Walnut Creek’s Ruth Bancroft is a national authority on drought-resistant gardening. Twice a month, she and her staff share their knowledge with readers.
When people think of an Agave, they usually picture something along the lines of the classic Century Plant, Agave americana. With its swordlike leaves, which bear stout teeth along the edges and are tipped with a sharp spine, it has an imposing presence.
But Agave is a very diverse group, and many kinds look quite different from Agave americana. One of these is the delightful species Agave striata, a modest-sized plant with heads of needlelike leaves that are roughly 2 to 3 feet in diameter. It is sometimes mistaken for a Yucca because of its resemblance to Yucca whipplei (alternatively named Hesperoyucca whipplei and sometimes called Our Lord’s Candle).
While Agave striata and Yucca whipplei look alike, the leaves of Agave striata are narrower. Yucca whipplei leaves are straight, while those of Agave striata tend to curve. Over time, Agave striata becomes a multiheaded cluster of rosettes, while Yucca whipplei usually remains single — though some forms produce offshoots and form clumps.
Yucca whipplei can range in color from gray-green to blue-green to silvery. Agave striata has a greater range of leaf hues, including green or blue-green. But Agave striata may also be tinged with pink, red or purple, especially in hot, dry conditions.
Like
other Agave species, A. striata grows for many years without flowering, then puts out a tall stalk from the center of the rosette for a final burst of flowering before it dies. The stalk, which has no side branches, rises to 6 and 8 feet. Its lower portion bears wispy threadlike bracts, which are actually miniature modified leaves. The upper part holds the tubular flowers, which can be straight or curved and are surprisingly variable in color — yellow, yellow-green or vivid emerald green, sometimes tinted with red or purple, or completely dark purple.
The pollen-bearing stamens extend well beyond the petal tips, putting the yellow pollen on prominent display. In its native northeastern Mexico, A. striata is a spring- or summer-blooming species, but our plants at the Ruth Bancroft Garden seem to obey no rules and flower at any time of the year. This fall, we have four plants in bloom, with a fifth starting to send up its flower stalk.
Agave striata makes a wonderful garden addition with its neat “spike-ball” rosettes. It may be tempting to seek out particular plants with pink or red leaves, but it is worth noting that the coloration might not persist after planting, unless grown in soil that is not too rich, with lots of sun and little water.
If you have a question for the Ruth Bancroft Garden, email info@ruthbancroftgarden.org.
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