Download Spanish Bayonet - Lee County Extension

Stephen H. Brown, Horticulture Agent
Kim Cooprider, Master Gardener
Lee County Extension, Fort Myers, Florida
(239) 533-7513 [email protected]
http://lee.ifas.ufl.edu/hort/GardenHome.shtml
Yucca aloifolia
Family: Agavaceae
Spanish bayonet; dagger plant; Yucca
Fort Myers, early May
Two prickly species in the “prickly zone”
DelRay Beach, early June
Synonyms (discarded names): None found
Origin: North Carolina to Florida and Texas; Bermuda; Bahamas; Yucatan Peninsula; Cuba; Jamaica;
St. Lucia; Antigua and Barbuda; Guadeloupe
U.S.D.A. Zone: 8b-12 (Minimum 15°F)
Plant Type: Perennial shrub
Growth Rate: Fast
Light Requirements: Full sun; light shade
Typical Dimensions: 8-10 ft. high and varying
width
Leaf Persistence: Evergreen
Flower Color: White often streaked with purple
Flowering Months: Anytime from January-August
Intense Blooming Days: 8
Soil Requirements: Any well-drained soil
Salt Tolerance: High
Drought Tolerance: High
Wind Tolerance: High
Nutritional Requirements: Low
Major Pests: Weevils; mealybugs; scales; thrips
Propagation: Suckers; cuttings; seeds
Human Hazards: Sharp spines at tip of leaves
Uses: Seaside plantings; specimen; border;
container; flowers
Geographic Distribution
Yucca includes approximately 40 perennial
shrubs and trees. They mostly occur in southeast
and southwest United States, Mexico, Central
America and the Caribbean. Before development and the planting of exotic species, the zone
just behind the beach was once characterized by
the presence of many species of spiny plants.
This “prickly zone” was the home of the Spanish bayonet, Yucca aloifolia. The Spanish bayonet was originally restricted to the sand dunes,
shell mounds, brackish marshes, and dry areas
of North Carolina south to Florida and west to
Texas and Mexico. Its native range also includes
the Bahamas, Bermuda and some Caribbean
islands. It has been introduced elsewhere including southern Arizona and California. It continues to spread because of cultivation.
Growth Habit
Spanish bayonet is a dense, upright, rhizomatous, evergreen shrub. It can reach a height of about 15 feet
with the width depending on the degree of clumping. It has many stout unbranched stems up to 4 inches
in diameter. Branching occurs on occasion either naturally or after a stem has been severed. The tallest
stems, especially on the clump’s perimeter, usually recline because of their own weight. When that happens, the terminal end then grows upwards. It sometimes branches terminally or laterally, and along with
rhizomatous suckers, the clump expands. If the clump remains undivided, it is a single plant.
The occasional natural branching habit occurring
12 feet above the ground
The dense upright growth of a single plant at a street
intersection
Orlando, late March
Cut stem
Terminal and lateral branching from a reclined stem
Branching induced by a severed stem
Leaves
Spanish bayonet has stiff, thick, narrowly lanceolate leaves projecting from a thick trunk. The leaves are
overlapping, 12 to 30 inches long and 1 to 2 inches wide, and grooved or curved on top. The dagger-like
leaves are simple and decurrent (without petioles). They narrow at the apex with a very sharp, small
conical brown spine about 0.20 inches long. The leaf margins have minute teeth (serrated) that are not
usually noticed except upon close inspection. The leaf veins are parallel but not visible. The leaves are
most crowded in the upper part of the stem. The youngest leaves near the growing tip stand upward and
the older bottom leaves tilt downward. The dead bottom leaves are persistent, eventually drooping
against the stem. The sharp spines at the end of leaves makes it unsuitable for landscapes frequented by
children.
The overlapping leaves are tightly squeezed together
The broken brown tips of four leaves
Leaf tip and minute serration
The upper leaves are more vertically oriented
Pine Island, Mid June
The serrated margins have a minute white fringe
Flowering and Flowers
Spanish bayonet is monoecious having unisexual flowers on the same plant. In Florida, the inflorescence
appears for two to three weeks sometime from January through July. Most flowering occurs in late
March to early June. The flowers seem to appear suddenly and disappear just as quickly. Not all stems
in the clump will flower. A clump will reliably flower once a year. The intense blooming days of individual inflorescence are approximately 8 days. However, unlike agaves, the plant or stem of the Spanish
bayonet does not die after flowering.
