(M)A(n)gave flower spikes, cycad cones

With their towering flower stalks, blooming agaves are a big spectacle. The fact that most of them die after flowering makes it bittersweet. You do become attached to a plant that you’ve had for a number of years, and seeing it go can be sad.

This summer we’ve had two rather prominent agaves flower: a cow horn agave (Agave bovicornuta), on the left in the photo below, and an unusual hybrid I originally got from Greg Starr (Agave shrevei var. matapensis × Agave guadalajarana), on the left in the photo:

May 31, 2023

The photo above was taken on May 31. Since then, we’ve cut off the flower stalk on Agave bovicornuta; it was leaning too far forward, and I wanted to make sure it doesn’t fall and crush everything in its path. The rosette is slowly dying, and I will remove it as soon as the temperatures drop a few degrees and working outside becomes a little more pleasant.

Dying Agave bovicornuta rosette, minus flower stalk

In the photo from May 31 above, the flowers on Agave shrevei var. matapensis × Agave guadalajarana hadn’t opened up yet. They sure have now:

Agave shrevei var. matapensis × Agave guadalajarana inflorescence on July 26, 2023

That’s not all in the agave flowering department. Our last remaining Agave parrasana is getting in on the action, too. It’s a bit surprising, considering it’s only 2 ft. × 2 ft. Our other Agave parrasana was bigger when it flowered in 2021.

Agave parrasana on July 15, 2023

Agave parrasana sends up its flower stalk in the summer or fall, waits out the winter, and then opens its flowers the following spring.

Agave parrasana on July 24, 2023

But there’s even more! Our ×Mangave ‘Night Owl’, a complex hybrid involving Agave macroacantha, Agave pablocarilloi, and a couple of Manfreda species, is pushing a flower stalk, too.

×Mangave ’Night Owl’ on June 25, 2023

I planted it in December 2020, so it’s only about three years old. That’s young to be flowering. ‘Night Owl’ is solitary, but I’m hoping there’ll be some pups after it’s done blooming. This is still one of my favorite mangaves, and I’d love to have another one in the same spot.

×Mangave ’Night Owl’ on June 26, 2023

To contrast and compare, take a look at another (completely unrelated) plant that’s flowering in our garden:

Cycas revoluta cone on June 28, 2023

Our sago palm (Cycas revoluta) is coning for the first time! It’s one of the oldest plants in our garden. We bought it from Costco right after we moved into our house, so it’s 25 years old.

I asked ChatGPT to explain how Cycas revoluta reproduces, and its response is clear, concise, and botanically correct:

Cycas revoluta, commonly known as the Sago Palm or King Sago Palm, is a cycad species native to Japan. Like other cycads, it reproduces through the production of seed cones, which are the structures involved in the formation and dispersal of seeds. Here’s an explanation of the seed cones of Cycas revoluta:

General Characteristics: Seed cones of Cycas revoluta are reproductive structures that develop on mature plants. These cones are large, cylindrical structures that consist of overlapping scales tightly packed together. The cones have a unique appearance and are often mistaken for the cones of coniferous trees, but they are not closely related to conifers. [Note by Gerhard: Cycas and conifers are both gymnosperms, i.e., their seeds are not enclosed in an ovary as they are in flowering plants.]

Male and Female Cones: Cycas revoluta is dioecious, meaning that individual plants are either male or female. Male cones and female cones are produced on separate plants. The male cones are smaller and more elongated, while the female cones are larger and more rounded.

Female Cones: The female cones are the ones directly involved in seed production. They are usually larger than male cones, growing up to 12-24 inches (30-60 cm) in length. The cones start off green and gradually turn yellowish-brown as they mature. The outer surface of the cones is covered with a layer of small, waxy, protective scales.

Reproductive Process: Inside each female cone, ovules (potential seeds) are located at the base of each scale. During pollination, which typically involves wind dispersal of pollen, pollen grains from male cones must reach the female cones for fertilization to occur. The fertilized ovules develop into seeds.

Seed Development and Dispersal: As the seeds develop within the female cone, the cone’s scales protect and enclose them. Over time, the cone begins to break apart, releasing the mature seeds. The seeds are usually bright red or orange and are about the size of a large pea.

Toxicity: It’s important to note that all parts of Cycas revoluta, including the seed cones, contain toxic compounds such as cycasin and should not be ingested by humans or animals.

Cycas revoluta cone on July 25, 2023

When the cone started to emerge in late June, I wasn’t sure whether it would be female or male. Initially, I thought it was female because of its rounded appearance. However, over time the cone began to elongate, and now it’s obvious that it’s a male. There are no female sago palms nearby, so no pollination will take place.

Cycas revoluta on July 25, 2023

It’s amusing that we had to wait 25 years to find out the sex of our sago palm, but these are very long-lived plants (up to 200 years) and everything they do is slow (including growing).

© Gerhard Bock, 2023. All rights reserved. To receive all new posts by email, please subscribe here.