This description provides characteristics that may be relevant to fire ecology
and is not meant for identification. Keys for identification are available
[38,54,58,87,91,98,136,142,145].
Banana yucca is a native, perennial shrub. It can reach heights of up to
30 feet (9.1 m) [57] and has a stem supporting a dense cluster of leaves
near the ground. Leaves are concave and rigid, supporting coarse, recurved
fibers along the margins [38,54,56,87,98]. Leaf clusters are approximately
24 to 30 inches (60-75 cm) high and twice as wide [98] with individual blades
reaching lengths of 20 to 40 inches (51-102 cm), widths of 1.25 to 1.50 inches
(3.2-3.8 cm) [136], and ending at the apex with a stiff spine 1.5 to 7.0 mm in
length [38].
Banana yucca produces both procumbent and rhizomatous stems. Procumbent stems are
always aerial and terminate in a head of leaves. The rhizomatous stems are 3.1 to
5.9 inches (8-15 cm) in diameter, 7.9 to 21.7 inches (20-55 cm) long, and covered
with thick bark. Adventitious roots sprout from the underside of the rhizomes, and 1
or 2 adventitious sprouts emerge from the upper surface. Rhizomatous stems are long-lived
and can take the form of a complex net beneath the soil surface [142].
The flowers of banana yucca are in dense panicles [143,144] found mostly among the
leaves [54]. The panicle is 12 to 36 inches (30.5-91.4 cm) long with 11 to 18 flowering
branches [136]. The fruit is large, conical, and pendulous, varying from 5.9 to
7.9 inches (15-20 cm) in length [56]. Extended water storage is achieved through
thickened leaves and leaf bases [100]. Banana yucca experiences crassulacean acid
metabolism (CAM), allowing carbohydrate stores built up in the summer and early
spring to assist during the reproductive period in late spring [85]. Computer simulations
have shown that a 3-year reproductive cycle is likely [139]. Seeds are 0.3 to 0.5
inches (8-12 mm) long and slightly ridged [98].
Fire in blackbrush habitat types where banana yucca is found can lead to undesirable
forage species such as threadleaf snakeweed inhabiting the area [19]. Prescribed burning
during fall months may protect banana yucca during reproductive periods, and burning
after rain events may increase overall survivorship. Despite the negative effect that fire
has on seeds, it is not likely to eliminate banana yucca because of its ability to resprout.
Increased amounts of Mg, Ca, K, Mn, P, and N are found underneath banana yucca after fire
and may stimulate germination of other species such as coyote tobacco (Nicotiana attenuata)
[10]. Invasive species have the potential to modify severity, frequency, and seasonality of fires.
Banana yucca provides browse to a variety of livestock in Arizona [126]. In the Mojave
Desert rangelands, domestic sheep and cattle do not utilize banana yucca as forage [60]
although cattle have been observed eating the leaves in western Texas [99]. Deer often
use banana yucca as a food source [12,55,90,122], searching out new leaves that sprout
after fire and eating from the plant at a higher frequency than when it is not burned
[72]. An analysis of various ungulate stomach contents revealed banana yucca fruit,
flowers, and stalks in mule deer and flowers and stalks in white-tailed deer [90].
Banana yucca is consumed by elk in the pinyon-juniper woodlands of Bandelier National
Monument in New Mexico [3]. Bighorn sheep browse on the leaves and fruit of banana yucca,
and various parts of the plant are also utilized by small rodents [55], birds, and
insects [12]. Although they are an insignificant part of their diet, javelina have been
spotted feeding on the fruit of banana yucca [75].
Palatability/nutritional value:
Banana yucca flower stalks are highly digestible and are an important source of
phosphorus [132]. In Arizona the stalks provide 4% of mule deer dietary needs
from May through June, adding protein, fiber, and calcium to their diets [131].
Banana yucca provides 1% to 5% of desert mule deer dietary needs during winter
months [76] while providing less than 1% of the dietary needs for Rocky Mountain
mule deer [78]. In Utah, it has moderate value as a food source for small nongame
birds [42].
Cover value:
In Utah, banana yucca provides poor cover for elk, mule deer, antelope and waterfowl.
It provides fair cover for small nongame birds and small mammals, and good cover
for upland game birds [42].
