-Jun

Lower Park

Birds

Riparian, Valley Oak Woodland

Red or foxtail brome
Bromus madritensis ssp. rubens

Early June

Lower Park

TISI, TNC

Native to Australia

Silktree, mimosa
Albizia julibrissin

summer and fall

Hooker Oak, near Lower Park walnut orchard

GISD

common Chico tree, spreads easily, seed viable for 50 years, should eradicate the few trees in the park to prevent spread

Smooth hawthorn
Crataegus laevigata

Mid Apr.

Lower Park

A number of plants have volunteered at scattered locations in Bidwell Park from experimental plantings at the old Bidwell Forestry Station (now Cedar Grove) in Lower Park

Tall fescue
Festuca arundinacea

Mid-April

Upper Park

TISI, TNC

Grassland, Foothill Woodland

Thornless (elmleaf) blackberry
Rubus ulmifolius var inermis

Early May-June

Lower Park

Birds, vegetatively

Dense growth (about 30' x 150') at picnic site #8. Mentioned in Big Chico Creek Existing Conditions Report & Joe DiTomaso's Aquatic and Riparian Weeds of the West

Tocalote, Malta starthistle
Centaurea melitensis

Late Mar.-Jul.

Upper Park

Wind, Mammals

GISD

Annual Grassland, Foothill Woodland; occasional weed; can be confused with Yellow Star Thistle; old plants can flower in the Fall and early Winter

Tumbleweed, pigweed
Amaranthus albus

Early May-Sept

Upper Park

Woolly or common mullein
Verbascum thapsus

Early Mar.-Oct.

Lower and Upper Park

Wind

TISI, TNC

Riparian and disturbed areas in Woodlands; common along road edges in the County

Plants ranked #3 on park priority list: Low to moderately invasive. Should monitor.

Almond
prunus dulcis

Mid Feb-Aprilo

Lower and Middle Park

squirrels

American elm
Ulmus americana

Spring

Lower and Middle Park

Wind

Widely planted street tree. It volunteers freely along Big Chico Creek, particularly on the University campus, but so far has not been found outside the urban area. Native to eastern U.S.

Black mustard
Brassica nigra

Upper Park

Grassland, Foothill Woodland

Brazilian pepper tree
Schinus terebinthifolius

Cedar Grove

TISI, TNC

Camphor
Cinnamomum camphora

Late spring

Lower Park

birds

CAIP, UoF

Spreads easily by seed, can create thousands of seedlings from one tree

Cherry or purple leaf plum
Prunus cerasifera

Late Feb-Apr.

Lower, Middle and Upper Park

Birds

Widely naturalized along Sacramento River and other streams from the valley floor into foothill canyons. Native to southeast Europe.

Chinese pistache
Pistacia chinensis

Late March-April

Lower, Middle and Upper Park

Birds

Very common in Lower Park; may want to eradicate female trees to prevent further spreading

Common myrtle
Myrtle communis

4th St. entrance & along Woodland

birds

Doesn't seem to spread very quickly

Cotoneaster
Cotoneaster franchet (?) pannosa (?)

Spring

Cedar Grove

Need to determine exact species

Field bindweed
Convolvuulas arvensis

Early April-Oct

Upper Park

TISI, TNC

Grassland

Golden bamboo
Phyllostachys aurea

Lower Park on S. Park Dr.

Wide-creeping rootstocks form solid stands

Small patches creeping in from adjoining residence on S. Park Dr and along path from E 8th St. entrance east of Hwy 99

Japanese honeysuckle
Lonicera japonica

Early May-June

Lower Park

TISI, TNC

Mediterranean, hoary mustard
Hirschfeldia incana

Most Months

Lower, Middle and Upper Park

Gravity, Wind

Annual Grassland, Riparian, Foothill Woodland; perennial weed of dry disturbed places

Moonwort
Lunaria annua

Mid Apr.

Lower Park: CSUC Campus

Gravity

Riparian Woodland, landscaped areas, in field east of Hwy 99 on south side of creek

Northern California black walnut
Juglans hindsii

April-May

Lower, Middle and Upper Park

Mammals

Riparian Woodland; no known native stands of Juglans hindsii in Butte County, widely naturalized, under consideration as invasive plant in Bidwell Park because it may significantly reduce oak regeneration

Pecan
Carya illinoinensis

Spring

Lower Park

Squirrels, scrub jays

Escapee from cultivation. Often confused with black walnut

Prickly lettuce
Lactuca serriola

Early April-Nov

Upper Park

Cal-IPC considers it an agricultural weed

Silver maple
Acer saccharinum

Early Spring

Lower Park

Wind

Widely planted street and shade tree that volunteers along creeks and river. Native to eastern N. America.

