Broad-scale Impacts of Plant Response to Fire

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More info for the terms: cyme, forb

Research conducted on milkweeds of similar growth form may also apply to showy
milkweed. Mead's milkweed (Asclepias meadii) is a closely related, rhizomatous forb that grows in
the prairie states. In a study by Bowles
and others [13], prescribed burning during the dormant season
(before May) had either positive or neutral effects on seedlings on Preserves in
Missouri, Illinois, Iowa, and Kansas. Mead's
milkweed plants on burn plots produced more cymes, as well
as more flowers per cyme, compared to plants on unburned control plots [13].


provided by Fire Effects Information System Plants

Showy milkweed is native to and widely distributed in western North America. It occurs from southern Manitoba
west to British Columbia and south to Minnesota, to northwestern Texas, and California [17,44,61,63]. Plants database
provides a distributional map of showy milkweed.

Precise distribution information is unavailable for all locations where showy
milkweed may occur.  The following lists are therefore speculative and not
exhaustive, and showy milkweed may be present in other vegetation types.

Fire Ecology

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More info for the terms: fire regime, fuel, grassland, natural, root crown, seed, severity

Fire adaptations:
There is no information in the literature regarding fire adaptations of showy milkweed;
however, showy milkweed likely regenerates from both seed and by sprouting from eeply buried rhizomes and
the root crown after fire. Prolific production of hairy, light seeds allows for wind
dispersal onto burns, with plants on adjacent unburned sites serving as seed
sources after fire. Showy milkweed seed can be stored in the soil for up to 2
years [15]. Seeds also have the ability to float and survive up to 36 months in water [16], allowing
another mechanism of travel after a burn. Further research is needed on fire
adaptations of showy milkweed.

Historically, fire has been an important natural component of the savanna and
grassland communities where showy milkweed occurs [32]. Ponderosa pine and oak
savannas typically experienced fire at less than
10-year intervals [4,23]. Across the Great Plains, fires may have occurred as frequently
as every 1 to 10 years prior to European settlement [40,47]. Frequent fires
in plains grasslands affects species composition and vegetation dynamics [47],
and may favor sprouting species such as showy milkweed.

Riparian zones within mountain and plains grasslands historically had longer
fire-return intervals than surrounding vegetation. Typically burning
during drought, riparian zones usually have heavier fuel loads and burn with
higher severity than surrounding plant communities [4,5].

The following table provides fire return intervals for plant communities and
ecosystems where showy milkweed is important. For further information, see the
FEIS review of the dominant species listed below. This list may not be inclusive
for all plant communities in which showy milkweed occurs.Find further fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".

Community or ecosystem Dominant species Fire return interval range (years)
bluestem prairie Andropogon gerardii var. gerardii-Schizachyrium scoparium 40,47]
coastal sagebrush Artemisia californica 47]
plains grasslands Bouteloua spp. 47,64]
blue grama-needle-and-thread grass-western wheatgrass Bouteloua gracilis-Hesperostipa comata-Pascopyrum smithii 47,51,64]
California steppe Festuca-Danthonia spp. 47,56]
wheatgrass plains grasslands Pascopyrum smithii <5-47+ [47,48,64]
Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47
California oakwoods Quercus spp. <35 [3]
coast live oak Quercus agrifolia 2-75 [23]
blue oak-foothills pine Quercus douglasii-P. sabiniana 3]
California black oak Quercus kelloggii 5-30 [47]

Fire Management Considerations

provided by Fire Effects Information System Plants
More info for the term: seed

With light, wind-blown seed, deep rhizomes, and early successional status,
showy milkweed has adaptations that usually promote fire survivorship and
establishment in early postfire communities [55]. However, since data on
postfire regeneration of showy milkweeds are lacking, caution is recommended
when using prescribed burning if promoting showy milkweed is a fire
management objective. Small-scale burning and postfire monitoring can help
managers determine how showy milkweed responds to prescribed burning in a given
management area.

