</p> </p> It's snowdrop time again! Surely, no plant is more intimately associated with winter flowering (okay, okay--Christmas roses may be!), and none have developed such an enthusiastic folowing: there are many specialty nurseries that sell dozens, even hundreds of kinds of snowdrops. Almost exactly a year ago I told the story of a snowdrop that fetched hundreds of dollars at Ebay auction. But truth be said, all snowdrops are precious this time of winter!</p> </p> Galanthus elwesii at Denver Botanic Gardens</p> The plant that now constitute our most robust colony behind the Succulent House along the Cheesman gate were originally used as "fillers" in a lobby court display: I rescued them and planted a couple dozen bulbs some twenty years ago. Each bulb has proliferated and this is now beginning to make quite a spectacle. Starting up just now (go check it out!). Here is a closeup of the commoner species that is abundant in the wild across much of Europe. I have grown this for over a half century at various homes--it spreads abundantly in Colorado as well--but believe me, this isn't a weed. You can always find homes for this plant. I remember this as a child in my parents home--just a few clumps here and there that spread to cover square yards by the time I was in college... Here you can see now Sandy Snyder (who worked at Denver Botanic Gardens for 17 years in the 1980's and 1990's) has managed to naturalize one of the tougher sorts in her sparsely watered buffalo grass in sun! Generally, they are recommended for shady spots where they get periodic irrigation, but many species are Mediterranean littoral plants that grow in areas that have no water from April to November. I suspect we could find sorts that would thrive with no supplemental irrigation. Three of many books recently published about Snowdrops: </p> </p> </p> By the way, if you Google "snowdrop" you will find a host of novels, mysteries and other books named for these winter beauties--they are obviously popular--especially in Europe. By the way, all the snowdrop monographs have glowing reviews--and the prices are beginning to get astronomical--obviously the time to invest in snowdrop futures! Remember to order some for planting next fall (the plants of course--not the books).</p>
Yes, Virginia...pampas grass (Cortaderia selloana</em>) does indeed grow in Denver...although not in great numbers. Observant visitors will have noticed them dotted here and there at the York Street gardens, and I have seen another half dozen driving around Denver. The one above is right next to University Avenue, and constitutes a minor traffic hazard as grass-afficionados notice it and swerve! I suspect the owners purchased it via mail order, since these are rarely sold locally ("pampas grass is not hardy" according to most pretty well-informed nursery folk. And I agree, most are not. Only the dwarf, high elevation forms are apt to be hardy here, and these are hard to find). Most Coloradoans probably don't know that pampas grass is a pestiferous weed in California--but then one man's weed is another man's treasure. I doubt that this will ever pose much of a threat in our climate. I share this picture to show that much of the creative work of plant experimentation is undertaken by home gardeners. We at the Gardens sometimes have to run to keep up! Here you can see from closer up the silky, silvery color that true pampas grass has seemed to perfect. If you have driven parts of Texas you are sure to have admired pampas grass--a popular landscape plant in that state. I used to drive down at Thanksgiving each year, and the clumps of pampas here and there along the way were like mile posts, or sentinels that cheered the trip. Their fluffy seedheads are amazing when they puff up. Alas! A well established clump is so massive that cutting it back each year is a chore. This is one of the hazards of growing large grasses anywhere. Confusingly called "hardy pampas grass" (a paradox if you think about it...), this is the most commonly planted giant grass around Denver. I am sure half the people who grow it think it is pampas grass, and if you look up and compare, you will see there is a family resemblance. But while the TRUE pampas grass comes from South America as the name suggests, Ravenna Grass is from the Mediterranean. This still grows abundantly in the coastal marshes near Ravenna I've been told. This is by far the most vigorous and giant of commonly grown grasses, and a large clump will often produce vigorous seedlings nearby that should be dug while young. A large clump needs a front end loader to move or remove...be warned! Until recently it was classed as an Erianthus</em>, but has been put in the same genus as sugar cane in the last decade or so (Saccharum</em>). Sugar cane has helped make Brazil energy self reliant. Maybe this vigorous grass has biomass potential? The group that has been exploited most for that in America is another genus