Yucca periculosa

In the Tehuacán-Cuicatlán Valley of southern Mexico — one of the richest semi-desert plant communities on Earth, where columnar cacti of the genus Neobuxbaumia tower like church spires alongside giant barrel cacti (Echinocactus platyacanthus), agaves of a dozen species, and ponytail palms (Beaucarnea recurvata) — entire hillsides are crowned with dense groves of a massive tree yucca that the Aztecs called iczotl and that Mexicans today call izote. Yucca periculosa is one of the tallest yuccas in the genus — reaching up to 15 m (50 feet) in height according to Wikipedia, or 8–10 m (25–30 feet) according to field observers — a branching, colony-forming tree that covers the dry volcanic and limestone hillsides of Puebla, Oaxaca, Veracruz, Morelos, and Guerrero with what Mexican botanists call izotales: yucca forests. Despite its size, its abundance in the wild, and its deep roots in Mexican culture (its flowers are eaten as food since pre-Hispanic times), Yucca periculosa remains virtually unknown in cultivation outside Mexico. For gardeners and collectors, Yucca periculosa — a species in the genus Yucca — is the izote par excellence of southern Mexico: a monumental, ecologically dominant tree yucca that forms entire landscapes.

Quick Facts

Scientific name	Yucca periculosa Baker
Family	Asparagaceae (subfamily Agavoideae)
Origin	Southern Mexico: Veracruz, Morelos, Guerrero, Puebla, Oaxaca
Adult size	Tree-like, branching, 8–15 m tall; forms clonal colonies
Hardiness	−5 to −9 °C (23 to 15 °F) / USDA zones 8b–11 (estimated)
IUCN	Not assessed (common and widespread in native range)
Cultivation difficulty	2/5

Taxonomy and Nomenclature

Yucca periculosa was described by John Gilbert Baker in 1870 (The Gardeners’ Chronicle & Agricultural Gazette 1870: 1088). Baker (1834–1920) was the prolific British botanist at the Royal Botanic Gardens, Kew, who described hundreds of monocot species — including many yuccas — often from cultivated material sent to Kew from the Americas. The specific epithet periculosa is Latin for “dangerous” or “perilous” — presumably referring to the sharp, hard leaf tips of mature plants, which can cause painful injuries.

Classification. POWO classifies Yucca periculosa as a tree growing in the seasonally dry tropical biome, native to Mexico (Veracruz to Oaxaca). The fleshy, indehiscent fruit places it in the fleshy-fruited group (section Sarcocarpa / clade Aloifolia). The long synonymy reflects historical confusion with Yucca baccata — Baker himself later treated it as a variety of Yucca baccata before it was re-established as a distinct species.

Family and subfamily. Asparagaceae, subfamily Agavoideae (APG IV, 2016).

Synonyms (POWO)

• Yucca circinata Baker (1870) — described simultaneously, now synonymized
• Yucca baccata var. periculosa (Baker) Baker (1880)
• Yucca baccata var. circinata (Baker) Baker (1880)
• Yucca baccata f. periculosa (Baker) Voss (1895)
• Yucca baccata f. circinata (Baker) Voss (1895)
• Sarcoyucca periculosa (Baker) Linding. (1933) — placed in the segregate genus Sarcoyucca (fleshy-fruited yuccas), now abandoned

Common Names

Spanish: izote (pronounced “ee-SOH-tay”) — from the Nahuatl iczotl, the Aztec name for tree yuccas. This is one of the most important plant names in Mesoamerican ethnobotany, applied to several tree yucca species across Mexico and Central America. In the Tehuacán-Cuicatlán region, Yucca periculosa is THE izote — the dominant tree yucca of the landscape.

English: izote yucca. The scientific name “periculosa” (dangerous) has not generated a widely used English common name.

Morphological Description

Habit and Stem

Yucca periculosa is a large, branched, arborescent species — one of the tallest yuccas in the genus. Wikipedia reports up to 15 m (50 feet); field observers (janemming.com) cite 8–10 m (25–30 feet) as more typical. Old specimens branch extensively in the crown, producing multiple rosette-topped limbs. The species forms clonal colonies via underground stolons — field observers document mother plants erupting offsets that create groves of genetically identical trees. This stoloniferous habit, combined with the tree’s size, creates the izotales — dense yucca-dominated forests or woodland formations that are a characteristic landscape of the Tehuacán-Cuicatlán Valley.

