Our garden patch of Agave lophantha ‘Splendida’ is looking rather splendid this morning as we approach December. This patch started as a single rosette in 2013, so has now been in the ground for a little over a decade. We think it’s one of the best forms of the North American native Agave lophantha that we’ve ever grown. This originally came to us from our friend Ted Stephens of Nurseries Caroliniana.
Our oldest clump of the amazing Agave nickelsiae (formerly A. ferdinandi-regis) is now over a decade old, so we’re probably within five years of flowering. Often confused with the similar Agave victoriae-reginae, this North American (Northern Mexico) endemic is somewhat similar, but has more leaves, darker spines, and more prominent leaf markings.
Some seedlings offset, while others, like this selection, do not, so this will die after it flowers, but not before we spread its pollen far and wide on every other flowering agave we can find. It’s still hard for us to comprehend that such an amazing plant is actually growable in our garden. Obviously, bright sun, and well-drained soils are the key. Hardiness Zone 7b-10b.
I remember looking in astonishment at the first published photos of the newly described North American (Northern Mexico) native century plant, Agave albopilosa, with disbelief. Could this really be real, and if so, how did it escape being discovered and published until 2007. It turned out not to be an April Fools photoshop joke, but indeed an amazing new botanical discovery.
We were finally able to acquire seed in 2010, and again in 2013, so our oldest plants, pictured below, are now a decade old. It took about 2 years for the cotton balls to begin to form on the leaf tips, but like most century plants, Agave albopilosa turned out to be easy to grow, albeit insanely slow. It’s so slow, that commercial production will probably always be limited to small specialty nurseries. It’s been interesting to observe the genetic differences of the species, as you can see below. Some of our seedlings are non-offsetting, while others produce numerous offsets.
The first plant that I’m aware of to flower in the US, occured this summer at Walters Gardens in Michigan. Below is plantsman Hans Hansen, showing off his baby, before the pollen is removed for breeding purposes. Because it’s a cliff dweller, the flower spikes found it more reasonable to hang downward. If the cotton balls are heritable, as they should be, I see no reason within a decade that we can’t have giant century plants in our gardens with cotton balls at the tip of each leaf.
Agaves are an amazing architectural addition to the garden with their form and radial symmetry. We just captured this image of one of our Agave x loferox hybrids, that we named ‘Magical Moments’. The result turned out very artsy.
The first photo below is our hybrid century plant, Agave x ocareginae ‘Oh Victory’, from a cross we made in 2014, between Agave ocahui and Agave victoriae-reginae. The plants went in the ground in 2017. Of the eleven seedlings we selected and planted in the ground, only five have survived.
Below you can see both parents, first Agave ocahui, which supplied the pollen, and below that is Agave victoriae-reginae, who was the mother. The hybrid has leaves that are intermediate in width between both parents. Our hopes were for the offspring to have the white markings of Agave victoriae-reginae, which didn’t happen. Now, we’ll wait for these to flower, and hope we can get seed that produces a F2 generation with the white markings, which seem to be a recessive genetic trait.
Introducers of new century plant selections are challenged with coming up with appropriate cultivar names, often have a propensity to use wordplay, referring to the agaves spiny teeth. Two favorites, we photographed this week are below, Agave titanota ‘Snaggletooth’ (top), and Agave titanota ‘Sabertooth Tiger’ (bottom). Both are mutations of the same original plant, the later was derived from a mutation that flipped the pattern from an edge to a center. Agave titanota is prized as a summer patio container plant due to its relatively slow growth rate. Plants must be stored indoors for the winter when the temperature drop below 40 degrees F.
Plant breeding is a wonderful hobby that attracts an array of hobbyists, as well a plant professionals. Many plants, such as hemerocallis, hosta, hibiscus, and iris, are so easy that they attract the majority of hobbyist breeders. Professionals and the craziest of the breeders occasionally focus on more difficult plants that few others are willing to try. This includes plants where the pollen exchange is complicated either by timing, incompatibility, or other constraints. Such is the case with century plants (agave).
Peak flowering season for 2023 is drawing to a close at JLBG, while one new agave is just in mid-spike. We only had 13 different agaves flower this year, compared to 18 last year. Fortunately, we are able to save and store pollen in the refrigerator, where it will remain viable for at least 5 years.
Below are a few images of Steve Guptill of our garden staff, as he made crosses last week. At the bottom of the first image is our volunteer agave specialist, Vince Schneider, who is training Steve to make the crosses.
With agaves, the process involves waiting for the stigma to become sticky–a sign that it’s receptive to the pollen. Pollen is then gathered from our prospective father and then hauled up the 21′ ladder to the waiting stigmas. Not only are you high in the air, but you’re working around hundreds of bees that are busy gathering copious amounts of nectar.