altogether, however... There are hundreds of cultivars selected from the various species of Miscanthus</em>--which is also often sold as hardy pampas grass. They are hardy enough but the name is taken, I'm sorry. A great deal of research is being done on these because of their famous C4 metabolism which allows them to accrue enormous biomass in short periods of time. Miscanthus have nevertheless been practically banned in much of the eastern U.S. due to their propensity to produce colossal seed crops. I have yet to see a seedling appear in Denver outside, so I think we can grow these without guilt--except that these are the most water demanding of these larger grasses. Don't try them in your Xeriscape! My current favorite giant grass is native not far from us here in the Rio Grande Valley. Plant Select has chosen to feature this plant in 2006 and I can vouch for its toughness. The plant you see in the picture is in my garden, on very sandy soil where it bakes for months on end and gets precious little water. Even so, it makes a fabulous fountain of golden seedheads that persist through the winter months. Indeed, all of these pictures were taken this morning, January 24. The greatest reason to grow these pampas grasses (and their pretenders too!) is that they provide drama, beauty, movement and interest in the depths of winter for months on end. If you grow them, please resist cutting them back until February so we can enjoy their splendid display! But do cut them back hard so that the new growth will be fresh and green for the coming year!</p>
Xeriscape sometimes summons images of oceans of gravel and harsh, stickly, pointy plants that stab, slash and terrorize homeowner associations. A primrose? Really? Well, there are even primroses that can do with much less water than many people pour on their gardens, and the oxlip (famous in English Literature--even Shakespeare writes about it!) has proved itself for decades in a number of local gardens. Thanks to the Plant Select program, this and a host of other unique plants will debut across the country this spring. Oxlips do best in at least a half day's shade, but given a rich soil, mulching and occasional good watering, they will even grow in full sun in Colorado. They combine especially well with graceful, brilliant blue flowers like the Siberian squill pictured above. Although quite widely distributed in the foothills of the Southern Rockies, I have only stumbled on Scott's clematis a few times, so I suspect it is not exactly abundant. It has been produced abundantly by Plant Select propagators this past year and you should be able to find it in local garden centers this spring. The nodding, lavender bells vary from almost gray to a dark, almost black blue in some forms. As you can see, it makes a compact mound with those irresistible blue bubbles visitors at Denver Botanic Gardens simply have to squeeze...speaking for the plant, please don't! This clematis belongs to the "Sugarbowl" section of the genus (sometimes classed as its own genus: Viorna</em>) which includes a dozen or more of the rarest and most beautiful herbaceous clematis. This is likely to be the most drought tolerant of the lot--and the flowers last for much of the spring and early summer: we have had flowers into the autumn on larger plants--and the seedheads are a bright gold and almost as decorative. This plant is a must have for anyone interested in growing xeric plants. The "alumroots" (a dreadful name), or coralbells (whew!)</em> are entirely restricted to North America, mostly concentrated in the Western States and Appalachians. They have been intensively bred for foliage color by Terra Nova nursery in recent decades. I love the wonderful lacy flowers that brighten up dark cliffs all over the west. This is one of the most restricted in nature, but most accommodating in the garden. These three plants are the first sampling of Plant Select Petites, an expansion of Plant Select which seeks to provide more compact plants for the more intimate setting many of our more modern urban and suburban patio gardens, permanent outdoor containers and ever popular rock gardens which have become a hallmark of regional horticulture. There are another five outstanding introductions that continue to expand our regional palette of adapted and gorgeous plants that provide year around interest with less fuss, water and grief. I will write more on these later this spring... But I believe a trumpet blast is merited at the start of the new year for a new facet of this extraordinary program that has put tens of millions of wonderful plants into gardens across America and beyond. One of my favorite maps shows precipitation in North America where 20" or less is shown in red shades and 20" or more annual precipitation is progressively bluer. The east half and far left coast of America are bluish to be sure, but much of the middle and all the West except the mountain tips is painted in bright pink shades--nay! much of it quite red or deep vermilion. Drought is the norm</em></strong>. Each snowfall lulls us into complacency--but do remember, we live in a semi-arid region in which prolonged, deep drought is not an unusual event. Stop watering for a week or two in summer and you'll figure it out if you haven't yet. If our gardens are to survive into the future, it behooves us to develop a palette of plants that will be viable in our progressively more water restricted landscapes of the future. Thank you, Plant Select for leading the way! And keep up the good work.</p>
