Download High Priority Invasive Plants of the Kenai Peninsula

2009
High
Priority
Invasive
Plants of
the Kenai
Peninsula
We Need You to Monitor!
Kenai Peninsula Cooperative Weed Management Area
Needs Your Help Monitoring and Controlling Invasive Weeds!
Agents of Kenai Peninsula CWMA
controlling white sweetclover on
the Resurrection River.
Weed warriors of the
Kenai Peninsula CWMA eliminating
common tansy on a street corner in
Kenai.
Photo on cover by M. Shepherd, Bugwood
To report an infestation call:
Homer Soil and Water Conservation District
(907)235-8177 ext. 5
UAF Cooperative Extension Service in Kenai
(907)262-5824
Or visit:
www.alaskainvasives.org
Materials for High Priority Invasive Plants of the Kenai Peninsula were taken directly from:
1) Shephard, M., Huette, T., Nielsen, J., and Lindmuth, C. Selected invasive plants of Alaska. Forest
Service Alaska Region R10-TP-130B.
2) Carlson, M., Heys, J., Shephard, M., and Snyder. J. Invasive Plants of Alaska. Alaska Association of
Conservation Districts.
3) bugwood.org
Important Information for Reporting
• Some species in this guide are rare and others more
common. The rare species have the verbiage “If found
report immediately”. These species, if found early, are
most likely to be eradicated from the Kenai Peninsula.
• Only report common species when they are in natural
habitats or remote areas (e.g. trails, floodplains, state
and national parks).
• When you plan to report a weed in this field guide
you will need the following information: date sighted,
observer name, phone number, weed(s) spotted,
location description, and stem count (1-5, 6-50, 51+).
• Additional information: GPS points, plant photos,
plant description (e.g. seedlings, flowers, spreading)
Canada Thistle (Cirsium arvense)
Sunflower Family
If found report immediately! 235-8177 ext. 5
• A perennial that grows to five feet tall with erect, ridged
branching stems. Leaves have sharp spines, are wavy,
oblong, alternate on stem with woolly hairs on underside.
Leaves arise directly from the stem without a distinct leaf
stalk. Flowers are purple-pink in clusters at the ends of
branches.
• Forms colonies via an extensive horizontal and vertical root
system; can eventually cover acres. Also spreads by windblown seeds. Young plants appear as basal rosettes that
bloom in late summer.
• Uncommon in the Kenai Peninsula. Can be found in fields,
pastures, forests, along roadsides, ditches, and river banks.
Produces allelopathic chemicals that suppress surrounding
vegetation.
1
Spotted Knapweed (Centaurea biebersteinii)
Sunflower Family
If found report immediately! 235-8177 ext. 5
• Biennial plant that grows up to 3 feet tall from a stout
taproot. Basal rosettes have deeply lobed gray-green
leaves. Flower heads pink-purple, consisting of ray
florets only, solitary at the end of stem branches.
Involucral bracts are topped with dark comb-like fringe
giving a spotted appearance.
• Spreads only by seed. Adapted to well-drained soils.
Responsible for millions of dollars in economic loss and
environmental damage in the western United States.
• Not known to occur in Kenai Peninsula; however, found
in Anchorage, Valdez, and numerous locations in
Southeast Alaska. Look for this plant in natural and
unnaturally disturbed areas.
2
M. Rasy, Bugwood
R. Old, Bugwood
Bird Vetch (Vicia cracca)
Pea Family
Bird Vetch (Vicia cracca)
Pea Family
If found report immediately! 235-8177 ext. 5
• Perennial which reproduces by seed and vegetatively by
underground rhizomes. Multiple, branching vine-like
stems have small tendrils and alternate, pinnatelycompound leaves with 8 to 10 leaflets. Bilaterally
symmetrical purple flowers are arranged on a one-sided
spike. Flowering occurs from spring to late fall. Seeds
contained in inch-long, brown, lance-shaped pods.
• Bird vetch aggressively climbs fencing, trees, bushes,
and other vegetation, monopolizing sunlight, space, and
moisture.
• Uncommon in the Kenai Peninsula. Look for bird vetch
in disturbed areas including roadsides, trails, and hay
fields.
