[I wrote this originally about 2 years ago as part of what turned out to be a too long look into the Bromeliad Family. Here I present only the genus Puya spp. in an edited form with the addition of the species Puya berteroniana. Go to the original article to read about the shared evolution of the several genera and families that comprise the family, why these are not considered succulents and a look at the armed defenses of many plants. My plan is to breakout at least some of the other genera as well as I think the length of the original post may have put some readers off.]
Puya: one of the Xeric Genera of Terrestrial Bromeliaceae
The name “Puya” comes from the Mapuche Indian word meaning “point” (The Mapuche people are indigenous to Chile and Argentina. They constitute approximately 10% (more than 1.000.000 people) of the Chilean population. Half of them live in the south of Chile from the river Bío Bío to Chiloé Island. The other half is found in and around the capital, Santiago and were mostly forced to the city after Pinochet privatized their lands giving them to the wealthy.)…the assignation is clear and the pointed, spiky, nature of this genus is immediately obvious to anyone. But there is something easy and comfortable about the sound of the word in your mouth when you speak it…poo-‘yah. Puya are native to the arid portions of the Andes and South American western coastal mountains. (Oddly, two species are found in dry areas of Costa Rica.)
Puya spp., populate arid western regions of the Andes Mountains up into southern Central America. These are terrestrial plants, relying on their roots to find the moisture that they need. They possess the same basic rosette structure common to all members of the Bromeliad family to which they belong, including their petiole-less leaves, which clasp directly to a compact stem structure, funnelling the infrequent, and seasonal, precipitation they get into their crowns and root structures where they can take it up, a strategy very similar to Agave and Aloe which grow under similar conditions.
A Brief Look Into the Metabolism of Puya spp. and its Subgenera
Over the course of millions of years, as the Venezuelan highlands and later, the Andes lifted, the Bromeliad family adapted and speciated to better fit the higher, drier, climate transforming their metabolism into what we now identify as the CAM photosynthetic pathway. These plants utilize solar energy captured in the daylight hours, transforming it into ‘ATP’, a metabolite that provides ready energy for other chemical reactions, working as a kind of biological ‘battery’ that can be charged, spent and recharged, as do all photosynthetic plants, but this time producing the organic compound, crassulacean acid. This compound is ‘stored’ until nightfall, when leaf stomata open allowing in CO2, to complete the process transforming it into the carbohydrates and manufacturing the other metabolites that the plant later uses to power its cell growth and build its needed tissues and structures. By separating the process in this way these plants are able to greatly lower their water loss, minimizing the effects of high temperatures, but, in the process, greatly slowing the overall growth rate of the plant.
The C3 pathway is the oldest and most commonly utilized strategy by plants. It contains basic processes common to all plants, though it does this by a more ‘open’ process that produce a 3 Carbon molecule instead of Crassulacean Acid. The C4 process, a third less common pathway, utilizes a 4 Carbon molecule in a process that attempts to isolate its stages in different organs, reducing both water loss as well as those losses due to oxidation. This oxidation or respiration reverses the ‘first stage’, returning oxygen to CO2, losing the energy it had just captured. The C4 process is intermediate, producing quicker growth than the slower CAM plants while wasting more water and energy through their less controlled respiration, or oxidation. C4 plants are however more efficient than C3. Respiration losses are much higher within both C3 and C4 because the Oxygen they produce is available to reverse the compounds they just produced. C4 plants, an adaptation to drier conditions, separate their internal chemical processes physically in such a away that, oxidation, respiration losses, are reduced. The C4 process is most commonly found in dryland grasses. CAM is the most water and energy efficient pathway…it is also the slowest. They tend to grow where C3 plants would have great survival difficulties. (See previous postings for a more detailed description of these alternate forms of plant metabolism.)
There are 199 species of Puya, two of which are found in Costa Rica, the remainder and vast majority, are all found in South America. These are frequently divided into two subgenera, Puya which includes only 8 species, and Puyopsis, which include the other 191 species, based on differences in their inflorescences, their flowering structures. The inflorescences of all Puya species vary widely, in size, structure and flower color. Two characteristics consistently occur within the subgenus Puya, the terminals of the branches on their inflorescence are sterile, the flowers generally being incomplete and aborting over the development process, giving them a spare more spiky appearance. These also tend to bloom progressively over time from the base to the apex. Of the species I discuss below, three, Puya chilensis, P. raimondii and P. bertoniana, are in the subgenus Puya. This spiky aspect of subgenus Puya has given rise to the idea that these branch ends are intended to serve as perches for passerine birds who are thought to play some role in pollination. Well, apparently they do, but it is not the sole factor in determining which pollinators visit a given species.