Habitat: Cover Types

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More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: cover


63 Cottonwood

222 Black cottonwood-willow

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

246 California black oak

250 Blue oak-foothills pine

255 California coast live oak

Habitat: Ecosystem

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More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub


FRES17 Elm-ash-cottonwood

FRES21 Ponderosa pine

FRES28 Western hardwoods

FRES34 Chaparral-mountain shrub

FRES37 Mountain meadows

FRES38 Plains grasslands

FRES39 Prairie

FRES40 Desert grasslands

FRES42 Annual grasslands

Habitat: Plant Associations

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More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: forest, shrub


K010 Ponderosa shrub forest

K011 Western ponderosa forest

K030 California oakwoods

K035 Coastal sagebrush

K065 Grama-buffalo grass

K070 Sandsage-bluestem prairie

Habitat: Rangeland Cover Types

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More info on this topic.

This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the terms: cover, grassland, shrub, woodland


201 Blue oak woodland

202 Coast live oak woodland

203 Riparian woodland

204 North coastal shrub

205 Coastal sage shrub

214 Coastal prairie

215 Valley grassland

310 Needle-and-thread-blue grama

605 Sandsage prairie

607 Wheatgrass-needlegrass

608 Wheatgrass-grama-needlegrass

611 Blue grama-buffalo grass

614 Crested wheatgrass

704 Blue grama-western wheatgrass

Immediate Effect of Fire

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More info for the term: seed

The immediate effect of fire on showy milkweed is not documented; however, fire
likely top-kills showy milkweed. Soil-stored seed and rhizomes are probably insulated from
fire damage.

Importance to Livestock and Wildlife

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More info for the term: cover

Showy milkweed is toxic to most grazing animals. It possesses moderate concentrations of cardenolides (cardiac
glycosides) [42], and can poison or even kill
grazing animals [22,34].

Showy milkweed is an important host plant for monarch butterflies.
Monarch butterflies are specialist herbivores of plants
in the milkweed family (Asclepiadaceae), and sequester cardenolides to repel
predators [28].

Palatability/nutritional value:
Showy milkweed is distasteful to livestock [18,22,34].

Showy milkweed contains 16.3% crude protein, which is similar to alfalfa hay
(16%), and contains a higher concentration of essential amino acids than corn
(Zea mays) [1]. The following table is a comparison of amino acid composition of
showy milkweed residue, alfalfa (Medicago sativa), and corn [2].

Amino Acid Showy milkweed residue
(mg/g) Alfalfa
(mg/g) Corn grain
Alanine 8.9 9.9 7.9
Arginine 8.9 7.0 4.0
Aspartic acid 15.8 17.0 2.0
Cystine 0.9 3.0 1.0
Glutamic acid 15.3 12.6 27.0
Glycine 8.7 8.0 5.0
Histidine 3.7 3.0 2.0
Isoleucine 8.3 8.0 5.0
Leucine 14.4 10.0 12.0
Lysine 8.4 6.0 3.0
Methionine 1.9 1.0 2.0
Phenylaline 8.3 6.0 5.0
Proline 7.3 8.2 8.0
Serine 7.2 7.8 1.0
Threonine 6.8 7.0 3.0
Tryptophan 2.3 1.0 1.0
Tyrosine 4.2 5.0 5.0
Valine 9.6 7.0 5.0

Cover value:
Showy milkweed is rated as providing poor cover for small mammals, upland game birds, waterfowl,
and small nongame birds [18].

Key Plant Community Associations

provided by Fire Effects Information System Plants
More info for the terms: corpusculum, follicle, forb, fresh, fruit, monoecious, root crown, seed, warm-season

In the Willamette Valley of Oregon, showy milkweed grows primarily in open grasslands.
It sometimes occurs in riparian zones and savannas with small trees [27].

In plains grasslands of western Nebraska, showy milkweed is found in grama-buffalo grass (Bouteloua
spp.-Buchloe dactyloides), grama-needle-and-thread grass-western wheatgrass (Hesperostipa
comata-Pascopyrum smithii), and sandsage-bluestem (Artemisia filifolia-Andropogon/Schizachyrium
spp.) grasslands. Green needlegrass (Stipa viridula) and threadleaf sedge (Carex filifolia)
are common codominants within these grasslands [31].


SPECIES: Asclepias speciosa

Charles Weber ©California Academy of Sciences


This description provides characteristics that may be relevant to fire ecology,
and is not meant for identification. Keys for identification are available [6,12,17,22,28,30,34,38,39,44,60,61,63].