3
Ornamental Jewelweed
(Impatiens glandulifera)
Balsam Family
If found report immediately! 235-8177 ext. 5
• Annual herb with thick, many-branched, hexagonally angled
stems which can grow to 10 feet. Stems smooth, multibranched, with large swollen glands at the nodes. Lower
leaves opposite, while upper leaves are whorled with three
leaves to a node. Leaves lance-shaped, 6 inches long, from a
stout petiole. Leaf margins finely, sharply serrated. Irregular
flowers one inch in length, pink-purple to white, with five petals.
• Rapidly clogs wetlands and streams. Prolific seed production
and aggressive spreader make for difficult control. Unwary
gardeners have contributed to its spread into Alaska.
• Rare in Kenai Peninsula. Thrives in lowlands, riparian zones,
and along beaches.
4
Purple Loosestrife (Lythrum salicaria)
Loosestrife Family
If found report immediately! 235-8177 ext. 5
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A perennial plant which grows 2 to 8 feet tall. Produces tall spikes of purplemagenta flowers, each with 5 to 7 “ruffled” petals and a small yellow center.
Lance-shaped leaves have smooth edges, and are usually arranged
opposite one another, in groups of 2 or 3 along the stem. As many as 40
stems arise from the base of a well-established mature plant. Stems are 4 or
5-sided in cross-section.
An aggressive wetland invader, purple loosestrife chokes waterways,
degrading wildlife habitat and fish spawning areas. Single plants can
produce millions of tiny seeds.
Purple-pink flower spikes may be confused with Alaska’s native fireweed
(Epilobium spp.) but in Alaska purple loosestrife blooms in the fall, well after
fireweed blooms have faded.
Not known to occur in the Kenai Peninsula; however, one infestation was
found and is currently being managed in Anchorage. Look for purple
loosestrife in wetlands.
5
Splitlip Hempnettle (Galeopsis bifida)
Mint Family
Report if found in natural habitat or remote area! 235-8177 ext. 5
• Annual which can grow to 4 ft tall. Flowers purple, pink,
white, or pale yellow and grow in clusters at base of leaf
stalks. Stems branched, bristly-haired, and square in
cross section. Leaves opposite on stalks, egg-shaped to
lance-shaped with large rounded teeth and pointed tips.
Leaves prominently veined and covered with bristly
hairs.
• Forms dense stands on disturbed sites, forest
edges, riparian areas, meadows, and beaches.
Numerous seeds are small and easily spread on
shoes, tires, and recreational equipment. Gardeners
quickly come to despise this plant.
6
Montana Statewide NWAEPA, Bugwood
K. Beck & J. Sebastien, Bugwood
Oxeye Daisy (Leucanthemum vulgare)
Montana Statewide NWAEPA, Bugwood
Sunflower Family
Oxeye Daisy (Leucanthemum vulgare)
Sunflower Family
Report if found in natural habitat or remote area! 235-8177 ext. 5
• A short-lived showy perennial that spreads vegetatively by
rhizomes or from seeds. Heads solitary at the ends of
branches, consisting of ray and disc flowers. Leaves
hairless to sparsely hairy, becoming progressively smaller
towards the top, spoon-like leaves on base of plant.
• Common in Kenai Peninsula. Grows in roadside ditches,
disturbed areas, beach meadows, and landscaped areas.
• Distinguished from Shasta Daisy by oxeye’s smaller flower
heads, spoon-like leaves, and large teeth on the leaf margin.
Similar Invasive: Scentless False Mayweed
(Tripleurospermum perforata), is a similar looking
species that is spreading across the Kenai Peninsula.
However, leaves are divided into numerous narrow,
thread-like, branched segments. The flowers of this
invasive lack odor, which easily distinguishes it from
Chamomile.
