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.
Late spring is a great season for clematis at JLBG, but one that’s particularly of interest is the recently named (2006) Clematis carrizoensis, which hails from a very small region of East Texas. It’s not been around long enough to officially be listed as Federally Endangered, but that’s most likely where it’s headed. This new species is part of what’s know as the Clematis viorna complex. In the garden, it’s a short vine, but we chose to let it have its way with a century plant, which provides a lovely structure for the months of flowering.
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.
For those who regularly attend our Open Nursery and Garden days, you have no doubt watched the evolution of our new dryland rock garden by our welcome tent. I thought it would be fun to look back at its short evolution. Below is Jeremy’s bed outline from late January 2021, when this new bed was only a vision in our heads.
In late January 2021, Jeremy broke ground by digging down until we reached undisturbed subsoil, which was then loosened.
The next step was to add our planting mix, which consists of 25% native soil, 25% compost, and 50% Permatill (a popped slate gravel). The planting media was thoroughly mixed with the subsoil, which ensures continuous drainage by not layering different soil types. The final height of our bed was 5.5′, with the knowledge that we would loose about 6″ in final height to settling. Planting began in early March 2021.
Below is the same area taken this week–27 months after construction. The bed is 35′ long with an average width of 15′, which would give us 525 square feet of bed space–if the bed was flat. With our finished height of 5′, we actually have close to 800 square feet of planting space–50% more surface area, all because we raised the bed height.
Because these are dryland plants, this section of the garden is un-irrigated, except during extended periods of severe drought and above normal heat. We hope this “peaks” your interest in both the science and art of rock gardening. If so, the North American Rock Garden Society (NARGS.org) is an amazing group of like-minded folks with an incredible seed list of treasures for this type of garden.
Looking great in the garden now is the false red agave, Beschorneria. Beschorneria is a small, little-known genus of only 8 species of plants in the Asparagaceae family–first cousin to the better known genus, Agave. Beschornerias are native from Northern Mexico, south to Honduras. Through the years, we’ve grown 7 of the 8 species, having not bothered to try B. wrightii, due to it’s tropical origin.
The only species that has proven reliable and evergreen here is Beschorneria septentrionalis–a species introduced by the former Yucca Do Nursery from their collections in Northern Mexico.
Several years ago, we were given seed of hybrids of B. septentrionalis x B. yuccoides ssp. dekosteriana. Most of the hybrid plants died because they inherited too many genes from the more tender B. yuccoides, but two plants still remain. Below is one we named Beschorneria ‘Fire Towers’, which appears close to B. septentrionalis in appearance, but perhaps with a bit more vigor.
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.
Agave ‘Crazy Horse’ is an amazing agave hybrid we purchased back in 2005 from an Ebay seller in Texas. The vendor had found the plant growing at a real estate office in Montgomery County, Texas. It’s obviously a hybrid, but we still don’t know the parentage for sure. If we had to guess, it appears to be a hybrid of Agave x protamericana and Agave cupreata. In the 18 years, we’ve grown it, it’s been an exceptional plant, forming 3.5′ tall x 5′ wide rosettes, and suckering tightly against the main clump. This year, it sailed though our winter cold of 11F. It’s been almost a decade since we’ve offered this, so perhaps it’s time we propagate a few more to share.
In 2011, we spotted a tiny creamy white streak on a single leaf of a small pup, which was potted for further observation. After several years, and thanks to crown cutting, we were able to produce a highly-streaked plant, which we call Agave ‘Craziness’…see below.
Several years later, we were able to isolate the streaked leaves into a stabilized central variegation we named Agave ‘Bareback Rider’. Although winter hardiness also disappears with the creamy white foliage, it still makes a superb container plant. With that much white in the leaf, the growth rate has also slowed dramatically. It’s our hope that within the next year or two, we can finally release this amazing form through Plant Delights.
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 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.
Our oldest clump of the North American native Agave lophantha ‘Splendida’ is preparing to celebrate its 10th anniversary in the garden at JLBG. What started as a single pup, now has an extended family. Please join us in sending birthday wishes to this great century plant selection.
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.