Old leaves do not shed cleanly: they fold down alongside the trunk to form a skirt of dead leaves that insulates the stem from temperature extremes and desiccation — a strategy shared with Joshua trees (Yucca brevifolia) and several other tree yuccas.

Leaves

The leaves are bright green to green-teal, long, with white marginal filaments that curl into appealing patterns. Field observers describe the filaments as particularly attractive and conspicuous on mature plants. The leaf tips on mature plants are sharp and hard (hence periculosa), though juvenile plants have softer, less dangerous tips. The leaf width varies with age: older plants have longer and wider leaves than young specimens. The leaves on a typical mature specimen are approximately 60–100 cm long.

Inflorescence and Flowers

The inflorescence is erect, paniculate, bearing creamy-white flowers. Pollination is by yucca moths — the standard obligate mutualism. The inflorescence produces dense clusters of fleshy fruits.

Fruits and Seeds

The fruit is fleshy and indehiscent — confirmed by the long synonymy under Yucca baccata (the banana yucca) and by the genus name Sarcoyucca (“fleshy yucca”) to which it was once assigned. The seed pods are spindle-shaped, approximately 10–12 cm long and 4 cm in diameter, hanging in clusters. Seeds are black.

Similar Species and Frequent Confusions

Yucca gigantea Lem. (= Yucca elephantipes) — Spineless Yucca

The most widely cultivated tree yucca in the world — but a different species from a different region (Central Mexico to Central America, in more humid, tropical habitats). Yucca gigantea has spineless leaves (hence elephantipes); Yucca periculosa has sharp, dangerous leaf tips. Yucca gigantea has a thickened, elephant-foot trunk base; Yucca periculosa has a more conventional trunk. The two are geographically parapatric in eastern Mexico.

Yucca baccata Torr. — Banana Yucca

Baker originally treated Yucca periculosa as a variety of Yucca baccata. Both have fleshy fruit, but Yucca baccata is typically acaulescent or short-stemmed (not a 10–15 m tree), has blue-green rather than bright green leaves, and is distributed across the American Southwest (not southern Mexico).

Yucca filifera Chabaud — Palma China

Another large Mexican tree yucca (up to 10–15 m), but with pendulous inflorescences (vs. erect in Yucca periculosa) and a distribution centered on northeastern Mexico (Chihuahuan Desert). The two are geographically separated.

Distribution and Natural Habitat

Yucca periculosa is native to southern Mexico, in the states of Veracruz, Morelos, Guerrero, Puebla, and Oaxaca. The species is particularly abundant in the Tehuacán-Cuicatlán Valley — a UNESCO-recognized biodiversity hotspot between the states of Puebla and Oaxaca, famous for its extraordinarily rich columnar cactus flora and semi-desert succulent vegetation.

The habitat includes:

• Dry volcanic hillsides — the most common habitat near Tehuacán
• Limestone ridges — field observers confirm the species is not picky about substrate
• Semi-desert thornscrub (matorral xerófilo)
• Seasonally dry tropical forest margins

Associated species form one of the most spectacular plant communities in the Americas: Neobuxbaumia macrocephala (giant columnar cactus), Echinocactus platyacanthus (giant barrel cactus), Beaucarnea recurvata (ponytail palm), Agave salmiana, Agave stricta, Agave peacockii, Agave kerchovei, Agave marmorata, Agave titanota, Agave triangularis, various Opuntia spp., Pilosocereus spp., and Lysiloma spp. This is the Tehuacán-Cuicatlán floristic assemblage — one of the richest succulent plant communities on Earth.

The landscape pattern is distinctive: dense groves of Yucca periculosa — the izotales — dominate entire hillsides, forming a quasi-forest canopy above the lower cactus and agave scrub. These yucca forests are a defining feature of the Tehuacán Valley landscape.

Near population centers, the landscape is increasingly dominated by agriculture, but farmers and ranchers commonly leave the larger izote trees standing in their fields — a form of cultural landscape management that provides some passive conservation.