Banana yucca is the most widespread of the Yucca spp. [91]. In Arizona, it can
be found in the Great Basin conifer woodland with juniper (Juniperus spp.) and pinyon
(Pinus spp.) [22], in the interior chaparral with shrub live oak (Quercus turbinella)
[101], in semidesert grasslands with black grama (Bouteloua eriopoda) [24], and in Mojave
Desert scrub with creosotebush (Larrea tridentata) and shadscale (Atriplex confertifolia)
[128].
Banana yucca is found among the fire-adapted Arizona chaparral communities, most commonly
appearing in the shrub live oak-banana yucca-ashy silktassel (Garrya flavescens)
association with sugar sumac (Rhus ovata), desert ceanothus (Ceanothus
greggii), pointleaf manzanita (Arctostaphylos pungens), and Pringle manzanita
(A. pringlei). It is also prominent in the Arizona cypress (Cupressus arizonica)
-shrub live oak association where Emory oak (Q. emoryi), Arizona white oak (Q. arizonica),
pointleaf manzanita, and bastardsage (Eriogonum wrightii) are found [31].
On an isolated island plateau in the Grand Canyon, banana yucca was found among Colorado pinyon
(P. edulis) and Utah juniper (J. osteosperma) [62]. It occurs on the Kaibab Plateau
with Colorado pinyon, Utah juniper, blue grama (B. gracilis), and Stansbury cliffrose
(Purshia mexicana var. stansburiana) [112]. In northwestern Arizona it is found with
Utah juniper, Stansbury cliffrose, and Nevada ephedra (Ephedra nevadensis) [107], while
in the Hualapai Mountains of northeastern Arizona it is associated with singleleaf pinyon (Pinus
monophylla)-Utah juniper and interior ponderosa pine (P. ponderosa var. scopulorum)
communities [28].
Banana yucca constitutes 3.1% of canopy cover in the Dutchwoman Butte area of central Arizona.
It exists alongside redberry juniper (J. coahuilensis), catclaw acacia (Acacia greggii),
Parry's agave (Agave parryi), and tulip prickly-pear (Opuntia phaeacantha). The most
common grasses in this area include sideoats grama (B. curtipendula), hairy grama (B. hirsuta),
and plains lovegrass (Eragrostis intermedia) [4]. In this region it is also found in chaparral-type
forests dominated by shrub live oak and true mountain-mahogany (Cercocarpus montanus) [102].
In southeastern Arizona banana yucca occurs in 3 community types: Emory oak-pointleaf Manzanita-sacahuista
(Nolina microcarpa), shrub live oak-sacahuista-oneseed juniper (J. monosperma), and desert
ceanothus-birchleaf mountain-mahogany (C. betuloides)-littleleaf sumac (Rhus microphylla)
[140]. Throughout the state it can be found with stemless four-nerve daisy (Tetraneurisa caulis),
and bitterroot (Lewisia rediviva) [118]. Leaves of banana yucca have been found in fossilized
woodrat middens on Picacho Peak where the shrub no longer grows [134].
In New Mexico banana yucca can be found on a variety of landforms. It occurs on alluvial fans with
other perennials such as broom snakeweed (Gutierrezia sarothrae), tarbush (Flourensia cernua)
[139], creosotebush, soaptree yucca (Y. elata), and honey mesquite (Prosopis glandulosa) [121].
It was found on a lava flow in the Upper Sonoran zone with oneseed juniper, cactus apple (O. engelmannii),
and fourwing saltbush (Atriplex canescens) [119]. In a Chihuahuan Desert arroyo, banana yucca can be found
in limited abundance with desert willow (Chilopsis linearis), Apache plume (Fallugia paradoxa),
netleaf hackberry (Celtis reticulata), tarbush, and honey mesquite [65].
On Mt. Summerford in New Mexico, banana yucca is found on the drier south and west aspects with other
representative succulents such as Wheeler sotol (Dasylirion wheeleri), cactus apple, tulip
prickly-pear, and purple prickly-pear (O. macrocentra) [88]. Soaptree yucca and tree cholla
(O. imbricata) provide vertical structure on Otero Mesa where banana yucca is found among blue grama,
black grama, hairy grama, threeawn grasses (Aristida spp.), tobosa (Pleuraphis mutica), and
New Mexico feathergrass (Hesperostipa neomexicana) [108]. At Sandia National Laboratory it
has been found with Colorado pinyon and oneseed juniper [89].
