</p> So begins a poem by the great 20th Century French Poet Guillaume Apollinaire (see below). I hasten to point out that the plants depicted (blooming right now at Denver Botanic Gardens) are technically not heathers (Calluna vul</em>garis--a single species from Northern Europe) but heath (Erica</em>--an astronomically larger group with hundreds of species mostly in South Africa). They're all very closely related, so let's not get too technical with common names, now. The pictured species from central and eastern Europe (Erica carnea</em>) is notable for many reasons: it is by far the hardiest of heathers, the one that loves limy soils and thrives in Colorado with only a modicum of supplemental irrigation: and best of all it blooms much of the late winter and spring. </p> </p> Erica carnea 'Vivelli' in Rock Alpine Garden</p> I've been disappointed in a few plants this spring: some of the bulbs have passed too quickly, and with our polar cold (-22F at my house) there has been winter damage, albeit far less than I feared. But the winter heaths are simply spectacular. I am distressed that plants that thrive so manifestly, that we have shown off so superbly at Denver Botanic Gardens for so many decades have literally languished in undeserved and pitiful obscurity, while Box Stores and even our noble local garden centers stock so many plants (how shall I put it tactfully?) of lesser merit. Considerably</strong> lesser</em> merit....ahem!</p> Fear not! You can buy these from many sources mail order! A great way to get plants, by the way (and with Paypal and the new convenient computer programs, you can be bankrupt in no time at all!). If you didn't get it, I linked the very best source subliminally at the start of this paragraph...</p> Now let's get back to literature: clear your throat, lean back and proclaim (in your very best French):</p> L’adieu </strong> </p> J'ai cueilli ce brin de bruyère L'automne est morte souviens-t'en Nous ne nous verrons plus sur terre Odeur du temps Brin de bruyère Et souviens-toi que je t'attends</p> Farewell</strong></p> I have plucked this sprig of heather / Remember herein that autumn has died / We shall never again see one another / Whiff of that time--a sprig of heather / And I still wait for you--remember! </p> Guillaume Apollinaire</p> </p>
</p> Catalogs call them "minor bulbs"--those little gems that brighten up our gardens in late winter. I am frankly astounded that you see so few of these in Denver gardens (or anywhere in the Rocky Mountain region). For any number of geobotanical reasons, there are only a very small number of early spring ephemerals in our native flora. But the Mediterranean region and Central Asia teem with extraordinary flowers that bloom as snows melt. These seem to grow here with real gusto. Crocuses, snowdrops, Cyclamen coum</em> and reticulate irises are all winter's jewels or else spring's earliest heralds. And there are many more as well, but the tiny grape hyacinth, Muscari azureum</em>, holds a special place in my affections. </p> Mention grape hyacinth, and many gardeners groan: the commonly grown Muscari armeniacum</em> or M. neglectum</em> thrive here all right: they can be downright pesky in the garden, producing vast sheaths of messy foliage in fall that singes by spring and doesn't quite justify their gloomy purple blue clusters that come a little too late (when everything else is blooming too).</p> There are a number of equally prolific grape hyacinths with more winning traits, and the first of these is this tiny blue marvel that usually opens its first blossoms at ground level in February. March, however, is its time of glory: right now the dry borders in my garden have wide swaths of azure blue, like the little pool of color you can see below.</p> </dt> Muscari azureum</dd> </dl> It is prolific, but please don't summon the invasive police! In this case, one can never seem to have enough of this good thing. It sprinkles my borders, my rock garden, it seems to pop up somewhere new every year. Of course, I have been known to gather its seeds in May and scatter them around rather enthusiastically. This little gem is above ground only a few weeks, and at the time of year our gardens are their most austere and need that little extra kick. And tiny though it is, its piercing blue is welcome. I first came to know this plant in the garden of the late T. Paul Maslin, an eminent biologist who taught at the University of Colorado in Boulder. Paul passed away in 1984. He was my near neighbor growing up with the most beautiful garden in Boulder (maybe in the state). He became my mentor and best friend. He loved this bulb (then known as Hyacinthus azureus</em>) which grew everywhere in his garden too. In fact, my plants trace their origins to Paul. In the later 20th century, Botanists called this bulb Hyacinthella azurea</em>, so the Latin specific epithet has progressed from masculine to feminine and is now neuter! No matter what it's name or sex may be, this is a bulb I wouldn't want to live without. Every day in March I go out and admire it here and there, and think of the vast swaths of Anatolia that it graces in nature (where, no doubt, some of my ancestors a millenium ago admired it too), and of my wonderful friend, Paul. I look forward to the day it carpets much of my half acre with azure scatterugs of sparkling blue. One could have much worse predilections, I'm sure you would agree!</p>