Conservation

Yucca periculosa has not been formally assessed by the IUCN, reflecting its relative abundance and wide distribution in southern Mexico. The species is common in the Tehuacán-Cuicatlán Biosphere Reserve (UNESCO World Heritage Site since 2018), which provides significant habitat protection. However, agricultural expansion, livestock grazing, and urban growth are gradually reducing habitat outside protected areas. The traditional practice of leaving izote trees in agricultural fields provides some informal conservation but does not protect against wholesale land-use change.

Ethnobotanical Significance — The Izote

The name izote (from Nahuatl iczotl) links Yucca periculosa to a pre-Hispanic tradition of plant use that predates the Spanish Conquest. In southern Mexico:

• Flowers: The creamy-white flowers of izote have been eaten since pre-Hispanic times. They are sold in public markets while very fresh and tender (before they become bitter), and are cooked with scrambled eggs or in green chili salsa. In the Los Tuxtlas region of Veracruz, roasted flowers are called chochos and served in tomachile sauce. In Coahuila, yucca flowers are traditional Lenten food.
• Fiber: The leaf fibers are used for cordage, weaving, and binding.
• Agricultural integration: Farmers leave izote trees standing in fields, providing shade, windbreak, and a food resource (flowers, fruit) while maintaining the cultural landscape.

A fascinating ecological connection: research has documented that Yucca periculosa serves as the probable host plant of Athis thysanete (Dyar), a rare endemic Castniidae (giant butterfly-moth) found in the Tehuacán-Cuicatlán Valley — adding an entomological layer to the species’ ecological significance.

Cultivation

Parameter	Value
Hardiness	−5 to −9 °C (23 to 15 °F) / USDA zones 8b–11 (estimated)
Light	Full sun
Soil	Tolerant: volcanic, limestone, sandy, rocky — not picky
Watering	Low; very drought-tolerant
Adult size	8–15 m tall; branching, colony-forming
Growth rate	Moderate
Difficulty	2/5

Light

Full sun is essential. The species grows on fully exposed hillsides in one of the sunniest regions of Mexico.

Soil and Drainage

Field observers are unanimous: Yucca periculosa is “not picky about soil type”. It grows on both volcanic and limestone substrates in the wild — an unusual edaphic flexibility for a yucca. This makes it one of the easier tree yuccas to cultivate, as it does not require the extreme substrate specialization of species like Yucca campestris (deep sand) or Yucca pallida (clay). Well-drained soil of any type is sufficient.

Watering

Less water is better. The Tehuacán Valley receives 400–600 mm of annual rainfall, concentrated in the summer months. The species is extremely drought-tolerant once established.

Cold Hardiness

Yucca periculosa is a subtropical species with limited cold tolerance. The Tehuacán Valley at 1,400–1,800 m experiences cool winters (occasional light frost) but not severe cold. USDA zone 8b–9a is a reasonable estimate. A field-grown specimen at the Huntington Botanical Gardens in California (zone 10a) is reported to have established well over five years. The dead-leaf skirt on the trunk provides some frost insulation for established trees.

Growth Rate and Space

Moderate. At 8–15 m tall with branching crown and clonal colonization via stolons, a mature Yucca periculosa requires enormous space. This is a landscape tree, not a garden plant — suitable for large properties, botanical gardens, parks, and ranch-scale xeriscapes.

Propagation

By seed, offsets (from stolons), and stem cuttings. The stoloniferous habit provides an efficient vegetative propagation pathway. Seeds from the fleshy fruit should be cleaned of pulp and sown in well-drained mix at 20–25 °C.

What to Know Before Buying

Availability. Yucca periculosa is “not widely grown in xeric garden landscapes across the world” despite its abundance in the wild — a paradox noted by field observers. The Huntington Botanical Gardens Succulent Symposium in California has offered it. Specialist Mexican succulent growers and some American xeric plant nurseries may have stock. The species is virtually absent from European horticulture.

Danger. The name means “dangerous” — and mature plants earn it. The leaf tips on old specimens are sharp and hard enough to cause serious puncture wounds. Plant away from paths, play areas, and high-traffic zones.