The inflorescence is an erect panicle with a mass of flowers covering the rachis. The conspicuous panicle appears at the top of a stem, the bottom of which is partly obscured by the upward pointing leaves.
The panicle is approximately 2 feet high and 11 inches wide. The flowers on the panicle are bell-shaped
(campanulate) and pendant. They consist of 6 spreading blunt-pointed fleshy sepals. The sepals are
white but are sometimes tinged purple. The calyx commonly measures 1.75 to 1.25 inches long and 1.5
inches wide. The pedicel is usually between 0.5 to 1.0 inches long. Hidden inside the calyx are 6 stamens and a pistil. At night the flowers are visible like torches in the dark.
16 May
19 May
Looking straight down. A bird’s eye view
25 May
Pedicels attached to a hidden rachis
Flowers detached from a rachis
Late July
The same clump in mid May of the following year
Removed sepals and exposed stamens and pistils
Pollination of yucca flowers is quite specialized as it can only be pollinated by the yucca moth (pronuba
yuccasella). The female moth collects pollen from one flower and transfers it to the stigma of another
flower. At the same time it deposits its eggs in the ovary of the flower. Moth larvae then develop in the
ovary and eventually eat some of the seeds. The association is often cited as a classic example of a coevolved obligate mutualism, involving pollination and seed predation.
Fruits
The fruit is an elliptic berry 2.5 to 3.5 inches long and is rarely produced in southern-most Florida;
probably because of the scarcity of the yucca moth. It is pendant and fleshy with three pink and broad
longitudinal margins. Spanish bayonet fruit is indehiscent, not opening at maturity along definite lines.
When mature, the exterior is black and the inside has a purplish black pulp without a central core. The
mature fruit has many rounded, flat, black seeds about 0.25 inches across. The fruit matures from summer into fall.
The pendant fleshy immature fruit
DelRay Beach, early June
Immature fruits
DelRay Beach, early June
Planting and Maintenance Guidelines
The plant is easily propagated from fresh sprouts and stem cuttings. To start a plant, simply strip the
lower 6 inches or so of the leaves from the sprouts or cuttings before placing them in the garden soil to
root. It is less commonly propagated by seeds. Safety measures should be taken while working with
Spanish bayonet. They include safety glasses, thick gloves, and moving them with a long handled fork.
Spanish bayonet is adaptable to a wide range of well-drained soils and is suitable for planting on coastal
sands and sand dunes. Give it plenty of room to grow as it will attempt to colonize an area; it can be kept
as a single stem specimen or allowed to spread as appropriate. Plant it in full sun, or light or shifting
shade. It is very wind and salt resistant and tolerates salt spray without any harm. Once established, it
needs no irrigation or fertilizer under normal conditions and will almost always look green and healthy.
The sharp spines makes it an effective block and it is sometimes grown as a living fence. Avoid planting
Spanish bayonet along paths or around doors and windows. However, it can make a good accent plant at
entryways and in borders if the tips are removed with shears. Otherwise, it can be placed where limited
passage is desired. It is strongly recommended not to plant it in yards or in landscapes where children
are often present. The spines can cause infection. It can also be surrounded by a ground cover or low
growing plants to protect the unwary from harm.
Clumps about 15 years of age or older may bloom reluctantly or not at all. If this happens, cut them
back to about 3 feet or shorter to reinvigorate them. They can also be cut back to the ground without killing them.
The start of a new living fence
Fort Myers, mid May
Diseases and Insect Pests
Several leaf spotting diseases are present on Spanish bayonet. They include Anthracnose, Coniothyrium
or brown leaf spot and Cytosporina or gray leaf spot. Avoid overhead irrigation and remove infested
leaves to control the disease.
The major arthropod pests of this plant include mealybugs, scales, thrips and weevils. The most serious
pest is agave snout weevil (Scyphophorus acupunctatus). The adult female weevil, about 1/2 in. long
and brownish, uses its "snout" to puncture the base of a plant and lay eggs. In this process, microorganisms are introduced that decompose plant tissue, usually causing the plant to wilt, collapse, and die.
White, grublike larvae develop from the eggs and feed on the decaying tissue. The grubs (which are,
incidentally, the "worm" traditionally placed in some bottles of tequila) eventually pupate and emerge as
adults, with the entire life cycle lasting 60 to 90 days.
