Scientific: Agave macroacantha
Common: black spined agave
Family: Asparagaceae (subfamily Agavoideae)
Origin: Semi-tropical climates of central Mexico, Tehuacan-Cuicatlan, Oaxaca and Pueblo regions
Pronounciation: A-GA-ve ma-crow-a-CAN-tha
Hardiness zones:
Sunset 10, 12-24
USDA 9-11
Landscape Use: Black spined agave is best used in small, desert garden spaces, rock gardens, raised desert planters or containers as a color and textural accent or specimen plant.
Form & Character: Rosetting, diminuative, small, elegant, but very rigid and stiff, slowly spreading, classy, inviting, yet dangerous.
Growth Habit: Evergreen, herbaceous perennial, monocarpic, slow growth rate to 20-inches tall, densely rosetting and clumping, spreading slowly by rhizomes over time to form surprisingly extensive, densely-arranged colonies of basal offshoots (called 'ramets' or 'chupones'), several feet in diameter.
Foliage/Texture: Glaucous (blue gray), succulent, fibrous, stiff leaves about 1-inch wide to 4- to 10-inches long with prominent short and stiff marginal black spines. Leaves taper to a sharp and VERY dangerous and elongated, black spine-like tip; medium coarse texture.
A special warning: Inflatible sports balls will always meet their sudden demise and abrupt entrance into the famed Phoenix blue recycling container after intimate contact with black spined agave.
Flowers & Fruits: Towering terminal flower stalk to 6-feet tall (after 25 or more years) that produces reddish-green flowers or bulbils. It's not the most ornamental of agave flowers (so don't wait around for it to happen); fruits are brown capsules, inconspicuous to ugly (not ornamental).
Seasonal Color: None, though the vividly glacous, small, rigid and pointed leaves make for great year-around color and textural accent.
Temperature: Injured below 25oF or above 120oF. In other words, it does really well in Phoenix.
Light: Light, filtered shade from western summer sun is best, but not required.
Soil: Any soil type, but thrives best if soils are rocky and well drained or kept on the dry side.
Watering: Only limited supplemental irrigation during summer months is needed to keep plants looking healthy.
Pruning: None required.
Propagation: Division of the plentiful basal offshoots is easiest, though I wouldn't try it without using a shovel and a good pair of thick leather garden gloves. FAR, FAR less common is the rooting of bulbils or the sowing of seed.
Disease and Pests: None in Phoenix.
Additional comments: Black spined agave is truly a wonderful accent plant for those special, intimate, small desert garden spaces. It is largely care free. 'Acantha' means a sharp spiny part or structure. The leaf tips of this impressive small agave are 'macro' indeed - very sharp and dangerous!!
Plant freak alert: There are two Agave macroacantha x Agave victoria-reginae hybrids that horticultural plant freaks like myself get quite excited about. Folks, they are that special!
They are:
Some question whether these two landscape gems are different hybrids or are they the same hybrid cross? You be the judge. But to me there's no question. They are quite different based on their clumping habit, size and length of leaves, and the overall size of individual rosettes at maturity.