Size. At 8–15 m, this is one of the largest yuccas that can be grown. It forms clonal groves via stolons. Plan for a monumental specimen, not a border plant.

Pests and Diseases

Agave snout weevil (Scyphophorus acupunctatus): Southern Mexico is the weevil’s core range. The thick trunk and large size of Yucca periculosa make it a potential target. Monitor for frass and stem softening.

Castniidae moths: The giant butterfly-moth Athis thysanete uses Yucca periculosa as a probable host plant in the Tehuacán Valley — a fascinating ecological association rather than a significant pest problem.

Root rot: In heavy, waterlogged soils. The species’ edaphic flexibility means it tolerates a range of substrates, but standing water is still fatal.

Landscape Use

Monumental specimen tree: A mature Yucca periculosa — 8–15 m tall, multi-branched, with skirts of dead leaves and groves of clonal offspring — is one of the most imposing yuccas on Earth. In subtropical gardens, it creates the izotal landscape of southern Mexico.

Tehuacán-Cuicatlán theme gardens: The ultimate use. Plant alongside Neobuxbaumia spp., Echinocactus platyacanthus, Beaucarnea recurvata, Agave salmiana, Agave titanota, and Opuntia spp. to recreate one of the world’s most spectacular semi-desert landscapes.

Edible landscape: The flowers are eaten in Mexican cuisine — scrambled with eggs, in green salsa, or as chochos in tomachile. A mature izote in a garden provides an annual harvest of edible flowers for the adventurous cook.

Frequently Asked Questions

What does “periculosa” mean?

Latin for “dangerous” or “perilous” — referring to the sharp, hard leaf tips on mature plants, which can cause puncture wounds.

What is an “izotal”?

A yucca forest or woodland dominated by Yucca periculosa. In the Tehuacán-Cuicatlán Valley of Puebla and Oaxaca, entire hillsides are covered by izotales — dense groves of tree yuccas forming a quasi-forest canopy above the cactus and agave scrub below. This is a distinctive vegetation formation of southern Mexico.

Can I eat the flowers?

Yes. Izote flowers have been eaten in Mexico since pre-Hispanic times. They are sold fresh in markets and prepared in various ways: with scrambled eggs, in green chili salsa, or roasted in tomachile sauce. Harvest while very fresh and tender — older flowers become bitter.

How big does it get?

Up to 8–15 m (25–50 feet) tall, branching in the crown, and forming clonal colonies via stolons. This is one of the largest yuccas in the genus — a genuine tree, not a shrub or rosette plant.

Can I grow it outside Mexico?

Yes, in subtropical and Mediterranean climates (USDA zone 8b or warmer). The Huntington Botanical Gardens in California have grown it successfully. The species’ soil flexibility and drought tolerance make it relatively easy to cultivate — but it needs warmth and space.

Reference Databases and Online Resources

• POWO — Yucca periculosa
• iNaturalist — Yucca periculosa
• GBIF — Yucca periculosa
• Janemming.com — Mexico’s little-known Yucca periculosa (field observations)

Bibliography

• Baker, J.G. (1870). Yucca periculosa. The Gardeners’ Chronicle & Agricultural Gazette 1870: 1088.
• Baker, J.G. (1880). Yucca baccata var. periculosa. Journal of the Linnean Society, Botany 18: 229.
• Lindinger, K.H.L. (1933). Sarcoyucca periculosa. Beihefte zum Botanischen Centralblatt 50(1): 446.
• Eggli, U. (ed.) (2001). Illustrated Handbook of Succulent Plants: Monocotyledons. Springer-Verlag.
• Espejo Serna, A. & López-Ferrari, A.R. (1993). Las Monocotiledóneas Mexicanas: una Sinopsis Florística 1(1): 1–76. Consejo Nacional de la Flora de México.
• Albano, P.-O. (2003). La Connaissance des Plantes Exotiques. Édisud, Aix-en-Provence.
• McKelvey, S.D. (1938–1947). Yuccas of the Southwestern United States. 2 volumes. Arnold Arboretum, Harvard University.
• Molon, G. (1914). Le Yucche. Ulrico Hoepli Editore, Milano. 247 pp.