Virginia creeper
Parthenocissus quinquefolia

Lower Park, north side along creekside trail

birds

White mulberry.
Morus alba

Mid Mar-Apr.

Middle and Upper Park

Birds

Along streams and roads. The plant is dioecious, female trees producing blackberry-like fruits that ripen reddish to black. Native to China. May want to eliminate female trees to prevent spread.

Plants ranked #4 on park priority list: Invasive, but too widespread to manage

Beardgrass, rabbit's foot grass
Polypogon monspeliensis

Early Feb

Upper Park

Bermuda grass
Cynodon dactylon

Mid May

Lower, Middle and Upper Park

vegetatively, seed

TISI, TNC

Big heronbill
Erodium botrys

Early March-June

Upper Park by Alligator Hole

Cal-IPC considers impacts to be negligible.

Bird's-foot-trefoil
Lotus corniculatus

Early April-Sept

Upper Park

Cal-IPC considers it to be primarily an agricultural weed.

Birdsrape mustard
Brassica rapa

Early Dec-June

Upper Park by Bear Hole

Bulbous bluegrass
Poa Bulbosa

Early March

Upper Park by Brown's Hole

Bur clover
Medicago polymorpha

Late Feb-June

Lower, Middle and Upper Park

Prefers some shade and is most abundant under brush and trees.

Chicory
Cichorium intybus

Late May-Nov

Lower and Upper Park

Creeping bentgrass
Agrostis stolonifera

Early June

Middle Park by Lindo Channel

Curly dock
Rumex crispus

Lower, Middle & Upper Park

wind, water

Curlyleaf pondweed
Potamogeton crispus

Late May

Horseshoe Lake

GISD

Cut-leaf blackberry
Rubus laciniatus

Early May-Sept

Middle Park by Lindo Channel

Cutleaf geranium
Geranium dissectum

Early March-June

Upper Park

Dallisgrass
Paspalum dilatatum

Early May

Upper Park

Dovefoot geranium
Geranium molle

Early March-April

Upper Park by Salmon Hole

Cal-IPC comment" wildland impacts negligible"

Everlasting pea
Lathyrus latifolius

Mid May-Oct

Upper Park-golf course, Annie's Glen

False brome
Brachypodium distachyon

Late April

Upper Park by Bear Hole

Foxtail or rattail fescue
Vulpia bromoides

Early March

Upper Park by Bear Hole

Cal-IPC comment: "less common than v. myuros"

Fragrant water lily
Nymphaea odorata

Mid May-August

Horseshoe Lake

Hairy or winter vetch
Vicia Villosa

Early March-June

Upper Park by Rod and Gun Club

Cal-IPC--"widespread but minor impacts in wildlands"

Hedgehog dogtail grass
Cynosurus echinatus

Early May

Upper Park

Hedgeparsley
Torilis arvensis

Late April-July

Upper Park North Rim

Honey locust
Gleditsia triacanthos

Lower Park-Cedar Grove, Five Mile

Cal-IPC--"very limited distribution"

Hyssop loosestrife
Lythrum hyssopifolium

Early May-Sept

Upper Park

Indian or yellow sweet clover
Melilotus indica

Mid April-June

Upper Park by Bear Hole

Cal-IPC-"present in human-disturbed habitats only"

Italian ryegrass
Lolium multiflorum

Mid Dec.

Lower, Middle and Upper Park

Wind, Mammals, Water

Annual Grassland, Riparian; dominates clay soils, one of most common grasses in park

Kentucky bluegrass
Poa pratensis ssp. Pratensis

Mid April

Upper Park by Salmon Hole

TISI, TNC

Maritime beard grass
Polypogon maritimus

Early April

Upper Park-Horseshoe Lake

Mediterranean barley
Hordeum marinum

Late March

Upper Park by Rod and Gun Club

TISI, TNC

Obtuse filaree
Erodium brachycarpum

Late Dec-July

Upper Park by Horseshoe Lake

Cal-IPC-"impacts are negligible, transient"

Orchard grass
Dactylis glomerata

Mid April

Upper Park by end of Yahi Trail

Oysterplant, salsify
Tragopogon porrifolius

Early April-June

Lower Park by Hwy 99

Queen Anne's lace
Daucus carota

Late April-Oct

Lower Park

TISI, TNC

Cal-IPC-"widespread especialy on roadsides

Red gum
Eucalyptus camaldulensis

Early Feb.