This past fall (as if overnight) a conflagration of spectacular red trees glowed for weeks all over Denver...friends and members of the Gardens would ask me what are</strong> those fabulous maples? They are very appropriately named 'Autumn Blaze', a hybrid of silver maple (Acer saccharinum</em>) and red maple (Acer rubrum</em>), combining the spectacular fall color of the latter with the adaptability and vigor of the first. With perhaps a little added hybrid vigor tossed in as well. Considering the plant was only introduced into cultivation in 1980, its ubiquity and abundance in cities across America is sobering. Tree experts are concerned that as these mature they are apt to develop the same breakage problems as the parents (possibly more due to rapid growth), and likewise share the sensitivity to alkaline soil that often turn both parents chlorotic in midsummer. Everyone wants a tree that grows super fast, forgetting that this often means the same tree can grow massive in short order, and is often prone to spectacular and expensive breakage. No one really knows how big 'Autumn Blaze' will grow in Colorado, nor really how brittle it will truly be in old age. Perhaps this is a plant best enjoyed in your neighbor's</strong></em> garden? What an amazing impact, however, the bright red has all over our region, especially combined with the brilliant purple tones of 'Autumn Purple' ash (Fraxinus americana</em>): they have done much to enrich the color palette of our predominately yellow fall color. The ash, however, also needs lots of water to do well and has a host of present and potential pest problems! Coloradoans like to think every tree is wonderful on our windy steppe. I caution friends to stick with tried and true trees in their own gardens. There is a whole list of Index expuragoria</em> when it comes to some arborists: either they are excessively prone to disease and pests, or subject to breakage or too water demanding. I shall take a look at several of these naughty trees...but it is good to remember that if a tree may not be ideal in your garden, it doesn't mean that it would not be suitable in a park or other large site. I for one delight in the spectacle that 'Autumn Blaze' has brought to our city. But you will not see one in my garden!</p>
</dt> Orostachys iwarenge</dd> </dl> This time of year there is no end of vibrant, glorious color at Denver Botanic Gardens. May I remind you that green is also a color? Few plants exemplify the paradox that gardens are not just about showy flowers than these modest succulents from East Asia: Orostachys</em> are closely allied to Sedum</em> (and have been classified as such) although they suggest hens and chicks (Sempervivum</em>) more to my eyes. The flowers are actually miniscule...but everyone loves and appreciates these accommodating succulents. I find they grow best on shallow soils or in pots: quite a number of species and hybrids will be coming into bloom over the next month or so. At DBG check for them in the Rock Alpine Garden (although finding them in that treasure trove of gems could be a challenge!)</p> </dt> Orostachys spinosa in a trough</dd> </dl> You know you have succeeded when you are copied: this picture (or something like it) has shown up in books, in nursery catalogues, on advertising flyers and in other people's talks: people just love the way the gray trough seems to morph into these gnarly, symmetrical globules of succulence. So they steal my image and use it without permission...(I admit I am flattered...). Where is the flashy red or yellow? You do not need garish color to delight. When you have seen this wondeful little plant growing literally by the millions across the mountains and steppes of Kazakhstan and Mongolia, a trough like this is hopelessly evocative. Who needs petunias? OK, OK, before you get all huffy, I confess I like petunias too, and grow quite a few (albeit mostly in containers as well...)</p> Perhaps the most widespread Orostachys</em> in cultivation is this munchkin from Japan (I believe) which has been sold over the years under a plethora of names. It seems to be settling down to this epithet, although one still encounters O. furusei</em> in some nurseries. If you can make it happy (which is not hard: part shade or sun on shallow soil in a rock garden or container) it will form wide masses of tiny pagodas that are irresistibly cute this time of year...Here it is growing on top of a rock in the Snyder's awesome Littleton garden, proving (irrefutably), once and for all, that less is more!</p>