In the Organ Mountains of New Mexico, banana yucca constituted 6% of cover in chaparral vegetation zones,
2% in savanna and woodland vegetation zones, and 1% in desert grasslands. It was found with true
mountain-mahogany, fendlerbush (Fendlera rupicola), gray oak (Q. grisea), and canyon sage
(Salvia lycioides) [41]. In southern New Mexico banana yucca co-exists with alligator juniper
(J. deppeana), interior ponderosa pine, and gray oak [43]. In the chaparral woodlands of the
Central Peloncillo Mountains of southern New Mexico, it constitutes 1% of cover [96].
In southern California, banana yucca can be found in the Tecate Peak Grove with Tecate cypress
(Cupressus forbesii), mission manzanita (Xylococcus bicolor), woolyleaf ceanothus
(Ceanothus tomentosus), and chamise (Adenostoma fasciculatum) [6]. In the Mojave Desert
region, it occurs with Cooper's goldenbush (Ericameria cooperi), white burrobrush
(Hymenoclea salsola), and desertsenna (Senna armata) [35]. In desert
shrub communities it can be found with Joshua tree (Y. brevifolia) and white burrobrush [117].
In Nevada, banana yucca is found within the high desert shrub subtype with blackbrush
(Coleogyne ramosissima), shrubby deervetch (Lotus rigidus), bladdersage
(Salazaria mexicana), and Eastern Mojave buckwheat (Eriogonum fasciculatum)
[55]. In the southern region of the state, banana yucca occurs with shrubs such as mountain big
sagebrush (Artemisia tridentata ssp. vaseyana), green ephedra (Ephedra viridis),
broom snakeweed [81], blackbrush, and Nevada ephedra [127]. It is associated with the graminoid
foxtail chess (Bromus madritensis) [20], forbs such as pincushion flower (Chaenactis
fremontii) and flatcrown buckwheat (Eriogonum deflexum) [20], and the Joshua tree
[127].
Banana yucca in southwestern Utah is commonly associated with blackbrush communities
[10,18,19,21,29,30]. It can be found with such exotics as foxtail chess [19,29,30] and cheatgrass
(B. tectorum) [29,30], and occurs on ridgetops, upper slopes, and lower slopes with
threadleaf snakeweed (G. microcephala) and broom snakeweed [21]. It is found alongside
Utah juniper [10,19], Anderson wolfberry (Lycium andersonii), and antelope bitterbrush
(Purshia tridentata) [10], and has been found with Mojave desertrue (Thamnosma
montana) and desert almond (Prunus fasciculata) in a 37-year-old burn [30].
In southwestern Colorado, banana yucca occurs in Colorado pinyon-juniper-Gambel oak
(Q. gambelii) and Gambel oak-serviceberry (Amelanchier spp.)
communities along with prickly-pear (Opuntia spp.) and milkvetch (Astragalus spp.) [123].
In Mesa Verde it associates with various plants in areas with diverse burn histories. In a
29-year-old burn area it was found with Utah serviceberry (Amelanchier utahensis),
mutton grass (Poa fendleriana), and hairy false goldenaster (Heterotheca
villosa) [45]. It occurs with antelope bitterbrush and fendlerbush in a 90-year-old
burn area, and with mutton grass and plains prickly-pear (O. polyacantha) in climax
communities [46]. Banana yucca has also been found with Fremont's goosefoot (Chenopodium
fremontii), Rocky Mountain milkvetch (Astragalus scopulorum), Johnston's
knotweed (Polygonum douglasii ssp. johnstonii), and mountain snowberry
(Symphoricarpos oreophilus) 1 year after fire, and with prickly lettuce
(Lactuca serriola), showy goldeneye (Heliomeris multiflora),
Utah serviceberry, and Gambel oak 2 years following fire [49].
In Texas, banana yucca is found with other important succulents such as lechuguilla
(Agave lechuguilla), smooth-leaf sotol (D. leiophyllum), soaptree yucca, and
Torrey's yucca (Y. torreyi) [135]. It is found on south-facing slopes in the Mount
Livermore area with Colorado pinyon, gray oak, hairy grama, and true mountain-mahogany [59].
