Agave

Every agave flowers once

Each rosette flowers only once, then dies. The name century plant overstates the wait: Agave americana grown outdoors usually blooms somewhere between its 10th and 25th year, sending up a stalk 15–30 feet tall. Across the genus it can take anywhere from 5 to 60 years, and agaves kept indoors rarely flower at all. The pups around the base carry on after the mother rosette dies, so a clump outlives any one plant.

Hardy and tender agaves

Cold tolerance varies a lot from species to species, and cold that comes with wet soil is far more dangerous than dry cold.

• Parry’s agave (A. parryi): hardy in zones 7–10, and reported to survive −20°F (−29°C) when the cold is dry. Compact blue-gray rosettes about 2 feet tall.
• Century plant (A. americana): zones 8–10, and huge, up to 6 feet tall and 10 feet across.
• Spider agave (A. bracteosa): the RHS says it can survive about 8°F (−13°C) in a sheltered, very well-drained spot.
• Foxtail agave (A. attenuata): spineless, but tender. Zones 10–12 only, and frost hurts it, especially below 28°F (−2°C).

Growing agave in the ground and in pots

In the ground, agaves want full sun and sandy, gritty soil that drains fast; poorly drained soil leads to root rot. Plant them well back from paths. Most have toothed leaf edges and a hard, sharp spine at the tip, and some have sap that irritates skin, so wear gloves when you handle them.

Where winters are too cold, grow them in pots of gritty cactus mix and bring them under cover for winter. A potted agave stays much smaller than one in the ground. Cut back on water in fall and keep it nearly dry through winter. Watch for agave snout weevil, mealybugs and scale.