</dt> Himalayan foxtail lilies in the Perennial Walk</dd> </dl> </dt> Foxtail lily hybrids in the Ornamental Grasses garden</dd> </dl> If you've been to Denver Botanic Gardens in the last month you can hardly have missed them: no, not the Henry Moore sculptures (albeit they stand out!), I'm talking about foxtail lilies: Eremurus. </em>These stand out (and stand up!) in a dozen gardens: bristling exclamation points that are impossible to miss. </em>The literal translation of this Greek-derived scientific name is "Desert tail", which isn't quite accurate. Foxtail lilies are sentinels of the true steppe of Eurasia, growing from Anatolia in the west all the way to Mongolia in the east. They are not found on true desert so much as grassy prairie and montane meadows. Mike Bone and I saw them in the Tian Shan mountains above Almaty last summer and on the foothills of the Altai mountains of Kazakhstan (high points of our trip last year). The climate of Central Asian steppe is the exact equivalent of ours (we are "homeoclimatic") so it's hardly surprising that Eremurus</em> do so well in Colorado. I would be hard put to decide if I like the towering white Himalayan eremurus (Eremurus himalaicus</em>) in the Perennial Walk more than the even taller Eremurus robustus</em> blooming there now....or the yellow spires of Eremurus stenophyllus</em> filling PlantAsia's steppe garden as we speak...or maybe the many burnished and brassy hybrids in gold, nearly brown and brilliant orange that make the Ornamental Grasses garden riveting this time of year, or encircle the annual test gardens...</p> These inspiring spires and towering turrets of bloom practically brand Denver Botanic Gardens, making it seem like foxtail lily botanic gardens for a month or so in early summer. I would be envious if I hadn't gone out and counted nearly a seventy foxtail lily stalks in my very own garden that have bloomed so far this year. One can never have enough of a good thing, right?</p>
</p> Managing the environment versus managing people surely should be very different... or are they? Lately I have been challenged to make such an analogy and found it surprisingly compelling. Through the course of my 15 years studying invasive species biology and restoration ecology, as well as learning from the horticulturists here at Denver Botanic Gardens, I have come to the conclusion that there is no such thing as a bad plant... but that certainly there is plant "behavior" that we may deem harmful, such as when tamarisk trees dominate a riverbank to such an extent that nothing else can possibly grow.</p> Are tamarisk inherently "bad"? Of course not: they play an important role in their native ecosystems in Eurasia, and as it turns out, can also provide habitat for some birds and fulfill other ecosystem services in "invaded" ranges. That is, they can have both "good" and "bad" behavior. Which they do depends on the interaction of the tree with its environment. </p> Put tamarisk seeds in an area with lots of water where desirable native trees have been displaced through poor management or other causes, and they will dominate and further degrade the ecosystem through salt deposits and increased fire frequency. Alternatively, if the land is well managed and desirable species are doing well, tamarisk will not be invasive and individual trees can actually be a benefit to the overall ecosystem. </p> You may already see where this analogy is going.... I believe strongly that there is no such thing as an inherently "good" or "bad" person/employee/team member. However, any individual has the capacity to behave poorly and/or not contribute; it is up to an effective leader to make sure that A) the environment is managed well to promote "good" behavior and B) that the right people are in the right positions (i.e. they are doing jobs best suited to their skill sets and interests). </p> According to Jim Collins (of "From Good to Great"), one of the features of highly successful organizations and businesses is that they prioritize personnel decisions. This may be simple, but it certainly isn't easy. In the last couple years, we have seen Denver Botanic Gardens flourish in new and exciting ways; it is certainly a testament to this principle. Every new hire here thrills me because I know that the environment here promotes excellence, and that we work hard to put the right people into the right positions. We will be losing one of our finest leaders soon; Betsy Cheroutes, director of development ,is beginning a much deserved retirement. I have learned much about leadership from her and will dearly miss being able to pop in her office for a quick bit of advice. However, I know to anticipate great things from her successor in this positive environment. The tamarisk trees taught me that.</p> This blog post was written by Anna Sher, Ph.D.</em>, adjunct researcher and former director of the Research & Conservation Department at Denver Botanic Gardens.</em></p>