Its range extends into western Louisiana where it can be found south of the Arkansas
River in rocky pinyon-juniper stands [144].
In Mexico, banana yucca can be found in the Madrean evergreen woodlands with rainbow
hedgehog cactus (Echinocereus rigidissimus), barrel cactus (Ferocactus
wislizenii), walkingstick cactus (O. spinosior), and tulip prickly-pear
[23]. It is of moderate importance in the Tornilla clay bed region of northern Mexico where it
occurs with creosotebush, tarbush, and lechuguilla [97], and can be found in the lower elevations
of the trans-Pecos region with creosotebush, Texas barometer bush (Leucophyllum
frutescens), lechuguilla, and Parry's agave [25].
Banana yucca occurs in the Mojave, Sonoran, and Chihuahuan desert systems. Vegetation
typical of the Mojave Desert also includes creosotebush, Joshua tree,
blackbrush, prickly-pear [141], and big galleta (Pleuraphis rigida) [36].
In the Chihuahuan Desert banana yucca occurred on 10% of 50 surveyed quadrats and
could be found with creosotebush, lechuguilla, and range ratany (Krameria parvifolia)
[116]. In the Sonoran Desert banana yucca is found in the pinyon-juniper woodlands and
in creosotebush scrub [84]
In desert plains grasslands banana yucca can be found with honey mesquite, whitethorn
acacia (Acacia constricta), catclaw acacia, and ocotillo (Fouquieria splendens)
[147]. Banana yucca is also a characteristic succulent in semidesert grasslands along with
Torrey's yucca, Thompson's yucca (Y. thompsoniana), Mojave yucca (Y. schidigera),
and Eve's needle (Y. faxoniana) [23]. It can be found on the center portion of the
bajadas with both Joshua tree and Mojave yucca [86].
A variety of insects utilize banana yucca stalks and pods, potentially benefiting the
plant by allowing seeds to be dispersed after stalks with reduced vigor fall to the
ground [94]. In New Mexico the yucca plant bug prefers banana yucca and consumes
substantial portions of photosynthesizing plant material, possibly reducing growth [50].
Banana yucca habitat in south-central New Mexico is home to black-throated sparrow
populations, containing "up to 44% of successful nests" [108]. In the Nevada
desert uplands, banana yucca is found in habitat supporting Gambel's quail [55].
In a pinyon-juniper woodland in Arizona, banana yucca production declined from 5 kg/ha
to 0 kg/ha after removal of the overstory [34]. A study conducted in New Mexico found
that banana yucca populations increased when rabbits and cattle were reintroduced after
12 years of exclusion and shrub seedlings allowed to grow following 12 years of removal
[11]. In U.S. wilderness areas banana yucca is considered resistant to trampling damage [37].
Various Native American tribes have extended histories encompassing a wide range
of uses for banana yucca. It has commonly been utilized as a food source [32]
with fruits often consumed in their raw form before fully ripening [12,33].
Cakes were often made by pit roasting the fruits [114], grinding them into
a paste, and drying the resulting material in the form of cakes [12] which could
later be traded [114] or rehydrated and made into a syrup or jelly [44]. Fermented
banana yucca has been used for beverages [67], its juices utilized as a preservative [33],
and in northern New Mexico it was used to make rum [57]. Seeds were dried and ground
up into meal, and central leaves were heated with soups or broiled with meat [12].
Banana yucca is preferred over other yuccas because of its strength [16] and many uses.
Tough fibers extracted from the leaves have been used in home building [109] and to make
products such as hair brushes, sandals, baskets, mats, fish nets, clothing, cords [12],
brooms, and soaps [91]. Banana yucca is used for ceremonial purposes and as a remedy
for vomiting and heartburn [44]. Approximately 40% of the fiber in banana yucca leaves is
extractable [142].
Banana yucca is able to reproduce vegetatively through basal bud
sprouts and rhizomes. It reproduces less frequently from seed [142].
Breeding system:
Banana yucca is monoecious [105].