With this remarkable string of warm days in November, we can hardly be blamed for thinking summertime, and summertime is fast approaching in the foothills of South Africa, where the spectacular genus Kniphofia </em>finds its greatest concentration of species. It is likely that the vast throng of ornamental monocots that emanate from South Africa--exemplified by the Torch Lilies--will be the largest group of plants of that great flora to impact North Hemisphere gardens. It is mysterious to me why there are so many thousands of extremely showy monocots--especially in the Iris, Amaryllis and Lily family (the latter in its very widest sense) concentrated in such a small geographic area. South Africa possesses the highest biodiversity in petaloid monocots on Planet Earth--much as it has the largest number of species of succulent plants concentrated in one region. This late summer blooming torch lily made an eye-searing focal point in the lower meadow of the Rock Alpine Garden last August: Kniphofia caulescens</em> is among the hardiest species in this diverse genus, and this species has been championed by Plant Select. The variability in the genus Kniphofia </em>is truly astonishing. This massive species (Kniphofia Northiae</em>) has been growing in the Rock Alpine Garden for nearly 20 years. It is one of the largest in the genus, and one of the first to bloom as well. I shall never forget finding a vast slope of these on Bastard Voetpad Pass in the East Cape in January of 1994, stark black stems from having gone to seed--I'll bet they're blooming there right now as I type this in! (Bastard Footpath is the translation of the Pass's name from Afrikaans--for this is the pass those rascally sheep rustlers would take to poach lambs and take them back to the KwaZulu Natal lowlands--a little sociological aside there.) What could be more iconic of South African monocots than the grossly misnamed "Lily of the Nile"? Of course, the great concentration of Agapanthus</em> species are concentrated in the southeastern Cape regions and Drakensberg where Agapanthus campanulatus</em> var. patens </em>climbs to alpine heights (Not exactly the Nile, don't you know?). In January of 1994 (midsummer in South Africa) I was astonished to find the cliffs above Harrismith on the Platberg positively swathed with blue agapanthus--a banner year (when I went back a few years later, there was not a single one blooming at the same time of year). These perform far more predictably in cultivation where they can get more regular watering. They color up the South African Plaza every summer--as well as the Lilac Garden perennial beds and other spots around Denver Botanic Gardens. They make stunning companion plants to Kniphofia </em>cultivars that bloom at the same time, like K</em>. 'Alcazar' or K</em>. 'Royal Scepter'. One rarely sees Galtonia </em>planted in Colorado gardens, even though they are sold very cheaply as "summer bulbs" by mail order nurseries. Not nearly enough local gardeners take advantage of these spring planted bulbs--especially since many (Galtonia, Eucomis, Crocosmia</em>) are extremely showy and reliably perennial garden plants in Colorado under typical irrigated garden conditions, that is. Almost the only Crocosmia </em>one sees in the Front Range area is Crocosmia </em>'Lucifer'--a stunning hybrid bred almost a half century ago by Alan Bloom of Bressingham Gardens in Great Britain. I was astonished to find a hybrid very similar to this growing rampantly in the foothills of the Drakensberg on my recent trips--native plants can become invasive in the wrong places, obviously. But in Colorado, this is a very restrained and amazingly hardy and showy plant. I have seen it growing lustily in gardens in Vail. Since many local garden centers sell this in pots like a perennial, it has made small inroads in more sophisticated regional gardens. My mentor, Paul Maslin, grew a wide variety of Crocosmias throughout much of the 20th Century in his home in Boulder--most of which I have not seen elsewhere in Colorado. This is possibly one of the most neglected genera of plants for our regional gardens. I first saw this blooming alongside North's Kniphofia (the latter was in seed) on that same Bastard Voetpad Pass...this is a local endemic of the East Cape, and has been thriving at the Garden at Kendrick Lake for a decade or more. Many local