7
Scentless False Mayweed
Japanese Knotweed
(Polygonum cuspidatum, P. bohemica)
Buckwheat Family
If found report immediately! 235-8177 ext. 5
• An herbaceous perennial that forms extremely dense
stands, shading out native vegetation. Stems to 10 feet tall,
hollow, bamboo-like with thickened nodes where the leaf
stalks meet the stem. Reproduces from extensive spreading
rhizomes or broken-off pieces of stem. Leaves broadly oval
and up to 6 inches long. Has small white to greenish-white
flowers that bloom in late August/September. Dies back,
turning bright yellow before dropping leaves in the fall.
• Clogs waterways and lowers quality of habitat for wildlife,
fish, and invertebrates. Has displaced salmonberries along
shorelines.
• Not known to occur in the Kenai Peninsula but could likely
thrive here. Grows in Kodiak and Southeast Alaska. Found
on roadsides, stream banks, and beach meadows.
8
White Sweetclover (Melilotus alba)
Yellow Sweetclover (M. officinalis)
Pea Family
If found report immediately! 235-8177 ext. 5
• A biennial legume. In the first season of growth, sweetclover
produces vegetative shoots which may reach 12 inches. In its
second season of growth, plants can grow up to 6 feet.
Upright growth habit. Intolerant of shade. White and yellow
sweetclover are very similar, differing primarily in flower color.
Leaves toothed and compound with three leaflets.
• Growing aggressively along the Matanuska, Nenana, and
Stikine Rivers of Alaska. Sweetclover has been shown to
negatively impact native vegetation in river habitats.
• Excluding Seward, uncommon in the Kenai Peninsula. Rapidly
colonizes open waste areas and quickly spreads along riparian
areas and riverbanks.
9
Non-native Yellow Flowered Hawkweeds
Sunflower Family
Meadow Hawkweed (Hieracium caespitosum)
Mouse-ear hawkweed (H. pilosella)
Narrowleaf Hawkweed (H. umbellatum)
Common Hawkweed (H. lachenalii)
hawkweed
If found report immediately! 235-8177 ext. 5
• Both native and non-native species of yellow-flowering hawkweed
exist in Alaska. Native Alaskan hawkweeds lack stolons, have
branched stems with many leaves, and generally are found in highelevation meadows.
• Mouse-ear hawkweed has a solitary yellow flower
• Similar in appearance to orange hawkweed, meadow hawkweed
grows to 3 feet, its stem covered in coarse black gland-tipped hairs,
and bearing multiple yellow flowers.
• Narrowleaf hawkweed has hairy leaves with serrated margin.
• Common hawkweed has 7-10 stem leaves that are strongly toothed
and taper to a narrow stem.
• Uncommon in Kenai Peninsula but are found in Swanson oil field and
Kenai area. Look for these species among natural and unnatural
disturbances including roads and river floodplains.
10
Narrowleaf Hawksbeard (Crepis tectorum)
Sunflower Family
Report if found in natural habitat or remote area! 235-8177 ext. 5
• Annual or winter annual to 3 feet tall. Basal leaves are
stalked and lance-shaped with margins varying from
numerous backward-pointing teeth to deeply lobed.
Stem leaves clasp the stem. Bracts below dandelion-like
yellow ray flowers are smooth, lacking hairs. Milky juice
produced by stems when broken.
• Competes with seedlings, forage plants, cereals and
oilseeds. Spreads into riparian areas and burned lands.
• Common in the Kenai Peninsula. Often found on
disturbed soil, waste places, river floodplains, or
roadsides. Thrives in dry, coarse soils.
11
botanika.bf.jcu.cz
Fall Dandelion (Leontodon autumnalis)
T. Heutte, Bugwood
Sunflower Family
Fall Dandelion (Leontodon autumnalis)
Sunflower Family
Report if found in natural habitat or remote area! 235-8177 ext. 5
• Fall dandelion is a perennial plant that spreads from both
rhizomes and seed. Leaves are clustered at the base of
the plant and are deeply lobed. Thin stems arise directly
from the basal rosette, which can have one to many
yellow flower-heads. Plant stems have few leaves and
do not exude a milky sap when broken.
• Fall dandelion does not bloom until late in the growing
season. This species is displacing grass species in
pastures and rangeland on the Kenai Peninsula. It is
likely being transported by humans with contaminated
hay.
• Fall dandelion is common along roads and hayfields in
and around Homer and Anchor Point.