Pollination:
Banana yucca is pollinated by the nocturnal pronuba moth [104]. Moths specific to banana
yucca can remain in diapause for up to 30 years, emerging only when climatic cues are
optimal for development [111]. These same moths may be responsible for the creation of
Y. baccata x Y. schidigera hybrids [80].
Seed production:
Seed production of banana yucca is plentiful [136,144]. Viable seeds
depend on sufficient, high quality pollen transfer, adequate resources for seed
development, and safe insertion of the yucca moth's ovipositor through the locular
wall so as not to damage ovules [1]. In a study conducted to determine the
effects of seed predation on banana yucca, 10% to 12% of seeds were lost to moth
larvae. The total number of viable, uneaten seeds per fruit for banana yucca was 116
with very few of them being lost to predation [70]. Tenebrionidae larvae have the
greatest effect on seedling survival, spreading bacterial and fungal infection to
seeds and inflorescence stalks [139].
Seed dispersal:
Banana yucca seeds are dispersed by vertebrates [150]. By consuming the fleshy outer
portions of the fruit, rabbits and woodrats expose the seeds for dispersal [139].
Seed banking:
No information is available on this topic.
Germination:
Germination of banana yucca seeds has been studied in laboratory settings. Borland
[15] found that with temperatures of 60° to 70 °F (16° to 21 °C), germination occurred
in as few as 7 days. While researching the effects of heat on various yuccas, Keeley
and Meyers [71] found that germination rates of banana yucca were highest when exposed to
194 °F (90 °C) temperatures for 5 minutes and plummeted to 0% when exposed for a period
of 2 hours or to temperatures of 230°F (110 °C) and greater for more than 5 minutes.
Germination was 84% when seeds were kept at room temperature.
Seedling establishment/growth:
Very few seeds of banana yucca develop into seedlings [150]. Only 9 seedlings were counted
in southern New Mexico during 4 years of observing seedling emergence [142]. Yuccas grow
slowly and utilize the same leaves for many years; this reduces the amount of energy used
in producing biomass [39].
Asexual regeneration:
Asexual reproduction of banana yucca is achieved through the propagation of basal nodules
and sprouts from rhizomes [142].
In Mesa Verde, Colorado, banana yucca was observed in 3 separate postburn environments and
occurred at the highest cover and frequency, 13% and 40% respectively, 90 years following fire.
It was observed with 6% cover and 16% frequency on a 29-year old burn and 2% cover and 14%
frequency on a 4-century-old stand [46]. Elsewhere in Colorado banana yucca has been found
1 and 2 years after fire [49].
A study of fire effects on blackbrush communities in southwestern Utah revealed populations
of banana yucca on unburned sites and sites of various time since fire. Banana yucca populations
represented 0.1% mean cover on a 1-year-old burn, 1.6% mean cover on a 12-year-old burn, and 5.5%
mean cover on a 37-year-old burn [30]. Banana yucca is distinct from other yucca species in that it
does well in partially shaded environments [15].
The currently accepted scientific name for banana yucca is Yucca baccata
Torr. (Agavaceae) [54,64,66,68,74,87,110,136,143,144]. Accepted varieties
include:
Y. b. var. baccata
Y. b. var. brevifolia (Schott ex Torr.) L. Benson & Darrow [66,136]
Y. b. var. vespertina (McKelvey) [38,58,66,67,91,98,145]
Hybrids: Banana yucca commonly hybridizes with Y. torreyi [142]. It is also known
to hybridize with Don Quixote's lace (Y. treculeana)[110], Mojave yucca (Y. Schidigera)
[58,142], and soapweed yucca (Y. glauca) [142].
Throughout this review, banana yucca will refer to all varieties of Y. baccata. A
distinction between the varieties will only be made in the distribution and occurrence
section and where information is available on site characteristics
Propagation via basal nodules and young sprouts of banana yucca has proven
successful [142] and may provide opportunities for colonizing sites where banana
yucca previously existed. Banana yucca can also be grown from seed and bare
root plantings and relocated to appropriate sites. Transplants were successfully
grown in loam and silt, potted in peat and sandy loam, and transferred to a
south-facing slope with sandy clay loam soils [122]. Banana yucca seeds are
available commercially [129].
Banana yucca plants were salvaged from the East Mojave Desert by hand digging
before mining operations. They were planted at a nursery site, and exposed roots
were dusted with sulfur powder to reduce the risk of airborne infections. Between
1 and 2 years after relocation, 71% of banana yucca were in excellent condition
(no yellowing of leaves), 15% were in poor condition, and 14% died (no green leaves
remaining) [51].