Showy milkweed is a warm-season perennial forb [17,22,29,38,61,63]. Stems are
ascending to erect and 19.7 to 47.2 inches (50.0-119.9 cm) tall [6,17,22,24,28,38,44,61,63].
Leaves are 2.4 to 7.9 inches (8-20 cm) long
and ovate-lanceolate [6,22,24,44,61]. The inflorescence is a large, showy umbelliform cymes [6,22,63]. At 0.59 to
1.10 inch (15-28 mm) wide, they are the largest of all Asclepias species
[38,61]. The fruit is a 2.4- to 4.7- inch (6-12 cm) follicle [6,17,22,24,44]. Seeds are elliptic and 0.24 to 0.35 inch (6-9 mm) long
[6,17,22,63], with hair-like tufts (see photo above).
Showy milkweed has "deep" rhizomes [10,22].




Showy milkweed reproduces both sexually and vegetatively.

Breeding system:
Showy milkweed is monoecious.
Most Asclepias spp. are self-incompatible, requiring crosses between genetically
different individuals to produce viable seeds [11,63,65].

Showy milkweed is pollinated by wind and insects. Insect pollination
is accomplished by lepidopterans and hymenopterans. These
insects remove the pollen packet, or pollinarium, when a groove in the plant's corpusculum
entraps the hairs or appendages of the insect. The arms of the pollinarium twist, facilitating
insertion of the pollinarium into the stigmatic chamber of another flower as the
pollinating insect continues foraging [9,27,63,65]. The flowers
of Asclepias spp. produce large amounts of nectar, which serves as a
germination medium for the pollen [65].

Seed production:
Stevens [54] determined that showy milkweed produces an average of 630 seeds per stem
with a weight of 0.208 ounce (5.890 g) per 1,000 seeds.

Seed dispersal:  Seeds are
dispersed when wind catches the hair-like seed tufts. [10]. Showy milkweed's
persistence along waterways [6,12,17,28,30,34,38,42,44,53,60,61]
also suggests dispersal by water [14].

Seed banking:
Seed may be stored in water or in soil, as shown in the following studies. In
a study by Bruns [14] in the Chandler Power Canal in Prosser, Washington, showy
milkweed seeds survived in fresh water for several months. Three sets of seeds
were submerged in fresh water up to 12 months to
determine viability.  Extended viability of seeds indicates the potential
of seeds trapped or carried in irrigation water as sources of potential sources
of colonization. The following table represents the percentage of seeds
that were decomposed after 3 to 12 months of submergence in fresh water, and
germination of the submerged and dry-stored seeds after the same periods [14]:

Months after test initiated 0 3 6 9 12
Percent of submerged seeds that decomposed ---- 1 2 48 48
Percent germination of submerged seeds ---- 96 90 5 45
Percent germination of dry-stored seeds 4 14 14 26 12

Chepil's [15] study suggests that showy milkweed has a short-lived soil seedbank.
In a study performed in Saskatchewan, showy milkweed seeds were tested for
longevity, periodicity of germination, and viability of seeds in cultivated soil.
One thousand seeds were mixed in a 2.5-inch
(6.4 cm) layer of sterilized
soil in the field. From 15 November to 31 March, the soil was turned with a
trowel to a 3-inch (7.6 cm) depth 2-3 times, then sown to spring wheat (Triticum aestivum) or
cereal barley (Hordeum vulgare) in alternate years.
Ninety-five percent or more of the showy milkweed seeds germinated during the 1st year, with
the greatest germination from 7 May to 31 May, though substantial
amounts of seeds germinated until 31 July. Overall, showy milkweed seed dormancy did not
exceed 2 years [15].

Seeds can germinate in soil or when submerged in water, although submergence may lower the
germination rate if the seeds remain in water over 36 months.
The longevity of showy milkweed seeds in fresh water was
tested by Comes and others [16]
in the Chandler Power Canal in Prosser, Washington. One hundred showy milkweed
seeds were collected from the field; dried; placed separately into nylon cloth
envelopes; placed in plastic screen bags; and
submerged 11.8 inches (30 cm) beneath the water surface. Comparative germination tests were
made on seeds that had been stored dry in glass bottles at room temperature

Months after test initiated


3 6 9 12 24 36 48 60


Germination of submerged seeds 13 39 38 5 7 1 0 0
Submerged seeds remaining firm 55 47 32 14 7 3 0 0
Germination of dry-stored seeds 72 70 68 69 58 65 45 71

Germination in water was at a maximum level of 55% between 3 and 12
months, and no germination occurred after 48 months. Germination of dry-stored
seeds at the 3- to 6-month period ranged from 45% to 72% [16].

