If you’re able to visit during this years spring open house, it will be hard to miss the look of love in the air. We have a record 20 century plants in spike in the garden…a number far surpassing any flowering record we’ve set previously.
Agaves are a genus of mostly monocarpic plants…they live their entire lives to flower once, then after experiencing a giant-sized orgasm, they fall over dead. In the wild, many species take up to 100 years to flower, which is why the name century plant stuck as a common name. In our more rainy climate, our century plants typically flower in 12-15 years. Several of our current crop are actually less than a decade old, but their enormous size has already been achieved, so they’re ready to reproduce.
Some species of agaves offset, and in this case, only then central rosette dies, and the offsets continue as is the case with bromeliads. Those agave species which never offset are one-and-dones, but hopefully will leave behind a plethora of seed for the next generation. From the start of the spikes to full flower is usually about 8 weeks. Below are a few of our babies in spike.
One of our favorite winter hardy (Zone 7b) century plants is the non-spiny Agave bracteosa ‘Stingray’. Here is one of our garden specimens this week, which has been thriving in the ground since 2016. Unlike most agaves, which prefer full sun, Agave bracteosa is better in part sun (full sun for only a few hours during the day). Agave bracteosa ‘Stingray’ is also a fairly slow grower that only produces a few offsets. A mature rosette will top out around 15-18″ tall x 2′ wide. We love the unique texture, which differs from all other agaves.
Since we are limited in the number of hardy century plant species, our only option for more agave diversity in the garden is to create it by crossing existing hardy species together. Here are a few of our recent successes.
Agave x amourifolia is a Plant Delights/JLBG creation from a cross we made in 2016 that combined the genes of three century plants, Agave ovatifolia, Agave lophantha, and Agave x pseudoferox ‘Logan Calhoun’. Our size estimates were that the offspring would mature at 3′ tall x 5′ wide. Here is one of our garden specimens photographed this week, which has already reached 2′ tall x 3′ wide.
Below is Agave x ovox, a 2017 cross of the two giants, Agave ovatifolia and Agave x pseudoferox ‘Bellville’. We expect this to get huge…perhaps 5′ tall x 10′ wide.
Below is Agave x protifolia is a 2016 Mike Papay cross of Agave x protamericana x Agave ovatifolia. We also expect this to get quite massive.
Below is Agave x ovatispina ‘Blue Arrows’, a 2016 Mike Papay cross of Agave ovatifolia x Agave flexispina. We would have expected this to be a mature size, but it’s achieved this in only 5 years, so we think we’re seeing some serious hybrid vigor.
Below is Agave x ocareginae, our 2016 cross of Agave ovatifolia x Agave victoriae-reginae. Most likely, this elegant small grower will never offset.
Below is Agave x schuphantha, a 2015 Mike Papay cross involving three century plant species, Agave schidigera, Agave lophantha, and Agave lechuguilla. It’s formed a beautiful, symmentrical rosette, which should be getting close to mature size.
As a plant breeder, one of the cool things we get to do is observe the diversity that arises from a single cross. In some cases, the diversity shows up in the first generation (F1), while in other cases, the first set of offspring need to have sex with each other for the diversity in the offspring to reveal itself (Mendelian genetics). Fortunately, with agaves, we can see quite a bit of diversity in the F1 populations.
Below is a cross we call Agave x amourifolia, which is our cross of Agave ovatifolia, pseudoferox (salmiana var. ferox of Hort.), and lophantha. Here are three of our selected seedlings from that cross.
Plant #1 below is showing the large size of Agave x pseudoferox and the color of Agave ovatifolia (blue), with little visible influence of the narrow leaf, yellow-centered Agave lophantha.
Plant #2 below show more color influence from Agave x pseudoferox, but with the compact form influence of Agave ovatifolia.
Plant #3 below shows equal parts Agave x pseudoferox and ovatifolia, but also, what appears some leaf narrowing we would expect from Agave lophantha.
Below is Agave x flexiferox, created from a cross of the small Agave flexispina x the giant pseudoferox (salmiana var. ferox (Hort.). Plant #1 shows the small size of Agave flexispina, with the greenish coloration of Agave x pseudoferox.
Below, Agave x flexiferox ‘Megalodon’ shows the larger size and overall coloration from Agave x pseudoferox, with some added blue tones from Agave flexispina.
Below is Agave x victoferox, a cross of Agave victoriae-reginae x pseudoferox. Plant #1 below shows the form and size of Agave victoriae-reginae with the color of Agave x psedoferox.
Hybrid #2 below shows the teeth from Agave x psedoferox (victoriae-reginae has no teeth), and a size intermediate between the two parents.
Hybrid #3 below shows a larger size and more teeth due to more genes from Agave x pseudoferox. The teeth are much smaller because of the Agave victoriae-reginae genes. The splendid compact form also comes from the Agave x victoriae-reginae parent. This cross almost resembles the Northern Mexican Agave montana.
We hope this gives you a small peek into the world of plant breeding and the subsequent evaluation and selection process.
This summer, two of our spiking clumps of Agave ovatifolia became dislodged from the ground during a violent thunderstorm. We wondered if they would still set viable seed despite being without roots, since the energy built up from 15 years of growth was still in the foliage. We made several crosses without having to set up a ladder and it appears that we’ve got good seed set. Nature is amazingly in its desire to survive.
Agave x striphantha ‘Striptease’ is a JLBG creation from a 2013 cross of Agave striata and Agave lophantha. Both parents are 30 year survivors here in the garden, so we wanted to see what a combination of genes looked like. Also, Agave striata is the only hardy agave species, whose main crown doesn’t die after flowering. So far, this gem is 3′ wide, and like the Agave striata parent, it offsets from the crown and doesn’t sucker like Agave lophantha. It’s looking like a flower spike may be imminent, so perhaps we’ll have our flowering question answered soon.
One of our most unique agave seedlings is a selection of Agave lophantha in which the tips of the leaves turn bright gold during the cold winter months. Here is our parent clump that’s been in the ground since 2011. Hopefully just a few more years and we’ll have enough to share…assuming there is any interest.
When creating hybrids, especially with plants like agaves, it takes many years to know exactly what the offspring will look like. We have a pretty good guess, since we’ve done this for so long, but here’s an updated photo of a cross we made in 2013 of Agave striata x Agave lophantha. The hybrid, that we call Agave x striphantha is now 3′ wide, which is the same width of the Agave striata parent. We expected the hybrid to stay a bit smaller, but it did not. What we still don’t know is what will happen when it flowers. Agave striata is the only hardy species that doesn’t die after flowering, while the flowering rosette of the other parent, Agave lophantha cashes it in after its sexual encounter. Hopefully, it won’t be long before we know about the hybrid, and hopefully it will produce viable seed.
There are many agave that are hardy in our Zone 7b garden that many people would not think would live here. The key to successfully growing agaves is proper siting, planting, and culture. These are pictures taken this week of agaves in the garden.