They came north out of Mexico into the desert southwest with the Spanish, though nobody knows their actual point of origin. It’s because so many pre-Columbian cultures, including the Aztecs, utilized the great blue agave, so it had been spread all over Mesoamerica in this early cultivation. A plant so useful was highly valued as a source of fiber, living fencing, food and of course, the ancient fermented beverage called “pulque.”
Linnaeus recognized this as the quintessential species by naming it Agave americana. Few other agaves are so adaptable, and since introduction it has spread throughout much of the Southern states due to a unique tolerance of heavy soils, humidity and summer rain. Thus, it makes a fine succulent accent for gardens where conditions aren’t suited to the rest of its kin.
Years ago when succulents first grew popular, an English garden TV show featured one big potted Agave americana that they managed to insert into many different landscapes. It was planted in a large pot because it won’t stand winter temperatures below 15 degrees Fahrenheit, so they’d move it into a greenhouse or sun porch for the winter.
Agave americana is a big plant, so designers love its perennial cool blue coloring. However, a less vigorous form of the species is the yellow striped Agave americana “Variegata” and the white striped A. americana “Medio Picta.” These demonstrate its variability in size, habit and coloration but may not prove nearly as adaptable to both wet summers and frosty mornings.
A mature blue agave can produce leaves 4 to 5 feet long, spreading equally as wide. They are prone to producing “pups” around the mother plant that can develop over time into a huge colony. These pups are used to propagate new plants quickly and are an affordable local source for gardeners when transplanted from around the mother.
Oddly enough the lifespan of the agave ends with a single great flowering effort that produces a massive stalk up to 26 feet tall. Experts tell us exactly when flowering occurs is variable, too. In a warm winter climate it flowers after just 10 years, while the same species growing in cooler climates can live up to 35 years.
In the landscape they are valued for the uniformity of size and growth, which make this an ideal agave for modern gardens where it can be planted in picture perfect rows and grids. To keep the agaves looking their best in this scenario, you may decide to sever and transplant all the pups as they appear. This keeps the original plant form in its pristine state rather than the mounding result of a parent surrounded by a herd of babies.
However, in the naturalistic succulent garden, the look of a thriving agave “family” is exactly what you want. These big, bold conglomerations of succulents make powerful night-lighting subjects and valuable elements of older gardens.
As the agaves age the lower leaves may touch the soil, which can make it hard to clean out the litter that accumulates around and beneath them. The litter can get saturated and stay perennially damp in wetter climates because there’s little evaporation in the shade. Long-term moisture potentially up against the root crown and leaf bases can introduce rot into the central core of the plant. Some cooler damp climate gardeners prefer to trim up the lower leaves to allow sun to warm the soil above the root zone so it dries out and remains as clean as possible.
The best way to get started with Agave americana is to find local plants and sever the pups to transplant. These will be naturally adapted to the local climate from day one. Where no parent plants are around, buy smaller individuals in 1 gallon pots are best to test their survival over the first summer and winter in your garden. If it’s successful, wait a few years to be sure it stands up to that rare super wet or super cold season. If it survives, only then plant more.
Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com. Contact her at firstname.lastname@example.org or P.O. Box 891, Morongo Valley, CA 92256.