Multiple factors determine how a plant is pollinated. The European Honeybee is only one of thousands of possibilities, though the odds of its involvement have been skewed in its favor in North America, as we continue to actively promote it through agriculture while compromising native pollinators through habitat destruction, loss of species and the use of insecticides. In undisturbed landscapes such as in South America where Puya occur naturally they are pollinated by their own resident bees, as well as Hummingbirds…and certain species of passerine birds…which dominate vary with between species. In general most species are visited ty a range of pollinator species. Pollinators are attracted by taste, scent and color. It is thought though that Hummingbirds have a poorly developed sense of smell which would nullify any advantage to producing a scent for a flower. This is reflected in the fact that most Puya spp. aren’t particularly fragrant. The size of an inflorescence can be a factor especially with plants like Puya raimondii which possesses one of the largest inflorescences in the world. Such a single structure can make it well worth a pollinator’s efforts to seek it out. As is true with other plant genera flower structure also plays a role in the success of pollinators as it can increase or decrease the likelihood of successful pollination.
Studies have been done to test whether the sterile tipped branches on subgenus Puya spp. increase the likelihood of pollination by passerine birds, those birds that ‘perch’. The answer is incomplete. Yes, these birds do perch on these structures and they do help pollinate them, but they also pollinate Puyopsis species, without this branching, though in smaller numbers. Puyopsis species tend more likely to be pollinated by Hummingbirds, although Hummers will also visit those plants in the sterile branched Puya subgenus. Bees will visit both. It has also been suggested that the quantity and composition of the nectar itself plays a role in the selection of pollinators, at least between the two broad groups of birds. Hummingbirds, with their high energy requirements, especially those living at higher, oxygen thin elevations, are more likely to visit Puyopsis species since they tend to produce nectar that has more concentrated sugars and that these sugars tend to be in the form of sucrose. There seems to be some truth to this though some species of passerine birds will visit these as well. Those plants with lower sugar concentrations tend to produce higher quantities, volumes, making them more attractive to passerine birds and helping them meet their water requirements in the arid highlands where open water can be scarce. Also, these nectars with lower concentrations contain glucose and fructose, predominately, sugars that don’t require the ‘sucrase’ enzyme to digest. Hummer’s are plentiful producers of this enzyme and so are physically capable of better digesting sucrose. In more recent years it has been found though that many passerine birds produce this enzyme in smaller quantities and so can digest sucrose sugars as well. This is why pollination is somewhat of a mixed bag in terms of pollinators. This is also why species of the entire genus tend to produce relatively large quantities of nectar as the capacity of birds is greater than insects. In this the genus is somewhat like Agave which also are a source of nectar for hummingbirds and bats as well, though the composition of their nectars has evolved somewhat differently to meet the particular needs of their pollinators. It has been suggested additionally that in the arid higher elevation mountains that passerine birds might meet some portion of their water requirements from the higher sugar concentrated nectars on those species with up facing flowers which can collect rainfall or dew, reducing the effective concentration of their nectar.
An interesting side note, Hummingbirds have been found as high as 17,000′ in the Andes. At these elevations the concentration of O2 in the atmosphere is very low, and should be a limiting factor in any animal’s metabolism. Many species, including humans, have difficulty functioning this high. Additionally hummingbirds have metabolism rates many times higher than those of even the best conditioned human athletes. Metabolism requires the use of O2. Because it is in limited supply at these elevations hummingbirds should not be able fly and live as they do…yet they can, due to an adaptation of their hemoglobin which allows it to bind to more O2 thereby carrying higher quantities of it throughout their bodies to help power them. Their muscles also produce much less lactic acid when in low O2 conditions…lactic acid causes us to feel ‘heavy’ during exercise and slows our bodies movements, frustrating our intent.
Puya chilensis (subgenus puya)
Puya chilensis, is native to the arid coastal mountains of Chile where they share space with sclerophyllous plants, characterized by their small, leathery, evergreen, leaves…and native cactus. Puya chilensis, with their rosettes of long, strappy, somewhat stiff, channeled, evergreen and barbed leaves, fit right in and can be found on slopes very close to the ocean, down to 50′ or so elevation, and as high as 6,000′. It shares part of its range with the endangered palm, Jubea chilense and a bamboo, Chusquea cumingii. Sandwiched between the ocean and high Andes, its range is delimited by the Atacama Desert to the north and the rainforest, Lakes District, to the south. The Atacama, considered to be the driest desert in the world, stretches a 1,000km north and south within the Andes rain shadow. In Chile, these landscapes are called mattoral and are very similar to California’s chaparral and share their ‘mediterranean’ climate. Like the other larger Puya species some consider these to be proto-carnivorous, entrapping animals whose remains ‘feed’ the soil and then the plants, as they decompose. I can almost imagine their terror at becoming entangled with each struggling move only worsening their plight!
This is another acquisition for me from Annie’s Annuals, I couldn’t resist her description…we shall see how long I can keep it! It forms a rosette 5’ tall with truly formidable foliage as you might have already guessed. The flowers though are the aesthetic ‘hook’ forming on 12’ stalks and blooming for a few months beginning in Spring. It takes 10-15 years to bloom, sometimes as long as 20, but thereafter blooms every spring…one of the few Puya that are not monocarpic.
Puya chilensis, as a mediterranean plant, experiences 3-5 months of drought across the warm summer months, receiving up to 16″ during the ‘wet’ winter months. Further north, it grows with drought periods as long as 10 months with as little as 4″ of rain. You are most likely to find this Puya on north facing hillsides, between 1,000′ and 3,200′ though it is also commonly found on relatively flat sites. (Recall that in the southern hemisphere north slopes are the hot, sun facing side!!! I sometimes forget this!) In hotter areas, and remember, that at these lower latitudes, the sun can be more intense than in our higher, more temperate latitudes, that these are sometimes found in the partial shade of relatively open canopy. Think of California chaparral country when siting!
My P. chilensis is confined to a pot, which, because of its ultimate mature size will in all probability keep me from growing it into its flowering maturity…yet I have it! It will be big and heavy, two characteristics that will cause its lifting and handling ‘delicately, to be difficult, and, consequently, a more ‘bloody’ affair. This plant has to be a ‘9’ on the ferocity scale, it gains in fierceness, with increased stature. As terrestrials, Puya depend on their roots to take up moisture so unlike their epiphytic cousins and true succulents these will demand relatively large soil volumes/pots to grow into healthy specimen. Additionally, confined in too small of a pot many terrestrial Bromeliads are difficult to water, simply getting a hose or the spout of a watering can to where they can reach surface potting soil can be difficult due to the stiff downward arcing foliage which can shed much of water out and away. If watering from the top the arcing rosette will tend to channel some toward the center…if it doesn’t come too quickly. This characteristic likely aids the collection of water for this Puya as its maritime location receives much moisture in the form of condensation from fog, a condition that also helps moderate the region’s temperatures.
If I were to plant this one out it would have to go at the top of my south facing retaining wall where the natural drainage is probably the best and the sun exposure to its liking. I would have to change out the rest of the planting as those there currently require supplemental summer water. I would also add ‘grit’ to the soil to improve the drainage around the crown, but I’d also likely have to add some protection during our wetter and colder winter periods. I haven’t decided about this option. In an ‘experiment’ I planted my Chusquea cumingii, a resident of the same region as well as a Fabiana imbriacata var. violacea, also a Chilean resident of the same region, (see my posting here on Fabiana.) on this retaining wall, the later of which has been successful in multiple relatively unmodified sites in Portland.
Puya raimondii (subgenus puya)
Each of the around 200 species of Puya, have their own particular range and preferences. Puya raimondii, Queen of the Andes, is restricted to the arid high Andes of Peru and Bolivia, where it can be found in the Altiplano, an arid high elevation plateau, averaging over 12,000′, lying between two ranges where the Andes are at their widest, just over 200 miles across. The ‘high plain’ stretches south from central Peru across Bolivia, where Lake Titicaca is located near their shared border, all of the way down to northern Argentina and Chile, the bulk of it in Bolivia. It is bound to the east by the Cordillera Oriental and the Amazon Basin, to the west by Cordillera Occidental with the Atacama Desert to its southwest. Active volcanos abound in the surrounding mountains. Most of the Altiplano lies within a huge basin out of which no rivers flow. The plateau averages less than 8″ of rain a year which it receives mostly in the summer months coming from the east where most of it is wrung out climbing the eastern slope of the Andes. The rest of the year is cool, dry, windy and sunny…desiccating conditions. Keep this in mind. Were you able to acquire one of these Puya raimondii protection from winter wet would be high on its list of needs as our pattern is opposite and more extreme than its own.
P. raimondii, is found primarily, in the ‘warmer’ northern portion of the Altiplano into Peru, including Huascarán National Park which covers over 1,300 sq.mi. It typically does not freeze where it grows, this is a ‘tropical’ area despite its elevation. It would then prefer to neither freeze nor bake. It is the largest and tallest of the genus and family, its vegetative rosette base reaching nearly 10’ tall, its inflorescence to 23’+ even up to 29′, carrying as many as 20,000 flowers, producing upwards of a million seeds. This species typically takes up 40 to 100 years to bloom and, being monocarpic, like most Bromeliads, then dies. The UC Berkeley Botanical Garden have grown this from seed blooming in 1986, the first such event in the world away from its native range, and then again in late summer of 2014 and 2018. Mysteriously their flowering came at 28 years.
This particular species is considered endangered and is threatened by fire across its home range which is used by local populations to ‘improve’ pasture land. The ‘million’ seeds produced at flowering by a single plant may seem sufficient to assure this plants survival across the Altiplano, but recall that this production is minimized by the ‘events’ relative rarity, the long cycle between germination and flowering. Pasturing livestock on limited land puts heavy pressure on it and as Puya species are not palatable and dealing with this species’ physical structure would be a formidable undertaking with limited power equipment, fire would seem to be the most effective strategy eliminating this ‘pest’ from the pasture. Farming often has more immediate goals directly opposed to those of the ecologists. This conflict will likely be exacerbated as climate change continues to alter precipitation reducing it overall and effecting the frequency and intensity of rain events and snow in the framing mountains. Drought and temperature increases are already effecting the Andes, and those ares which are already arid have less margin for such reductions without producing serious consequences for both agriculture and the survival of native species. The seed from endangered plants, and seed is the only way to propagate this plant, as it does not form offsets, is protected and shared only with those approved to study it or to grow on for restoration projects. It would be interesting to see if the Berkeley garden has more of these growing out on its grounds, a location considerably easier to visit than its home range. It is extremely unlikely that you will find one to grow on in your own garden.
Puya mirabilis (subgenus puyopsis)
Obviously then, all of the other species are smaller. Puya mirabilis, its rosette only 10”-12” tall, which I grow in a pot, is reportedly the quickest to bloom… mine has begun after having purchased it in a 4” pot in Oct. ’15. This plant appears more ‘lush’ somewhat softer and greener than its cousins above. The flowers are yet to emerge, so going by Annie’s Annuals description they are, “elegant, flaring, lime green bells held in fuzzy purple-grey calyxes”. Like all monocots their flowers are three petaled, though these are much larger and more prominent than others that I’ve seen and will be quite prominently displayed on 3’ stems. This too is a Bolivian species and is very drought tolerant, deer resistant and loved by hummingbirds when in bloom. Hardy down to 20ºF, mine will be forever in a pot which suits its stature well. Of all of the Puya I’ve grown and/or researched, this might be the ‘best’ one to grow for the mild temperate gardener: relatively quick to flower, pretty flowers, a very manageable plant for a pot, drought tolerant/mediterranean and perhaps the ‘kindest’, least aggressive foliage of the genus, I’ll give it a 2 on the scale.
Here’s a link to a later post of my Puya mirabilis while I followed it through its blooming cycle.
Puya venusta (subgenus puyopsis)
Puya venusta…this is a sad story. I bought this one from Sean Hogan that he’d identified as the ‘pink stemmed form’ on the label. This is a beautiful, almost white leaved plant, with stiffly arcing, channeled leaves with the typical recurved hooks you would expect running continuously along their margins…but they are in scale with the plant’s stature, of up to 40” tall the offsetting rosettes can spread to 5′ across. The flowers rise up about 3′ above the rosette. Native to arid mountainous areas of central Chile and Argentina were it grows on sites typically with a northerly aspect, generally out of full direct sun. It tends to inhabit areas that don’t freeze though it is thought to be safe into zn 9. Some growers, like Ian Barclay of Desert Northwest, write that they expect this to be hardy down into the low 20’sF. Annie’s says that it should be tough down to 20ºF. Some rate it as a zn9 plant. This selection was collected west of Tafi del Valle, in Argentina at 11,800’, Sean is generally very good with his collection data and this emboldened me…not always a good thing. After growing it for a few years in a pot that I would protect from freezing weather by shuttling it down to my lighted basement, I decided to try it outdoors, in the ground. I planted it in my south facing parking strip at the base of an established Trachycarpus fortuneii, 12’ or better tall, my thinking going somewhere along the lines that the tree would protect it from radiant heat loss and shed some of our winter precipitation away. It did this. The tree’s roots also helped keep the winter soil drier as well. This seemed to work well for its first two winters, both of them mild, but it was a mistake. This last winter was very wet, with 57″ accumulated during the rain year (which is measured from Oct. 1, the beginning of our wet season, through Sept. 30) by the onset of our dry summer season, 167% of normal. Combine that with the two, severe for us, cold snaps, one in early December and one a month later, dropping to as low as 15ºF, tormenting us and our gardens with freezing and near freezing temperatures from early December throughout much of January … this plant perished.
Puya dyckioides (subgenus puyopsis)
Puya dyckioides, another Andean Puya from Bolivia and NW Argentinia, has been successful for me outdoors. It’s been growing on my south facing retaining wall, protected by an overhanging Oleander. It has formed a substantial clump, newer offsets crowding out older, blooming consistently over the last several years. It is relatively easy to work in and around as the leaves are neither overly stiff nor are they heavily ‘armed’. You still should be careful and deliberate around it, but the risk of injury on a scale from vicious and unavoidable, as a 10, down to ‘you have to try to inflict injury upon yourself’ as a 1, I’d put in the 2-3 range. The plant has an overall softer, ‘grass like’, appearance. The marginal spines are tiny. Still, while grooming it earlier this summer, reaching in and pulling away the older dead rosettes, my unprotected forearms received many tiny and irritating little jabs, that brought up no blood, but left my arm looking as if it were covered with tiny ‘hives’ and itchy. These take 6-7 years to reach blooming size and I believe this will be my sixth summer with bloom. If your sun is too intense, as my site would be for this plant, offer it some shade.
I’ve never lost this plant. Tony Avent at Plant Delights rates it a zn 8a saying that at 7ºF, for him in Raleigh, N.C., it suffered only some leaf burn, which it grew out of quickly. My plant is another acquisition for Sean at Cistus who originally sold it under a collection number. I grew it for a couple years in a pot before setting it out on my retaining wall in its present location. This selection came from the mountains, west of Tafi del Valle, Argentina, about 26º 46′ south latitude, which is equivalent to roughly the state of Sonora, Mexico, in the northern hemisphere, growing from a cliff side at 11,800′. It’s native elevation cools its site requirements. The Valley below is grassland and receives less than 20″ of rain annually, primarily in their summer. This doesn’t seem to be a likely candidate for a Portland garden, but where there is a will, a way can often be found. I would like to say that I chose the perfect spot for this intentionally…but, luck and opportunity played a role. My concrete retaining wall probably help moderates the lows a bit and my site is shielded from the damaging east, Gorge, winter winds. The overhanging Oleander protects it from the most intense summer heat while also sucking up some of our winter wet. It does get some water in summer from a drip system that I run irregularly.
This plant fits more into the category of ‘interesting oddity’ than cool specimen. It borders my front sidewalk yet almost no one ever comments on it, unless I point it out to them…except for my fellow plant geeks who rarely miss a thing. It is in the Puyopsis subgenus so it doesn’t have the sterile side branching along its inflorescence, but it does possess an almost ‘club like’, heavy stem or peduncle quite unlike many of the other species. It is the heavy stem that displays the pink color in its bracts, each holding its single dark teal colored flower.
Puya berteroniana (subgenus puya)
Puya berteroniana, possesses more than promise for our region, it has demonstrated some durability here already. I got two plants a couple of years ago from my friend Mike Remmick. Mike’s greenhouse is in the hills south of McMinnville, OR. I’ve come out and helped him a couple of times cleaning up and reorganizing it in late Spring and noticed his collection of Puya spp.. Mike has visited South America on plant trips and like’s this genus…so he planted out those that he thought might be tough enough for our typical winters, temperature wise, and experimented at his previous home in McMinnville planting them in the garden…this one survived and performed. He has since moved into SE Portland and Puya berteroniana has found its way out into the hell-strip, not far from my own garden in the same soil type, the typical Willamette Valley Lattourelle loam with minimal amendment.
I’m lifting the following from Annie’s Annuals website…who wouldn’t want to grow this!
“One of the most astonishingly beautiful plants to grace our planet direct from Chile! Spectacular, 2-3’ long and 1’ across pineapple-y shaped spikes are densely studded with 1.5” waxy, metallic blooms of the most unearthly emerald-turquoise. Contrasted by bright orange stamens and filled with blue syrupy nectar, they’re a bonanza for birdies who perch on sterile, horizontal stems. To 6-10’ tall in bloom (year 6-8). Spreading slowly by offshoots, spiny 3’ silvery rosettes work well as a security barrier. Can also be grown in a container! Deer resistant, plant in well-drained soil with occasional Summer water. Hardy to 20°F.
Check out the description on the Strange and Wonderful Things site, the creator of which waxes on even more eloquently, also giving me some doubt and questions as to where to plant this, as over time they can offset and form extensive colonies…dividing this in the ground, hemmed in by my retaining wall, would make this a very challenging, and likely bloody affair…if it performs in a similar manner!
This Puya is endemic to the mediterranean climate of the coastal and Andean mountains of central Chile, sharing some its lower range with Puya chilensis which is more limited to the lower coastal mountains. You can find P. berteroniana between 500m (1,600′) and 2,000m (6,500′) where it experiences a dry summer period, much like ours, of 3-5 months, but can go much drier tolerating as much as 10 months of drought. It’s precipitation ranges from as little as 4″ annually, but more commonly between 16″- 32″. Chilean experts rate it hardy to -5ºC (23ºF), but again, Mike has grown it successfully in McMinnville, USDA 8a, 20ºF. I did find another site that claimed success down to 15ºF! Most Puya are thought to be intolerant of freezing temperatures. This is a full sun plant and is typically found on sloping sites, often with coarse mineral soils. Like so many other plants, given its elevational range, I would suspect that its performance for us would vary with its provenance.
Mike collected this from the Rio Teno area at approximately 35ºS latitude around 5,900′ elevation.
Having lost smaller sized plants that he had planted out, Mike suggests waiting until your plant’s rosette is around 2′ across. He’s found that larger plants tend to be more successful. I’ve grown my two plants into crowded 2gal size, one of which I planted on my south facing retaining wall, this last Fall, in a spot where I’d just removed a Brown Turkey Fig tree that had become an out of scale, almost unharvestable, beast, even with my heavy pruning of it. Its a masonry wall backed with rubble so the drainage is relatively fast, absorbing heat from the sun along its south face. The new Puya shares the bed with other plants like the blue form of the Mediterranean Fan Palm, Chaemerops humilis var. cerifera, an Oleander, Nerium x ‘Hardy Red’, a prostrate Rosemary, Zauschneria, Penstemon, Caesalpinia gilliseii, my well established Puya dyckioides, described above and others. It will get a little shade here from a Chinese Fan Palm growing to the south of it…but I’m hoping it will do okay. As noted above these take 6-8 years to bloom, but then become perennial bloomers…this is no one and done performer.
Before I leave this species, I must mention that yes, it does register well into the danger region on the ferocity scale, being ever so slightly less fearsome than Puya chilensis, I’ll give it an 8+…so, if you choose to try this, be forewarned!
I am tempted to try P. venusta again and am intrigued by P. alpestris, both are on an extensive ‘wish list’, as they don’t get too huge, can take some minor freezing, have amazing flowers so I won’t need dedicated full time indoor space for them all winter, so for the most part they can stay out on the covered porch dry. These species feature, colorful and spiky inflorescences….and yes, those aggressive recurved marginal spines as well.