I have a pretty easy garden here in Portugal, and most of the stuff growing is suited to our climate. I have a number of Agave attenuata succulents growing, and they really don’t do much, except slowly grow bigger, and are a good space filler.

Agave attenuata is better known as a Foxtail Agave (sometimes called Lion’s Tail or Swan Neck) and is an evergreen succulent perennial which produces an impressive show of silvery green leaves, up to 120cm wide. But once in its life, and only once – and maybe it could take ten years - it will produce a bloom that will grow into a massive 2m to 4.5m tall flower stalk, with blooms that arch downward, and mine is coming into bloom, already taller than me, and still growing.

Monocarpic

The Foxtail Agave is monocarpic, a term derived from Greek (mono, meaning ‘single’, and karpos, meaning ‘fruit’ or ‘grain’) and means it blooms only once before dying. In the last year of its life, it produces an enormous tall flowering stalk with pale yellow flowers, and after blooming, the main plant dies but is propagated by plentiful seeds (bulbils) along the flower stem and suckers or ‘pups’ from the base. Most agave usually use only one of these two processes to replicate itself after flowering, but this is one variety that reproduces both ways. I have already replanted some of the ‘pups’, and they are doing well, and I should be able to twist off the bulbils from the fallen stem and plant them in due course.

Some bamboos are also monocarpic, (e.g. Bambusa tuida) and flowers only once in its lifetime (usually after 50-100 years, for heaven’s sake!), and will produce a large number of fruits and then die, but this timescale varies among species. Normally, new bamboos grow up from shoots at the root (and can be a real nuisance as you can’t get rid of them once they are in your garden!), and at infrequent intervals for most species, they will start to blossom, then the flowers produce fruit.

Being monocarpic isn’t as strange as it might seem, as all annual vegetables, such as wheat or rice, and biennial plants such as carrots or radish, are monocarpic. Another is the banana, with the banana's pseudostem being monocarpic, again meaning it will die down once it has flowered and fruited. Offset shoots will take over from the pseudostem and grow speedily to reach their full height and in turn flower and fruit.

Other monocarpic plants you might know about

Sempervivum, (sometimes called Hens and Chicks), and Tillandsia (air plants), are also monocarpic, meaning that each plant can only bloom once in its lifetime. Fortunately, a Sempervivum rosette will grow for many years and produce lots of offsets (chicks) before blooming out, and the ‘chicks’ will live on.

Credits: TPN; Author: Marilyn Sheridan;

Annuals can be called monocarpic since they reproduce only once in their life cycle. Not so uncommon after all then.

But sometimes it’s the length of time they take is the amazing bit. And the reason for agave taking so long is that it is native to very dry and forbidding desert areas where water is scarce, the sun is unforgiving, and the soil is not much better, so somehow it takes its time to flower at the right time.

Should it be chopped down when it stops blooming?

Since that tall flower stem will eventually topple over when the plant is weak and finished growing, it’s possible to prevent it from landing on other garden plants and damaging them, by cutting it off with a hand saw. When removing a dead plant from the ground, take extra precautions, because the sap in many agave plants is caustic. Avoid burns and skin irritation by wearing protective gloves, long sleeves, and goggles. If you get any agave sap on your skin, wash it off immediately with warm, soapy water. In the wild, the flower stalk would eventually fall over on its own, landing a few feet from the mama, with the bulbils falling off and rooting into the soil where they fell.

Author

Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man. 

Marilyn Sheridan