12
Perennial Sowthistle (Sonchus arvensis)
Sunflower Family
If found report immediately! 235-8177 ext. 5
• Perennial with flowers and leaves similar to common
dandelion. Plants grow 4 to 5 feet tall. Flower heads are
1 to 2 inches across. Stems are branched only at the
top. Basal and stem leaves have prickly margins.
Plants exude a milky sap when broken.
• Can drastically reduce crop yields in agricultural areas
and displace native plants on beaches and in meadows
by competing for light and nutrients.
• Rare in Kenai Peninsula. Can grow in waste areas,
gardens, meadows, woods, lawns, roadsides, beaches,
ditches, and river and lake shores
13
Common Tansy (Tanacetum vulgare)
Sunflower Family
If found report immediately! 235-8177 ext. 5
• Perennial, spreads by seed and by short rhizomes, forming
dense clumps. Flat-topped cluster of button-like yellow
flowers lacking petals. Numerous composite flower heads
(20 to 200 per plant). Leaves alternate and deeply divided
into narrow individual leaflets, giving a feathery appearance.
Plants grow to five feet tall. Strong odor.
• Mildly toxic to grazing animals. Used commonly in gardens
where it tends to spread into other yards and natural areas.
This plant can restrict the flow of water along streams.
• Excluding flower gardens, tansy is uncommon in the Kenai
Peninsula. Grows along roadsides, river and stream banks,
and beach meadows.
14
Tansy Ragwort (Senecio jacobaea)
Sunflower Family
If found report immediately! 235-8177 ext. 5
• Short-lived perennial with one to several stems arising
from a taproot. The plant grows 1 to 4 feet tall. Leaves
deeply cut. Basal leaves stalked 2 to 8 inches long.
Leaves become smaller and petioles become shorter
moving up the stem. Flower heads borne in terminal
clusters, heads consist of yellow ray and orange disc
florets. Ray florets or “petals” number 10 to 13.
• Contains a toxic compound responsible for considerable
livestock mortality. It is estimated that the state of
Oregon has lost $7 million per year to livestock
poisoning by this plant.
• Not known to occur in the Kenai Peninsula. Found in
waste places, roadsides, clear-cuts, and meadows.
15
R. Old, Bugwood
Creeping
CreepingButtercup
Buttercup(Ranunculus
(Ranunculusrepens)
repens)
Crowfoot
CrowfootFamily
Family
Creeping Buttercup (Ranunculus repens)
Crowfoot Family
Report if found in natural habitat or remote area! 235-8177 ext. 5
• Creeping buttercup is a perennial plant with stems that
grow up to 3 feet long. Basal leaves are up to 4 inches
wide, trifoliate with toothed margins. Flowering stems
are long and erect. Generally has several flowers that
are showy with 5 yellow petals. Spherical seedheads
have about 12 flattened and rounded fruits.
• Thrives in wet soils. Often found in ditches and
wetlands. Takes over yards and waste places.
• Creeping buttercup is all over Kodiak and small
populations have been reported in the Kenai Peninsula.
16
Scothbroom (Cytisus scoparius)
Pea Family
If found report immediately! 235-8177 ext. 5
• Perennial shrub to 10 feet tall from a forked taproot.
Stems strongly angled and leaves clover-like. Flowers
numerous, bright yellow, arising from the leaf bases
along the stem, similar in appearance to garden peas.
Fruits pea like, flattened, brownish-black. Reproduces
vegetatively and from seeds. Seeds remain viable for up
to 80 years.
• Grows into dense impenetrable stands which prevent
reforestation, create fire hazard, and eliminate forage for
herbivores.
• Rare in the Kenai Peninsula. Can grow along road
sides, forest edges, clearings, and meadows.
17
Common Toadflax, Butter & Eggs
(Linaria vulgaris)
Figwort Family
Report if found in natural habitat or remote area! 235-8177 ext. 5
• Similar to snapdragons. An aggressive perennial that can
reproduce by seeds or rhizomes, with 1 to 25 stems per
plant. Woody, smooth, erect, leafy, often in clumps to 2
feet tall. Numerous pale green leaves to 3 inches long,
alternate, narrow and pointed at both ends. Flowers borne
at the end of each stem in spike-like clusters, yellow, with
central bearded orange patch, one inch long, with a spur
extending below the lower lip of the corolla.