Agave snout weevils have devastated the Spanish bayonet clump in the background
Pine Island, late May
Adult and larval form of the agave snout weevil
The mushy decaying wood favored by the larvae
Human Uses
Other than landscape uses, Spanish bayonet has had a storied relationship with humans. The tough, fibrous stems and leaves of the yucca were commonly used by the aboriginal peoples in basketry, pottery
making, and for clothing and footwear. Tea was made from the leaves and used as a diuretic. When the
Europeans arrived in the Caribbean, they found the Taino peoples using roots they called “yuca”, referring to Manihot esculenta. The newcomers used the yucca name for the two totally different plants. The
root of yucca, Spanish bayonet, is not edible. However, Mexicans have used extracts from the roots,
which contain saponaceous (soap-like) juice, for washing. Yucca was used by pioneers to make ropes
and string for hanging up and curing meats. The edibility of Spanish bayonet flower calyx varies from
plant to plant and possibly with the age of the flowers. They are succulent and crisp and can be eaten
raw or fried.
The calyx can be eaten raw or fried
Similarity between Spanish Bayonet and Spineless Yucca
In South Florida, the Spanish bayonet is often confused with spineless yucca (Y. elephantipes). Spineless
yucca is a large shrub or small tree with one to several trunks and grows to more than 20 feet tall. The
trunks are gray, rough and are leafless in taller specimens except at the very end. The base of the plant
becomes swollen with age, often clustered with suckers. The leaves are longer than those of the Spanish
bayonet and not as tightly packed. Leaf margins are smooth and leaf tips are spineless. The rachis of the
inflorescence is partially exposed. Unlike Spanish bayonet, spineless yucca does not spread by rhizomes.
Spineless yucca
Spineless yucca in light bloom Fort Myers, early June
The swollen base of Y. elephantices with its suckers
Decurrent leaves.
Left two leaves. Y. aliofolia. The far left leaf is 18” x 1.25”
Right two leaves. Y. elephantices. The leaf on the right is 28” x 2”
References
Austin, Daniel F. 2004. Florida Ethnobotany. CRC Press. Boca Raton, Florida
Austin, D., Honeychurch, P. Bass, S. 1991. Coastal Dune Plants. Gumbo Limbo Nature Center of South
Palm Beach County. Palm Beach, Florida
Dehgan, Bijan. 1998. Landscape Plants for Subtropical Climates. University Press of Florida.
Gainesville, Florida
Gilman, Edward. 2011. Yucca aloifolia Spanish Bayonet. FPS-614. UF/IFAS University of Florida,
Gainesville, Florida
Haehle, Robert and Brookwell, Joan. 2004. Native Florida Plants. Taylor Trade Publishing. Lanham,
Maryland
Knox, G.W.,. 2010. Agave and Yucca: Tough Plants for Tough Times. Publication ENH1159. UF/IFAS
North Florida Research and Education Center, Quincy, Florida
Little, E., Woodbury, R., Wadsworth, F. 1974. Trees of Puerto Rico and the Virgin Islands. USDA.
Washington, D.C.
Nelson, Gil. 2003. Florida’s Best Native Landscape Plants: 200 Readily Available Species for Homeowners and Professionals. University Press of Florida. Gainesville, Florida
Poole, R., Chase, A.R., Osborne, L.S. 1992. Yucca Production Guide. UF/IFAS Central Florida Research and Education Center, Apopka, Florida.
Schuyler, Arlene Adams. 1982. Wildflowers South Florida Natives. JMG Publishing Corp. Boca Raton,
Florida
Smith, Nathan et al. 2004. Flowering Plants of the Neotropics. Princeton University Press. Princeton,
New Jersey
Workman, Richard W. 1980. Growing Native. The Sanibel-Captiva Conservation Foundation, Inc.,
Sanibel, Florida
Useful Links
YouTube Yucca aloifolia weevils
Native Plant Fact Sheets
Hedges and Screens Fact Sheet
Annuals and Bedding Plants
Small Trees for South Florida
Flowering Trees Fact Sheets
YouTube Landscape Series
All pictures taken by Stephen Brown
This fact sheet was reviewed by Peggy Cruz, Lee County Extension; Tom Becker, FYN and Master Gardener agent, Lee County Extension; Jenny Evans, Sanibel-Captiva Conservation Foundation Nursery;
D.R. Bates, D.R. Bates Liners & Gallons, Loxahatchee, Florida; Robert Barron, Southern Native, Loxachatchee, Florida; Whitney Gray, Florida Sea Grant and Florida Fish and Wildlife Conservation Commission.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, religion, age, disability,
sex, sexual orientation, martial status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension
Service, University of Florida, IFAS, Florida A. & M.. 6/2012.