Here’s a new photo of Agave parryi ssp. huachucensis ‘Excelsior’ from our garden this week. We typically don’t have many variegated century plants that will survive our winters, but this is one of the exceptions. This superb clone was first introduced in 1967 from a small California nursery by the same name. Protection from excess winter moisture and exceptional drainage is always the key in cold, wet winter climates. This particular planting is under a roof overhang. Hardiness zone 7b to 9b.
In 2014, we decided our goal for the years’ century plant breeding project was to see how large a Zone 7b winter hardy agave we could create. We had seven agaves flower that year, but only two had the epic proportions we required.
One of those was a selection of Agave x protamericana from a Yucca Do collection in Northern Mexico. By the time of flowering at 15 years of age, it had reached 5′ tall x 9′ wide.
Agave x protamericana and Agave americana are the two largest blue-foliaged agaves, but only Agave x protamericana is winter hardy for us, here in Zone 7b, since it also has some ancient genes from the hardier Agave asperrima, which adds slightly to its winter hardiness. You can distinguish the two plants by feeling the back of the leaves. Agave americana has smooth leaf backs, while Agave x protamericana has sandpapery leaf backs. The largest size listed for Agave americana in Howard Gentry’s Agaves of Continental North America, is 6′ tall x 12′ wide.
At the same time we had a blind flower shoot on our giant Agave x pseudoferox ‘Bellville’. Agave x pseudoferox is another ancient Mexican hybrid in need of a DNA workup. We think it’s probably a hybrid of Agave x protamericana with Agave salmiana var. ferox and possibly Agave gentryi). Commercially, it’s usually called Agave salmiana var. ferox, which is similar in appearance, but with absolutely no winter hardiness.
Prior to full flowering at 15 years of age, our giant specimen of Agave x pseudoferox ‘Bellville’ had reached a mature size of 4′ tall x 8′ wide. We were able to make the cross prior to it fully flowering, by using something we mentioned above that we call “blind shoots” or boners.
Being monocarpic plants, the rosettes of most agave species die after flowering, but side shoots are an interesting phenomenon we see on all of our Agave x pseudoferox cultivars and hybrids. These “blind shoots” emerge from underground stolons instead of from a rosette. They are much shorter than normal flowering shoots which emerge from the rosettes (2′ tall vs. 20′ tall), and they have no impact on the life expectancy of any of the rosettes.
In the case of Agave ‘Bellville’, our plant began producing blind shoots five years prior to the clump producing a full size, rosette-based flower stalk. The beauty of blind shoots is that they breed and pass along characteristics of the parent without the need for a tall ladder.
We gave our hybrids the seed strain cultivar name, Agave ‘Bluebell Giants’. From these, we selected 23 clones, which were planted in the trial fields in 2016. Of those, only 4 survived our subsequent trials for winter hardiness.
Our best and most winter hardy seedling from the cross pictured below is now 6 years old in the garden. We’ve given this the name Agave ‘Supersize’. It has achieved a size of 6′ tall x 8′ wide in that time. To put this in perspective, it is larger at 6 years old than both parents were at 15 years old. If Agave ‘Supersize’ waits until age 15 to flower, it could easily reach more massive proportions that any Zone 7b winter hardy agave in existence.
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.
As fall temperatures drop, it’s not unusual to find our native bees asleep in some of the most interesting places. We caught this carpenter bee fast asleep on the job this week, clinging tightly to the spines of an Agave parryi.
Our 2016 century plant hybrid is looking quite lovely in the garden this month. This plant, which we named Agave x victorifolia ‘Prince of Whales’, is a hybrid of the Whale’s tongue century plant, Agave ovatifolia (male parent), and the Queen Victoria century plant, Agave victoriae-reginae (female parent).
Since both parents are non-offsetting, this means that the offspring will grow to maturity, flower, then die. Consequently, in order to be able to propagate and share, we will have to drill out the central core of the plant to trick in to offset. While this ruins the appearance of the original, it’s the only way for this to ever be shared and preserved. This plant has been in the ground since 2018, so we expect to have another eight years (guessing) prior to flowering. Consequently, so we’ll probably gamble on waiting a few more years before performing surgery. Winter hardiness is Zone 7b-10b.