This time of year, while rather bleak and cold outside, really gets me excited for what's growing on in the Boettcher Memorial Tropical Conservatory. As I was watering this morning, I could not take my eyes off of the absolutely beautiful Brownea ariza</em>. The big, bold, red flowers always seem to slow time down for a few minutes and remind me of how much beauty really exists in my "office." Brownea</em> is a member of the large Fabaceae, or bean, family. The genus itself is not a particularly large genus, with about 30 species. Brownea ariza</em> is a smaller tree, and sometimes can take on the form of a large shrub. All members of the genus are native to Tropical South America. Brownea</em>, as well as many other members of the family, put forth new leaves in a very interesting and unique way. The young, tender leaves emerge looking rotten or diseased and as the leaves mature, they grow into their "normal" state, this most likely occurs to prevent predation upon the new growth. Brownea ariza</em> also exhibits cauliflory, which means that the plant flowers and fruits from its main woody stems or trunk rather than from new growth. A few other famous cauliflorous plants are: Theobroma cacao</em> or chocolate, Callistemon</em> or bottlebrush, and Cercis</em> or redbuds. Because of the cauliflorous flowering habit, the large flowers are very hard to miss. It's right around this time every year that our Brownea</em> really starts to push out many blooms, and this year is no exception. The plant is packed with them right now with quite a few of them right around eye-level. The flowers, unfortunately, only last a couple of days, so be sure to come in and enjoy them while they're here in force. The Brownea ariza</em> is located just to the left of the fork in the path after entering the Boettcher Tropical Conservatory through the main doors, you can't miss it. (And of course, keep an eye out for all of the gorgeous blooming bromeliads!) There are two good vantage points for enjoying the Brownea ariza</em>, one being directly in front of the tree from ground level, the other being from the balcony just above the main entrance to the conservatory near the Green Roof Exhibit. I also feel obligated to point out that the newly planted Brugmansia sanguinea</em> has a few buds, so check that out while you're here too! Hopefully I'll see you soon, as you absolutely don't want to miss this fantastic display of winter color in the Boettcher Tropical Conservatory.</p>
Recently, we planted a new addition in the Boettcher Tropical Conservatory, Brugmansia sanguinea</em>, or the ‘red angel’s trumpet.’ This crimson-flowered tree will surely be a treat when in bloom. Brugmansia</em> is a genus of trees and shrubs consisting of only seven species. These pendulous-flowered beauties are members of the Solanaceae family, commonly known as the nightshade or potato family, and this is seen through the flowers. Yes, it is true, that Brugmansias are related to potatoes and tomatoes, although you would not want to eat brugmansia. Many members of the Solanaceae family are toxic and Brugmansia is no exception. Brugmansia sanguinea</em> hails from the Andes and is native from Colombia to Peru and Bolivia. The genus Brugmansia</em> is broken in two sections: section Brugmansia,</em> the warm growing brugmansia, and section Sphaerocarpium</em>, the cool growing brugmansia. B. sanguinea</em> lives up to its classification as a cool-grower, and can withstand short frosts, although it doesn’t like temperatures under 32 degrees Fahrenheit for prolonged amounts of time. Brugmansia trees and shrubs make great houseplants, and many colorful hybrids exist that are readily available through a variety of nurseries. They may be kept in a pot on your porch during the summer and brought in for the winter. If you don’t have anywhere to store the potted plant during the winter months, you may prune it and store it bare-root in a cool, dry place and repot in the spring. This tropical gem is definitely worth a stroll through the Boettcher Tropical Conservatory, even if not in flower, but keep your fingers crossed as it has been putting out more blooms lately. You will find the plant towards the West end of the conservatory just past the pandanus tree. Hope to see you soon! For more information on growing Brugmansia sanguinea</em>, click here to visit the "Strange Wonderful Things" Web site.</p>