Seedling establishment/growth:
During the seedling stage, showy milkweed directs most of its energy
into root development. This contributes to drought tolerance, but the
aboveground portions of showy milkweed grow "very slowly" [2].

Asexual regeneration: Showy
milkweed spreads clonally from deep rhizomes [10,22], and probably from from
sprouting from the root crown.


Showy milkweed prefers wet areas of prairie habitats and moist,
sandy soils along waterways, ditches, streambanks, floodplains, and washbottoms. 
It is common along the banks of irrigation ditches
[1]. It can become weedy in cultivated fields, roadsides, railways, "wastelands," and
fence rows [6,12,17,28,30,34,38,42,44,53,60,61].

Showy milkweed occurs at the following elevations:

Arizona 6,000-9,000 feet (1,800-2,700 m) [39]
California  0-600 feet (0-1,900 m) [28]
Colorado 3,500-7,500 feet (1,100-2,300 m) [24]
Nevada 2,200-8,500 feet (700-2,600 m) [38]
New Mexico 6,000-9,000 feet (1,800-2,700 m) [44]
Utah  2,700-8,500 feet (800-2,600 m) [61]

Showy milkweed prefers moist soil [6,12,17,28,30,34,38,42,44,53,60,61].
It grows in all soil textures [53] and tolerates alkaline soils [17].


Little research has been done addressing the successional status of showy
milkweed; however, it is considered a "weedy" species [1,17] that
occurs in early and mid-succession. It has the
ability to quickly colonize disturbed sites (Riser, personal communication [50])
in open grasslands and partially shaded habitats.


Across showy milkweed's range, flowering occurs from May to August
[10,17,22,39,44,45,63]. Follicles dry during August and September,
and seeds disperse in September and October [10].

Management considerations

provided by Fire Effects Information System Plants
Showy milkweed interferes with crops, and is an agricultural pest [1].

In a study by Whitson and Schwope [62], 8 herbicides were tested on showy
milkweed on an irrigated grass pasture near Lovell, Wyoming. The effects of
differing rates of the herbicides are provided in [62].

Other uses and values

provided by Fire Effects Information System Plants
More info for the terms: natural, seed

Showy milkweed is being investigated as a potential multipurpose crop for
chemical feedstocks. Plants in the genus Asclepias biosynthesize toxic
cardenolides, which have toxic effects on the heart, lungs, kidneys,
gastrointestinal tract, and brain of animals.  However, after exhaustive
extraction with hexane and methanol, showy milkweed residue seems to be
equivalent to alfalfa (Medicago sativa) hay in digestibility by
domestic sheep [1].

Processed showy milkweed residue is a possible source of a variety of other products.
After extraction, showy milkweed produces the following products [1]:

Product % Yield
Hexane extract 3.8
     Pigments 0.4
     Natural rubber 0.1
     Tri-terpenoids, esters and
related compounds 3.3
Methanol extract 17.5
     Sucrose 6.0
     Inositol 0.9
     Polyphenolics 1.1
Residue 79.0
     Pectin   4.0
     Fibers 5.0
     Livestock feed 70.0

Honeybees obtain nectar from milkweed flowers, and showy milkweed could be used in honeybee pastures.
The defatted seed meal can be used as an effective pesticide for
army worms [1,25,35]. More research concerning weed control needs to be done for the economical
production of showy milkweed, as well as research on agronomy, harvesting, and storage
of showy milkweed crops[1].

Showy milkweed has been used for medicines for centuries by Native American tribes
such as the northern Cheyenne of eastern Montana. The latex was used as an
antiseptic for cuts, as well for treating ringworm, corns, and calluses. Tea
made from the roots was used for treating measles, coughs, diarrhea, and
rheumatism. Native Americans also used showy milkweed for food and utility
items. The bitter sap was removed from showy milkweed by boiling, and the stems, leaves, flowers and young
fruits could then be eaten. Young stalks were eaten like asparagus. Upon
maturity, showy milkweed stems were used for rope, cord and bowstrings [17,26,34].