Assuming we get seed set, they should be ripe by late September/early October.
Both spiking agaves in the photo below are our selected hybrids from previous years breeding.
It’s fascinating to see how many amphibians in the garden are drawn to agave leaves. We find more amphibians resting on agaves than any other plant in the garden. Here is our latest image capture of our native green tree frog, Hyla cinerea.
So often we think we know all about a plant, when we’ve only grown a single clone, and we all know what happens when we assume! A good example is the Southwest US native Agave parryi ssp. truncata, which is now grown around the world. 99.9% if the plants in commerce are a single clone, know as the Huntington form. Unfortunately, this clone is not reliably winter hardy north of Zone 8b.
Many years ago, we received a new clone via the late nurseryman, George Hull. Having survived for us without damage since 2010, including two winters of single digit F temperatures, we have christened this Agave parryi ssp. truncata ‘Hardy Boyz’. Below is a photo taken last week. It’s been very slow to offset, but we feel this an exceptional clone worthy of propagation and distribution. Stay tuned.
We were thrilled how well Agave x protamericana ‘Silver Surfer’ came through the 11 degree F. cold snap this winter. This 2007 Plant Delights/JLBG agave introduction was our selection from a Yucca Do Nursery seed collection in Northern Mexico of a naturally occurring hybrid between Agave americana and Agave asperrima.
Agave x protamericana ‘Funky Toes’ is looking fabulous in the garden today, having sailed through our cold winter in tip top shape. This unique form of the well-known North American native agave is an introduction of the former Yucca Do Nursery, from one of their collections in Northern Mexico.
In 2018, we found a streaked leaf on a potted offset. By using a technique called crown cutting, we were able to isolate the bud from the streaked leaf into a yellow center, which we named Agave ‘Funky Monkey’…photo below. Hopefully in the next few years, we’ll have enough of this new introduction to share.
I had to chuckle as folks on several Facebook plant groups were wringing their hands in worry prior to the recent cold snap, while we were secretly hoping for even colder temperatures than forecast.
JLBG registered three consecutive nights in the teens recently; 11F, 19F, and 19F. While this was certainly not abnormal for our area, folks with very short memories thought the horticultural world was coming to an end. In reality, we recorded similar temperatures in the winter of 2017/2018, albeit a week later that year.
When we first started the gardens at JLBG, we were squarely on the Zone 7b side of the Zone 7a line. We are now on the Zone 7b side of the Zone 8a line. In order words, we have shifted about 1/4 of a hardiness zone. Since 2018, JLBG has registered three consecutive Zone 9a winters, so it’s not surprising the new gardeners or those with short memories start assuming that all kind of plants are reliably winter hardy, which is not the case.
We long for cold temperatures because we want and need good winter hardiness data, and while mild winters may be enjoyable to us Homo sapiens, we don’t learn anything about plant hardiness from those winters. So, here are a few things we learned this year.
Agave bracteosa ‘Stingray’ is the most winter hardy of all brightly variegated agaves we’ve tried. Here is our plant looking quite lovely after our 11 F cold.
Agave weberi ‘Stone Cold Austin’ is Patrick McMillan’s collection of Agave weberi from Austin, Texas. We’ve tried Agave weberi a couple of times prior, and could never get it through one of our milder winters. Patrick’s original plant at Clemson got large enough to flower there, so we’re hoping for the same. The older foliage is showing damage from 11F, and will most likely be lost, but the bud seems fine so far.
We’ve never had any luck with any of the dwarf Agave lechuguilla mutants we’ve tried in the garden, but this new one, shared by plantsman Hans Hansen, that we call Agave ‘Tater Tot’, had no problem with 11F. These are often sold as Agave x pumila, which actually doesn’t exist. Everyone assumed that A. x pumila was a hybrid, but when one in Europe recently mutated back to the original form, it turned out to be nothing more that a super dwarf form of Agave lechugullla.
Mangave ‘Racing Stripes’ is a plant we had high hopes for in terms of winter hardiness, but we had not had a cold enough winter to get good data. Our only reservation was that it contains genes from the tropical Agave gypsophila. Thankfully, our plant came through the 11F freeze in reasonably good shape. The wrinkled nature of the older leaves are indications of cold damage that will show up in a few more days, but the core seems intact and should re-grow.
We fully expected Bambusa multiplex ‘Green Giant’ to be defoliated after 11F and the stalks killed to the ground, but our fully exposed clump still looks like it’s mid-summer…at least from the north side.