Lower, Middle and Upper Park

Wind, Mammals

Red-stemmed filaree
Erodium cicutarium

most months

Upper Park Lot P

Ripgut brome
Bromus diandrus

Late Feb.

Lower, Middle and Upper Park

Mammals, Wind

Annual Grassland; common grass in Bidwell Park

Rose clover
Trifolium hirtum

Late March-June, also early fall

Upper Park

Russian thistle, tumbleweed
Salsola tragus

Mid June-Nov

Middle Park-Lindo Channel

GISD

Silver hair grass
Aira caryophyllea

Mid January

Upper Park North Rim

Cal-IPC-"widespread in grasslands, impacts negligible"

Slender wild oat
Avena barbata

Mid Jan.

Lower, Middle and Upper Park

Mammal, Wind

Annual Grassland, openings in Woodland; common grass

Smooth catsear
Hypochaeris glabra

Late Feb-July

Upper Park Lot R

Soft brome
Bromus hordeaceus

Late January

Upper Park

Spiny sowthistle
Sonchus asper

Most months

Upper Park Bear Hole

Cal-IPC-"primarily agricultural weed"

Subterranean clover
Trifolium subterraneum

Early March-June

Upper Park E. end of Yahi Trail

Tangier pea
Lathyrus tingitanus

Early Feb-July

Upper Park by Bear Hole

Velvet Grass
Holcus lanatus

Mid April

Upper Park

TISI, TNC

White horehound
Marrubium vulgare

Mid April-June, Sept

Upper Park

White sweet-clover
Melilotus alba

Early March-Dec

Upper Park by Rod and Gun Club

TISI, TNC

White-stemmed filaree
Erodium moschatum

Late Feb-May

Upper Park

Cal-IPC "primarily an agricultural weed"

Wild mustard
Sinapis arvensis

Mid Oct-May

Upper Park by Day Camp

Wild oat
Avena fatua

Late Dec.

Lower, Middle and Upper Park

Mammals, Wind

Annual Grassland, openings in Woodland; common grass

Yellow nutsedge
Cyperus esculentus

Mid July

Middle Park-Diversion Dam

Yellow Salsify
Tragopogon dubius

Mid March-Oct

Upper Park

Cal-IPC "Generally a minor component of disturbed area"

Plants ranked #5 on park priority list: Non-native, but do not appear to be invasive

Bee-balm
Melissa officinalis

Early June-Sept

Upper Park

Black Cherry
Prunus serotina

Lower Park-Cedar Grove

Curly dock
Rumex crispus

Mid Feb-June

Annie's Glen, Upper Park

English plantain
Plantago lanceolata

Mid April-Oct

Upper Park

Green wattle
Acacia decurrens (arabica?) (melanoxion?)

Early Feb.-Mar.

Lower Park; Cedar Grove

Wind

Riparian-Valley Oak Woodland, road edges-need to confirm species

Japanese zelkova
Zelkova serrata

Lower and Middle Park

spread by seed

On Chico's approved Street Tree List, planted in Cedar Grove Forestry Station

London plane tree
Platanus acerifolia

Late Mar.-Apr.

Lower, Middle and Upper Park

Wind and water

Widely naturalized along most valley and foothill streams. It may have a reproductive advantage over the native sycamore since it appears to be resistant to sycamore anthracnose, which causes die back of twigs and flowers in native sycamore.

IPC: California Invasive Plant Council (Cal-IPC) Status Definitions

High-severe ecological impacts on physical processes, plant and animal communities and vegetation structure. Most are widely distributed ecologically.

M: Moderate-substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities and vegetation structure. Moderate to high rates of dispersal; establishment generally dependent upon ecological disturbance.
L:

Limited-invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.

E: Evaluated but not listed--either lack sufficient information to assign rating or available information indicates that the species does not have significant impacts at the present time.
UC: Under consideration for future List update

CA: California Dept. of Food and Agriculture Noxious Weed Ratings

B: "B" List of Noxious weeds; includes species that are more' widespread, and therefore more difficult to contain; agency allows county Agricultural Commissioners to decide if local eradication or co

Potentially Invasive Plant Species In Bidwell Park

Related pages:

Ranking Key