</p> Autumn is imbued with intimations of mortality: dying leaves, dormancy, doom, gloom, Hallowe'en colors and ghosts and spooks: Boo! Gardeners know another side of this "season of mists and mellow fruitfulness": there are a number of plants that only begin </strong>blooming in September, with one or another species coming on until the spring: Hellebores, crocuses, cyclamen and witch hazels are all plants that have a different notion of the growing season. It's their spring right now! A well stocked collection of any of these genera begins with heavy bloom in October and one or another will keep blooming right until the hot days of late spring when they go dormant (so to speak) for the summer doldrums. These are my kind of plants! Crocuses for most of us means the bright orangy-yellow Crocus flavus </em>or C. ancyrensis</em> among a host of others, not to mention the Dutch giants derived from C. vernus</em>. Although pitifully few Coloradoans grow them, crocuses will thrive almost anywhere they are planted in a Colorado garden: dry or wet, sunny or shady. They love it here. Now is a great time to plant these spring bloomers for a splash of color in February and March. There are another group of true crocuses that wait until October to put on their show. These you must order early in the season and plant in September preferably. Denver Botanic Gardens boasts wonderful plantings of these in many gardens: they are among the largest flowered plants in their genus and have flowers of a luminous shades of lavender, purple and occasionally white. Ten days ago we had a precocious bout of winter that froze many leaves and diminished our autumn beauty. But I have never seen the autumn crocuses bloom more spectacularly than they have the last few weeks. I am not talking about the pink Colchicums that go by that name (they are mostly done and are in the Lily family and have six stamens: true crocuses are related to irises and have only three stamens!). Above you have Crocus speciosus</em>, the commonest and bluest of the autumn crocus which is blooming in the east west pathway and the Rock Alpine Garden right now. Below is C. nudiflorus</em> in my own home garden. An even darker C. medius</em> will be blooming the next few weeks in the Rock Alpine Garden. Remind me to order more of these and the rest next year for my garden! To walk into a garden where dozens of unearthly, fluted goblets of autumn crocuses are gently trembling in the autumn breeze is heavenly. It's as though they are toasting the start of the crocus season with their beakers, full of sky blue or evening lavender. Cheers! </p>
Have you ever wondered what really happens within plants to help them carry on through the winter? As autumn approaches, the sun begins to set closer to the horizon, leading to cooler nights and shorter day lengths. This sends a warning signal to plants that winter is soon approaching and that they need to get ready to go into dormancy, which is similar to hibernation in animals. During dormancy, the plants stop growing, fluids within cells stop flowing and the tender growing tips are enclosed in a tight, frost resistant bud. Before entering this dormancy, the leaves of the plants turn from green to yellow, orange, or red before dropping to the ground. So, what causes the change in leaf color? In leaves, both the green chlorophyll and the yellow-orange carotenoid pigments occur within the chloroplasts. Since there are more chlorophyll pigments than the carotenoid pigments, the leaves appear green. In the fall, the chlorophyll pigments decompose allowing the caretenoids to express themselves as orange and yellow. In some plants, the leaf cells produce red pigments, the anthocyanins. In these leaves, once the chlorophyll has decomposed, the anthocyanins mask the caretenoids, thus turning the leaves red. The change in color and dropping of leaves are the plants' way of avoiding freezing damage to themselves. During freezing, the water within the cells of leaves turn to ice, causing disruption of the tissues. These damaged tissues become inviting sites for fungi and bacteria to invade the plant. In order to prevent microbial invasion, plants drop their leaves and form a protective seal over the areas where the leaves were once attached before the freeze damage can occur. Even though plants look lifeless in the winter, be assured that they are ever sensitive of their surroundings, keeping tabs on the temperature and day length before getting ready to spring back to life!</p>