On the south side, the same clump has fried foliage. There are typically two causes for such damage. One is wind desication when the winds are blowing from a single direction and the ground is frozen, making it impossible for the plant to replenish water lost through the foliage. During the time that our ground was frozen, our winds were coming from the West, so that wouldn’t account for damage only on the south side of the plant.
In this case, the more likely scenario is that this is due to sun scorch when the soils was frozen, since the damage is on the south side. If the canes are indeed undamaged, as it appears, new leaves should reflush in spring.
We didn’t hold out much hope for the Mexican palm, Brahea decumbens, but it sailed through 11F unscathed.
Since we know that genetics matters, we will often plant more than one clone of a marginal plant like a new palm. Below are two seedlings of the small-seeded European Fan Palm, Chamaerops humilis var. microcarpa. The first shows significant foliage burn, while the second plant, growing nearby shows no damage after 11F.
The hardiest of all Sabal palmetto forms are those from NC’s Bald Head Island. Our plant from there came through the cold unscathed. We expect many local businesses and even homeowners who purchase large trunked forms directly from Florida growers will probably be in for a disappointing spring.
All of our hardy cycads have assumed the straw-color we see every year when the temperatures drop below 18 degrees F. The plants are fine, but we recommend waiting to remove the dead fronds, since doing so now, can cause the new foliage to emerge in the middle of winter, which is never a good idea. April 1 is our target date to remove the fried foliage.
One of the real surprises was the fried foliage of Viburnum ‘Moonlit Lace’, where it was growing in full sun. The same plant growing in shade looks untouched. The stems are fine and the plant should re-sprout fine, but gardeners who grow this in full sun may be disappointed.
This is the coldest temperatures we’ve seen since planting Patrick’s hardy selection, Opuntia microdasys ‘Dripping Springs’. Our clump looks great after the cold. It’s hard to imagine that this clone is so much more winter hardy than any of the other forms of this species that we’ve tried previously and killed at much warmer temperatures. Although we don’t offer this for sales, I’ll remind you of our great prickly pear cactus giveaway at our Summer Open Nursery and Garden in July.
The Mexican Sedum praeltum looks a bit sad, but actually seems to be fine with sound buds up and down the stem. This little-known perennial forms a plant that looks almost exactly like the tender Jade plant, Crassula ovata.
Lastly, our patches of Living Stones, Lithops aucampiae, sailed through 11 degrees F. I wonder if we can ever get all the disinformation on the Internet regarding their tolerance to cold corrected.
Looking great in the garden this week is Agave x pseudoferox ‘Green Goblet’. This 1996 introduction from the former Yucca Do Nursery is one they found in Mexico and brought back as a single pup. Our original plant flowered in 2011 after 11 years in the ground, so this specimen has re-grown from one of the remaining small pups. Since we’re now at 11 years since last flowering, we’re preparing for a new blessed event. Since we can usually tell by now if it’s expecting, which it is not, the odds are pretty good for a 2024 flowering. Plant Delights Nursery will be offering A. ‘Green Goblet’ for sale in 2023.
Last week, we were repotting our container agaves prior to winter, when we ran up on this unusual sight. Let me begin by explaining that there are three groups of agaves, based on how they propagate: solitary agaves, rhizomatous agaves, and offsetting agaves. While it’s not unusual for a rhizomatous agave to produce an underground shoot in container, this level of underground shoots is highly unusual. What is even stranger is that this is a non-rhizomatous cultivar.
Since some agaves are poor or non-offsetters, the only way to force them to multiply is to remove the apical bud, either by means of coring, or drilling. Once this is done, the agave usually forms offsets in the remaining leaf axils. For some reason, when this plant of Agave ‘Ripple Effect’ was cored, it went nuts by developing underground rhizomes.
Left to its own devices, there will be one plant produced from the growing tip of each rhizome. There is, however, a dormant bud every few inches along the rhizome, so in theory, this could produce hundreds of plants if we can figure out how to make the dormant buds break. Below are the shoots after we unwound the twisty rhizomes.
We love the spineless Agave bracteosa ‘Stingray’ in the garden. We’ve had these dotted throughout the garden since 2017, and so far, with good drainage, they’ve handled our winters quite well, which is certainly not normal for a variegated century plant. This particular species prefers part sun to light shade. Hardiness is Zone 7b/8a and warmer.
We posted this a few weeks ago as our Agave ‘Mountain Man’ (A. gentryi x montana) prepared to open. We’ll, the big moment is here…below are a few shot from today.
The seed were wild-collected in Mexico in the late 1990s by our friends at Yucca Do, and our seedling was planted in May 2000, so it took 17 years to flower. Fingers crossed for good seed set, and fortunately we have many more agaves in flower (and a tall ladder) to help the process. 