Showy milkweed is used in modern medicine to control heart contractions [28].

Plant Response to Fire

provided by Fire Effects Information System Plants
More info for the terms: root crown, seed

Limited information suggests that showy milkweed establishes from seed after
fire [13]. As in many prairie plants, dormant-season fire
stimulates postfire flowering [8], so it is likely that showy milkweed
established from on-site seed as well as seed blown in from off-site seed

Showy milkweed probably also sprouts from rhizomes and the root crown after fire,
although such documentation is lacking. Research is needed on the fire ecology
of showy milkweed.

Post-fire Regeneration

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More info for the terms: geophyte, ground residual colonizer, herb, initial off-site colonizer, rhizome, root crown, secondary colonizer, seed


Rhizomatous herb, rhizome in soil

Caudex/herbaceous root crown, growing points in soil

Geophyte, growing points deep in soil

Ground residual colonizer (on-site, initial community)

Initial off-site colonizer (off-site, initial community)

Secondary colonizer (on-site or off-site seed sources)

Regional Distribution in the Western United States

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More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):


1 Northern Pacific Border

2 Cascade Mountains

3 Southern Pacific Border

4 Sierra Mountains

5 Columbia Plateau

6 Upper Basin and Range

7 Lower Basin and Range

8 Northern Rocky Mountains

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

13 Rocky Mountain Piedmont

14 Great Plains

15 Black Hills Uplift

16 Upper Missouri Basin and Broken Lands

States or Provinces

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(key to state/province abbreviations)





Asclepias speciosa

provided by wikipedia EN

Asclepias speciosa, West Eugene wetlands, Oregon

Asclepias speciosa is a milky-sapped perennial plant in the dogbane family (Apocynaceae), known commonly as the showy milkweed,[1] and is found in the Western half of North America.

Habitat and range

This species is native to the western half of North America.

Growth pattern

This flowering plant is a hairy, erect perennial.

Leaves and stems

The large, pointed, elongate, simple, entire leaves are arranged oppositely on stalks.

Inflorescence and fruit

The eye-catching, hirsute, pale pink through pinkish-purple flowers occur in dense umbellate cymes. Their corollas are reflexed and the central flower parts, five hoods with prominent hooks, form a star shape. The fruit is a large, rough follicle filled with many flat oval seeds, each with silky hairs.

This species flowers from May through September.[1]


Native Americans used fiber in the stems for rope, basketry, and nets.[1] Some Native Americans believed the milky sap had medicinal qualities, however, most species of milkweed are toxic.[1]

The young leaves and seed pods can be boiled and eaten.[2]

Butterflies and moths

Asclepias speciosa is a specific monarch butterfly food and habitat plant. Additionally, phenylacetaldehyde produced by the plants attracts Synanthedon myopaeformis, the red-belted clearwing moth.[3] It is also a larval host for the dogbane tiger moth and the queen butterfly.[4]


  1. ^ a b c d Sierra Nevada Wildflowers, Karen Wiese, 2nd Ed. 2013, p. 60.
  2. ^ Lyons, C. P. (1956). Trees, Shrubs and Flowers to Know in Washington (1st ed.). Canada: J. M. Dent & Sons. p. 196.
  3. ^ Eby, Chelsea; Gardiner, Mark G.T.; Gries, Regine; Judd, Gary J.R.; Khaskin, Grigori; Gries, Gerhard (2013-04-01). "Phenylacetaldehyde attracts male and female apple clearwing moths, Synanthedon myopaeformis, to inflorescences of showy milkweed, Asclepias speciosa". Entomologia Experimentalis et Applicata. 147 (1): 82–92. doi:10.1111/eea.12045. ISSN 1570-7458.
  4. ^ The Xerces Society (2016), Gardening for Butterflies: How You Can Attract and Protect Beautiful, Beneficial Insects, Timber Press.

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Asclepias speciosa: Brief Summary

provided by wikipedia EN
 src= Asclepias speciosa, West Eugene wetlands, Oregon

Asclepias speciosa is a milky-sapped perennial plant in the dogbane family (Apocynaceae), known commonly as the showy milkweed, and is found in the Western half of North America.

Wikipedia authors and editors
visit source
partner site
wikipedia EN