• A persistent, aggressive invader, capable of forming
dense colonies. Toxic to grazing animals.
• Common in Kenai Peninsula. Grows in natural and
unnatural habitats such as roadsides, waste areas, lake
shores, beach meadows, pastures, and edges of forests.
18
M. Shephard, Bugwood
M. Shephard, Bugwood
Orange Hawkweed (Hieracium aurantiacum)
Sunflower Family
• A perennial with colorful orange-red flowers about one
inch in diameter. Flowers consist of ray florets only with
notches upper margins. Leaves clusters in a basal
rosette. Leaves are covered in soft white hairs; stems
have shorter dark hairs. Stems 2 to 12 inches,
occasionally growing to 2 feet.
• Spreads by stolons, rhizomes, and seed. A favorite
flower of unwary gardeners and wildflower enthusiasts.
Moves into forb meadows and wetlands where it spreads
more aggressively. Forms dense mats, crowding out
native plants.
• Common in Kenai Peninsula. Found along roads, yards,
riparian areas, and beaches.
19
A. Fox, Bugwood
O. Risteski
Eurasian Watermilfoil (Myriophullum spicatum) Watermilfoil Family
Eurasian Watermilfoil (Myriophullum spicatum) Watermilfoil Family
If found report immediately! 235-8177 ext. 5
• Eurasian watermilfoil is a submersed aquatic plant, with
stems 3 feet long or more. Leaves are whorled, highly
dissected, and composed of 28-48 thread-like divisions.
Spikes emerge above the water, and flowers are borne
in the axis of bracts. Plant forms dense mats that grow
over the surface of water.
• Found in fresh to salty water of ponds, lakes, slowmowing streams, reservoirs, estuaries, and canals.
• Not known to occur in Alaska but could readily be spread
into Kenai Peninsula by float planes. This invasive alters
ecosystems and makes poor habitat for waterfowl, fish,
and other wildlife. Look for this invasive in wetlands.
20
B. Rice, Bugwood
J. Randall, Bugwood
Reed Canarygrass (Phalaris arundinacea)
Grass Family
Reed Canarygrass (Phalaris arundinacea)
Grass Family
If found in wetlands report immediately! 235-8177 ext. 5
• Tall reed-like perennial rising from stout rhizomes. Stems
are hollow, 2 to 6 feet tall, with bluish-green waxy
coating. Leaf blades flat, up to 3/4 inch wide, with
transparent ligules. Panicle inflorescence is 6 to 18 cm
long with spikelets occurring in clusters on short
scabrous branches. Seed heads compact at first then
opening at maturity.
• Forms dense, persistent, mono-specific stands that may
threaten salmon habitat. Difficult to impossible to
eradicate once established. Spreads within sties by
creeping rhizomes, effectively excluding all other
vegetation.
• Common in the Kenai Peninsula. Spreading along
several Kenai Peninsula waterways including the Kenai
River. Look for reed canary grass in human disturances
and wetlands.
21
USDA NRCS PLANTS Database, Bugwood
Smooth Cordgrass (Spartina alterniflora)
L. Lee, USC Herbarium
Grass Family
Smooth Cordgrass (Spartina alterniflora)
Grass Family
If found report immediately! 235-8177 ext. 5
• Smooth cordgrass grows 2-4 feet tall. Leaf blades are 824 inches long, tough, greenish-gray in color, and ¼ inch
wide becoming folded at tip. Plants are deciduous, and
stems die back at the end of each growing season.
Flowering part of plant is 16 inches long with 5-20 spikelike braches up to 5 inches long each.
• Found in the intertidal zone between mean high water
and mean low water.
• Not known to occur in Alaska. Still, plants may be
migrating on oceanic currents northward from British
Columbia. Forms extensive stands that convert mudflats
and channels into marsh. Conversion results in severe
impacts to waterfowl and shellfish populations.
22