Below is a photo of both parents.
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.
Looking lovely today is the amazing Agave x romanii ‘Shadow Dancer’. This fascinating agave is a man-made hybrid between two Mexican species, Agave filifera and Agave mitis. Not only is it a hybrid, but this selection has a fascinating variegation pattern that’s not seen on any other century plant. The new growth emerges ghostly cream with a muted green border. As the leaves age, they green disappears and the leaves become pure parchment white. Despite the seeming lack of chlorophyll, Agave ‘Shadow Dancer’ has amazingly good vigor and doesn’t burn in full sun. This has potential winter hardiness for Zones 8b and south, but needs more trialing to know for sure. In other climates, it’s a great container specimen.
A few weeks ago, we posted images of the flower spike of our Agave ovatifolia ‘Vanzie’ just beginning to spike. Now, the giant beast is in full flower. The first photo below is the plant with its full expanded stalk in full bud, just prior to opening. After that, each image shows the progression of the flower development.
Agaves are monocarpic, so those species like Agave ovatifolia that do not make offsets will die after flowering. Agave ovatifolia is, however, one of a handful of species that usually forms baby plantlets on the tip of flowers stalk after seed set.
First flowers just beginning to open
We set up our Little Giant ladder, which allows us to climb up, collect pollen and to make crosses with other agaves.
The lower flower clusters open first and flowering continues to progress each day moving higher up the stalk.
Climbing the ladder gives you a bird’s eye view of the amazing buds as they are ready to open…usually 200-300 per panicle.
Below is a half-open flower panicle. The pollen is ripe before the stigma is ready to receive pollen, so pollen can be easily gathered without worry of self pollination.
Below is a fully open flower panicle. Each panicle weighs 5-10 pounds. No wonder the stalk needs to be so sturdy. Once the temperature warms in the morning, the flowers are abuzz with pollinators…mostly bees.
Looking down from above the flower panicle makes a pretty crazy photo
Our intern Zoe is working with our volunteer agave curator, Vince Schneider to gather pollen and make crosses with other previously gathered agave pollen
I usually don’t climb this high…a fear of heights, but this photo opportunity was just too good to resist
In case you missed this section of the garden during spring open house, this is where we created a small vignette that comprises both bog and desert conditions in the same space. The low central area was created for pitcher plants and other bog lovers, while the higher areas to each side, are home to dryland loving plants like agaves and bearded iris. We hope to show how dramatically diverse habits can be created in a very small space. The wet space is created by installing a seep, which is nothing more than a continually dripping water line.
Just over a year ago, we built a new berm garden, adjacent to our Open House welcome tent. Here is that garden today. The soil is composed of 50% Permatill (slate gravel), 25% compost, and 25% native soil). This is in an unirrigated section of the garden. Like all garden spaces at JLBG, no commercial fertilizers are ever allowed. The exceptional drainage and high nutrient content from the compost and Permatill result in an amazing growth rate.
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.
We’ve “enjoyed” frozen precipitation for three consecutive weekends this winter, with one producing a decent 3.5″ snow. There’s something magnetic about snow on century plants, that makes you grab your camera and snap away.
The white of the snow looks out of place on an agave, although it does wonders for accenting the architectural structure of the plant. We have worked for 35 years to identify and create agaves which are completely tolerant of such weather events. Below are a couple of our hybrids, created here at JLBG.
Since we’ve been growing agaves, one of the most fascinating things we’ve noticed is the incredible attraction of tree frogs and Carolina anoles to their leaf texture. There is hardly a day that goes by that we don’t spot one or the other, nestled on an agave leaf. Here is our most recent image of our native green tree frog, Hyla cinerea, basking in the sun on an Agave parryi hybrid. Ain’t nature grand!
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.
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.
We have just completed our fall inventory and found some of the coolest plants didn’t sell in the numbers that we’d hoped, so we’re left with extra inventory. Take advantage of this opportunity to get 20% off on over 125 unique plants, many of which you won’t find anywhere else. Quantities are limited so shop now while supplies last.
Here is just a small sampling of some of the horticultural gems you will find: