Puya mirabilis: Flowering, Place and Choice, The Wonder and Magic of Gardening

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Sunday night our son and his girl friend came over for dinner on the deck.  The week long heat wave had passed and it was another very comfortable evening outside.  They had been at the beach attending a wedding the day before, Julie’s birthday.  When they first arrived, because I can be a bit obsessive, I noticed that the still tightly ‘rolled’ petals in the extending flowers on my Puya mirabilis were ever so slightly beginning to curl back and open.  It was one of those times I wished I had a camera to set up to do a time lapse series, but I don’t.  Regardless, within 2 hours the five lowest flowers were completely opened with stamen and styles fully extended beyond the corolla.

This is a plant that you stay home for.  Cancel or delay your vacation when blooming approaches, plan around it..its that nice…and brief.  Each flower is relatively short lived.  The initial opening included five flowers with nine more to follow.  I have it growing in a 9” dia. pot.  I bought this last spring in a 4” gage pot. I transplanted it into a 1 gal.  This gave it plenty of room and simplifies drainage and, because it is a zn 9 plant, allowed me to safely tuck it away when ever temperatures threatened to drop below 25ºF from its ‘normal’ winter location on the porch under the roof, which happened a few times last winter.  I moved it in and out throughout the winter. Once spring was firmly established I moved it into its current pot.  This is probably the quickest Puya to flower, some of these can take quite a few years to mature.  At some point after its finished flowering I’ll divide it, its 8 pups will more than make up for their monocarpic dearly departed.

It’s flowering stem, peduncle, was over a foot tall, sticking up somewhat above the rosette of foliage, before I noticed it July 21.  It quickly approached its maximum height of around 45”, with its buds riding tightly together near the terminal for most of the extension, skinny bracts spiraling below much like the very similar structure of an Agave peduncle.  It was Aug. 4 before the lowest bud settled and the flowering terminal spaced out each of the expanding buds over the next several days.

Over this next week, to the 11th, the buds did some serious elongation reaching 2 1/4” in length.  That evening, the enclosing sepals began to ever so slightly open.  On the 13th, just before 4:00pm, the tightly rolled green petals were protruding a good 1 1/2” beyond the sepals….By 7:00 they were separating.  By 8:00pm, in the failing light, they were nearly fully open!  24 hours later the next two flowers were reflexing open, each 4 1/2” long measured from the base of the flower where the pedicel attaches.

I spent much of the next day periodically checking on their progress or sitting out on the deck, it was a beautiful day peaking in the low 70’s, reading about flowering in genus Puya with an eye out for bees and our resident Annas Hummingbird. I haven’t seen any activity, although I do hear the sporadic ‘stic stic stic’ of them above.  This plant is far from its ‘home’ territory and the pollinators that ‘know’ it.  The anthers and stigma are physically very close to each other, the anthers dehisced exposing their pollen, and I wonder if the flowers are capable of ‘selfing’.  Across its home ranges many Puya are bird pollinated with insects being more incidental.  The flowers are nectar producers, the volume of nectar, the concentration of sugars in them and even the kind of sugars, varying between species.  Studies have shown that these nectar factors are important in attracting particular species as pollinators.  Additionally some species have inflorescences with sterile apexes on ‘branches’ spaced radially along the main stem, providing perching for passerine/non-hovering birds.  This latter group of Puya, are part of a small group, the subgenus Puya, and are visited primarily by passerine/non-hovering birds.  This subg. also tends to produce large quantities of nectar with low sugar concentration which tend to include mostly sugars other than sucrose as these birds don’t possess the stomach enzymes that can digest this.  Hummingbirds tend to dominate those Puya spp. having low volume/ high concentration nectars and though they prefer other sugars will dine on those high in sucrose.  Hummingbirds depend on a diet that is higher energy than other birds, while the lower sugar/large volume nectars better meet the water needs of most passerine bird species especially in the arid climates that these plants occupy.  Passerine birds, perching birds, which visit Puya also depend on a variety of other food sources whereas hummingbirds are more clearly nectarivores.  For some of these passerine birds at least, the nectar is primarily a water source.  There is a certain degree of coevolution that occurs between species like this, each shaping  the development of the other over time.  For more on this see: “Morphology, nectar characteristics and avian pollinators in five Andean Puya species (Bromeliaceae)”

Puya mirabilis, is a member of the subg. Puyopsis, those species with high concentration, low volume nectar without the sterile apex, or branching on the inflorescence.  These are hummingbird plants…so, I continue to sit on the deck waiting for one of our Annas to figure it out.

Last year the plant that most grabbed and hung on to my attention was my Agave ‘Sharkskin’ as after 18 years of patient growth, it flowered and later succumbed.  While much less physically imposing and much more precocious in flowering it has been this Puya mirabilis that has captivated me this summer.  I will continue to dote on it, learning what I can following it through the seed development process and division to follow.

Hmmm.  It’s now 36 hours since the first five flowers opened….Now they are clearly in decline!  The petals are rolling in on themselves, while the anthers still hang on to what looks like most of their pollen!

I finished watering in the garden and treated a few plants for Root Weevil.  Adult activity has been obvious for several weeks, their notching along the leaf margins of members of the Saxifrage family and on a few other plants like Trycertis that they are drawn to.  I’ve been slow to respond this year.  Later, I was sitting out on the deck reading, this time fiction, when at the end of a chapter, my eyes focused on the Puya again and I started thinking about our human bias which drives so much of our plant selection decisions and our hybridizing.  Our plant selection for our gardens and landscapes are strongly effected by our bias.  Much like we tend to favor mega-fauna, primarily mammalian, and are less likely to romanticize, or even think about, the vast majority of creatures that live below our notice, living beneath the water surface beyond our view, burrowing in the soil or the bodies of other species. we ignore most of the plant world.  Most plants are beneath our notice.  They are taken for granted and serve as a backdrop to our lives.  It made me think of what stage decorators do on TV and movie productions, stuffing greenery into a scene, with little regard for botanical accuracy, to achieve an effect, beyond the range of the camera’s focus.  Perusing most plant catalogs it becomes quickly evident, that once we have filtered out those plants that might be nigh impossible to grow in our gardens, most of the rest, sans trees, are attracted to a kind of ‘mega-flowered flora’, plants with flowers that make the biggest impact.  The most common include several attributes, relatively large size, bold color, dominating scent and a longevity that approaches permanence to the maximum degree possible, longevity in terms of an individual flower, or of the plant’s ability to produce a nearly continuous production of bloom.  We find these plants more attractive, more desirable, and the industry serves them up to us.  The plants at the opposite ends of these scales, those more difficult to grow, with smaller, less attractive scent and less striking colors and forms, flowers that are short lived and plants that are shy to flower…these characteristics add up and become reasons to discourage our use of them.

I bring this up because Puya mirabilis, though its flowers are generously sized and elegant in form, are individually short lived and are produced on an inflorescence that lasts less than a week.  The rosette that produces it is monocarpic producing just one stem before it dies.  This may seem a recipe for failure, but plants don’t grow for millions of years because they lack what it takes to survive.  Growing it as a potted specimen then takes commitment.  If it were possible to grow in the ground here, it could bulk up over time with many pups sending up multiple scapes, over a period, I’m guessing, of several weeks.  In a pot, however, it’s one and done. As gardeners we have only so much time and space for plants, so we are selective.  On the plus side this is a no fuss plant.

Puya species are all relatively young having developed with the rise of the Andes 15-30 million years ago.  Like any species they’ve adapted to their region to the peculiarities of their own place.  They are successful plants.  Their particular blend of genes, works, whether we like them or not. Their limited ability to produce seed is sufficient to keep the species vital while it depends largely on its vegetative abilities to bolster its numbers.  It is a strategy pursued by other species like Quaking Aspen that have been found to form colonies many acres across from a single organism. While it may seem an extravagant expenditure of energy for a relatively small plant to produce this few and short-lived of flowers, its proof as a strategy is in its existence in its native landscape unassisted.  This has amongst the largest flowers of any Puya species.  It readily offsets and has a short life cycle, new pups flowering and dying the summer following their initial formation.  Presumably, seedlings would take somewhat longer.  Our choosing plants for our gardens has little to do with their place and value in its native landscape.

Hybridizers might look at the flowers of this species and begin crossing and back crossing with others trying to develop progeny that retain the flower size and precociousness, while adding repeat blooming and more long lived blooms and in the process, cause them to lose some of the characteristics that have lead to their success. (This isn’t entirely fair as many hybridizers are also very focused on disease resistance.  Growth habit, including form, dwarf size, branching, leaf color and form, are also considered, as well as developing plants that are better able to survive in different regions.)  Our bias causes us to often fail to recognize the value of the organisms around us.  Our hybrids, conceived for our own purposes may only be suited secondarily for survival out in the world while survival is the ultimate driver isn the success of species in nature.

Our impatience with nature, our lack of awareness regarding its intricacies and complexities contributes to the blindness that we share regarding our landscapes nearer home.  Eager to create our own backyard habitats and bird sanctuaries, in our sincere attempts to ‘heal mother nature’ and lessen our own negative impact on the landscape, we are prone to visiting our local garden centers and buying from their offered dozen or so native species, ignorant of the many hundreds of others not on the shelf and thoughtfully lay them out.  Some of these are offered because of their ‘durability’, their ability to adapt to a wide range of degraded sites, others fall more closely into the category of ‘mega flower flora’ and their appropriateness for our sites may not have been realistically assessed.  Our own regional flora can be every bit as demanding as exotics from across the planet.  It is incumbent upon us to do our homework whether we are seeking plants for a home project or considering ‘developing’ a piece of land.  It is important to understand what we are sacrificing.  Plants are not interchangeable.  They can have very specific requirements that include the abiotic conditions we are more used to considering, but also the biotic conditions, the communities within which they live in close association.

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The following Saturday morning, 36 hours shy of a full week since first bloom opening…not the most ‘tidy’ blooming plant. The last flower is extending while all of those below continue to dry. Even the the oldest flowers here still have pollen on their anthers though their filaments are flaccid and the stigmas look well passed their receptive stage. A short accelerated flowering. Will they form seed?

Growing exotic plants has pushed me to better understand the plants that I choose to grow.  One of the first plants that I ever killed out right was a Calypso bulbosa, one of our gorgeous native orchids.  I grew it because I wanted it.  I planted it in the shade of a tree in Oregon City and watched it die.  Native plants aren’t a ‘no brainer’ for the gardener.  The relative lack of species availability regarding native plants should tell us two things; one, that the gardening public is not demanding much more than is offered, and, second, that many, if not most of our native plants, can be quite specific in their growing requirements.  Very few Oregon native plants can be successful wherever we might choose to plant them in the state without a great deal of intervention on our part.  Plants will always require that gardeners understand their sites and the plants they choose to grow.  When we begin to do this we begin to notice that the flora of other regions may be well adapted to the conditions in our gardens and we can decide what kind of modifications to it we are willing to make to achieve success or what accommodations, above and beyond, providing winter protection or taking the extraordinary step of propagating it to assure we have plants for the following growing season. we will make to meet the plant’s needs.

Growing plants like Puya mirabilis gives us the opportunity to see and experience it, something we would otherwise never have the chance to do without traveling thousands of miles.  It helps us appreciate the uniqueness of our own flora, too much of it threatened and even critically endangered.  It teaches us more of the incredible diversity of the world’s flora and how intimately matched to local and regional climates they are.  In short it helps awaken us to the world and should give us pause before we decide to bulldoze and develop every piece of land available as we spread out imposing the painfully sad and limited idea of landscape that our ‘consumer’ western culture would have us all accept.  It is not just the Bolivian Andes or the mattoral of Chile that we should reconsider, not the Amazonian jungle being burned and converted to ranch lands, nor the forests of Borneo that are being converted to profitable commercial plantations, but our own backyards and regional landscapes.  We have forever altered the prairies and Oak savannah of the Willamette Valley, shouldn’t we be asking ourselves whether it has been ‘worth’ it?  Whether we should continue the same pattern of ceaseless development?  As we continue spreading across the planet we also continue transforming/destroying the many naturally occurring landscapes and their plant communities, and, in the process, lose an increasing number of species, species with too few advocates.  The many millions of years of adaptation and speciation has been astonishingly successful resulting in the diverse planet we inherited prior to the Industrial Age and the expansion it has enabled…until now.  Now, we with our own biases and values, regularly make life and death decisions based solely on a plant, place or animal’s utility to us or the relative fickleness of fashion.  Plants and animals that are irreplaceable, fulfill functions in their landscapes/communities that, sadly, too often we can only guess at.  We are compromising the health of the entire planet.  This is not just a problem for ‘them’ to take care of, it is most certainly our responsibility as well, because it is happening literally in our own backyards, fence lines, road medians, vacant properties and more.  The ‘solution’ does not lie in the protection of distant exotic landscapes alone, those are after all ‘just’ the backyards of other people much like ourselves, but upon the ones that we are in direct relationship with.  Most Oregonians have no idea what has been lost and what is at risk.  Gardening is not just an opportunity to make something ‘pretty’, it is a window through which we can better understand the world within which we live…if we choose to look.

Puya mirabilis: Phyllotaxy refers to the arrangement of leaves, bracts and flowers along a stem.  In monocots, like Bromeliads, which includes Puya spp., the pattern is radial, spiraling around the stem as you ascend.  1:2:5, is for P. mirabilis.  As you ascend the stem you will make two complete revolutions, rotating counter-clockwise; before the first ‘alignment’, when the fifth leaf, bract or flower, aligns perfectly with one below it; Every fifth is so aligned; stem/peduncle 45”; pedicel 3/8”; total flowers 14; sepal 3 – 2 1/4” long; petals 3 – approx. 4” long; total flower length 4”; flower width across the corolla, 3 1/4”; 6 stamen, 1 style; petals extend fully in closed position and then opened in the evening over a period of about 2 hrs; stamen and style are exserted beyond the corolla tube; the lowest 5 flowers opened almost simultaneously; by the next morning the next two have extended their still rolled petals over an inch; pollinated by hummingbirds; monocarpic; 8 pups; offsets readily; quickest Puya to flower, bought last spring in a 4” gage pot, blooming mid-August the next year in a 9” pot growing in a pumice-y well drained mix. Watered once a week or less during the warm season; left mostly dry in winter; Spent the coldest portion of winter in my cool lighted basement; hardy to zn 9, 20-25ºF.

An article on genus Puya from Dave’s Garden.

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