Tuesday, June 23, 2020

Pretty Tall Sotols, Part 1

Love that YouTube suggested the thumbnail with bees and yellowy, clustered cheeto-shaped blooms.


How tall are sotols? They're distinctly tall. Ones that I've seen tend to be at least as tall as street lights. And they're pretty, especially with flower/flowery stalks/spikes!

Sotols have relatives that confuse the casual observers. Before I dug into sotols, I'd blogged about a yucca that some friends had suggested was a sotol. The leaves that radiate from base areas for both kinds of plants look similar. Overview websites provide introductions to sotols and similar plants, the first two also advocating sotols in xeriscaping.
Dasylirion texanum and Dasylirion wheeleri Habitat and Overall Contrast

In researching sotols, I kept encountering the scientific names Dasylirion texanum and Dasylirion wheeleri. My initial information about habitat and leaf features come from Monrovia, a plant seller.

"Texas Sotol Dasylirion texanum" states "Native to Texas Hill Country. ... Stiff, spiny, sharp-edged green leaves, to 23 [sic] feet long and 1 inches wide".

Note: After having poked around numerous sites, I'd concluded the text should have said "2-3 feet".

"Silver Desert Spoon Dasylirion wheeleri" states "Native to West Texas, Arizona, and northern Mexico. ... Spiky, fairly stiff, bluish gray leaves to 3 feet long and less than 1 inches wide".

I'm guessing these neighborhood specimens I've found are texanum because they're native to Hill Country, whereas the wheeleri WRT Texas is West Texas. Maybe if the specimens were bought and transplanted plants, they likely came from from plant sellers. Texanums would likely be cheaper and less effort to transport to Central Texas than wheeleris.

Anyway, the two Monrovia pages include images in leaf and leafhead contrasts. (I'm using "leafhead" to mean the part of the plant where the leaves grow from. The actual technical term is caudex.) Texanums' leafhead centers seem to grow from ground level, and wheeleris' leafhead centers look to radiate leaves in a spherical shape above the ground. Tiling the images side by side, the color difference stands out.

Succinct leaf descriptions come from Southern Living's "sotol": "Slender, green leaves with spiny margins form a symmetrical, rounded rosette" (Dasylirion texanum) and "Twisting, curling, ribbon-like, blue-green foliage" (Dasylirion wheeleri).

Plant Lust's "Dasylirion wheeleri" describes the twist with visuals—"the end of each leaf forms a little cowlick curl...like Elvis used to have .... If you are having trouble imagining this, think of a giant, blue-braided Afro."

More About Dasylirion texanum and Dasylirion wheeleri Foliage

From "The Genus Dasylirion Family Asparagaceae (formerly Agavaceae)":
The arching leaves (of Dasylirion texanum) may grow to four feet long. They are green to grayish green, slender and flexible with teeth along the margins. The unbranched flower spike can be fifteen feet tall. The top two to three feet of the spike is densely covered by small creamy white to yellow flowers.

Slender, three foot long, spiny, blue-gray leaves (of Dasylirion wheeleri) form a dense rosette at the top of the stem. Slender flower stalks of white flowers can grow to ten feet long or more.
A Dasylirion wheeleri characteristic that Dasylirion texanum doesn't have: "Desert Spoon, Desert Sotol, Wheeler Sotol, Grey Sotol" states "The (Dasylirion wheeleri) leaves ... are spoon-like at the base, giving the genus the common name of "desert spoon". "Dasylirion wheeleri - Spoon Yucca" succinctly describes wheeleri leaves and spoon association: "The 3 foot long narrow leaves are blue-gray color with sharp serrated margins and a spoon shaped base that gives the plant one of its common name."

From "Introduction to Dasylirions (Sotols)":
It (Dasylirion wheeleri) is immediately recognizable by its pale blue, usually somewhat twisted, flat, heavily armed, very stiff and narrow 3'-4' leaves that end in a brownish tassel. It is called a desert spoon because if the leaf if removed in its entirety the base of the leaf is spoon-shaped where it was attached to the caudex/stem. The leaves come off the caudex in a strikingly symmetrical pattern forming a perfect sphere of viciously sharp but ornamental leaves.

This species (Dasylirion texanum) is not unlike Dasylirion wheeleri but distinctly a pale green color and the leaves are not twisted. Otherwise it is a very similar plant in both shape and size, and nearly as cold tolerant. Some populations, particularly in the very dry areas, are significantly smaller than most other Dasylirions having leaves only up to 2.5'-3' long.
Specimens in My Video that I'm Mostly Certain of Species

The sotol pix and videos I recorded were in late spring and early summer of 2018, 2019, and 2020.

A, newly planted plant starting to bloom
B, two sets of bloomed plants at a business
C, plant and more recently spotted plant with heavily bloomed stalk
D, plants with focus on bloomed stalks, some sagging, loads of bees
E, plant with heavily bloomed stalk
Leafheads and closer-in looks of leaves for C, D, and E, followed by one compilation image.

A and B leafhead grouping images indicate Dasylirion texanum because of the leaves radiating from the ground. C's leafheads look spiky (sunburst-like) with mild leaf twistiness, seemingly more wheeleri than texanum. (My two-year old composite shows "Texas", but I'm not totally convinced for either texanum or wheeleri.) D's leaves seem to radiate from the ground (texanum characteristic), although the color doesn't seem bright green, like E.

My sotol content became so laden that I broke it up into two sections. Think of record side A (hit side) and side B (flip side). My flip side article "Pretty Tall Sotols, Part 2" includes info with less emphasis on physical characteristics, and additional links tor deeper digging.

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