horticulturists are often surprised to find typical hybrid Gladioli forming big clumps and proving to be winter hardy: these are usually hybrids of Gladiolus dalenii</em>, another species that often grows at high elevations. There are many more high altitude species that should perenialize in regional gardens once we obtain them. Moraea </em>is one of the largest genera of South African monocots, and one of the most beautiful. This species has thrived for us at the Gardens for nearly three decades. It grows along streams and in moist swales everywhere across Lesotho and the Drakensberg escarpment. Since it is poisonous to livestock, has persisted and perhaps even spread despite the horrendous overgrazing that takes place over much of its range. It has an uncanny resemblance to a yellow Siberian iris, and grows and thrives alongside these in roughly the same garden conditions. Unlike true irises, many Moraea </em>have evanescent flowers that usually last only a single day in hot weather. But this species keeps producing flowers for weeks on end. It has a distressing habit of trying to be evergreen. If you do grow it, make sure you keep the foliage growing all winter long. By spring it can look a bit bedraggled--only then cut it back (like lavender it can die back if cut back hard in late autumn). Like much of Colorado, the natural ecosystems throughout most of South Africa are comprised of grassland, and there are no end of extremely beautiful and unusual grasses that come from that region, many of which are proving to be fine garden plants in Colorado. The first to find its way to local gardens has been this wonderful bunch grass, Harpochloa falx</em> is mostly found in mid-altitude grasslands in the Drakensberg. It needs regular irrigation and perennial border conditions in Colorado to grow well. Although it bears a striking resemblance to Blue Gramma grass (Bouteloua gracilis</em>), and especially to the robust cultivar introduced by Plant Select (Blond Ambition) which I featured in a recent blog post, the resemblance is entirely accidental--they are on very different branches of the Grass Family tree (a mixed metaphor if there ever was one!). As I scroll back over the monocots I have featured in this blog, I am impressed with how incredibly vivid and colorful so many of the wildflowers are in South Africa. Why do these resonate so brightly in North Temperate Gardens?Anthropologists postulate that the very first humans evolved on the Highveld of that country and nearby Savannahs a bit further north. One cannot help but wonder if they have not branded their beauty in our souls somehow, deep in our human genes, over the course of our mutual coevolution as Australopithecines and finally Homo</em>, on the windy, aromatic Highveld, the prairie, the steppe of South Africa? We humans are but interlopers in the Northern Hemisphere--immigrants who have come in the blink of a Geologic eye, and perhaps we are finally and simply bringing our ancestral flora along to remind us of home?</p>
No, Virginia! Those are not flowers,but the seedheads on one of the most remarkable and beautiful shrubs (or is it a tree?) from China. Heptacodium miconioides</em> was discovered by E.H. Wilson in Hubei province in China in 1907, but only introduced to cultivation in 1980 when seed was grown at the Arnold Arboretum, which distributed plants a few years later to members. One of those original plants is featured at the end of this blog. Not only are the seedheads in late autumn spectacular, but the flowers are a lovely, pure white: it blooms much of August and September. If you come close you will smell an indescribable, sweet fragrance that is somehow tropical, rather like the exotic shape of the leaves with their long drip tips. The smell is strongest in the evening and at night--almost overpowering at times (but no one complains!). Here is a particularly floriferous plant I photographed ten years ago in Massachusetts. Here is the oldest specimen at Denver Botanic Gardens, planted in the late 1990's, already almost 20' tall. This is coming into full bloom right now, and should be spectacular much of the next month: do come sniff it! Here is the largest specimen in Colorado (that I know of): Solange Gignac, who worked 23 years at Denver Botanic Gardens, obtained one in 1983 the first year they were distributed--so this is now in its 30th year of growing. It is 30' tall and growing--a magnificent plant I would characterize as a tree. Not only are the flowers and seedheads beautiful, but the bark is appealing all times of year. A mature specimen develops a trunk rather like a Crepe Myrtle--mottled and glistening with time. This seems to have great cold hardiness and thrives in a variety of sites and soils. It needs average irrigation in Colorado (it is not a desert plant), but has such sterling qualities that Plant Select has promoted this as a recommended plant for Colorado Gardens. Solange Gignac passed away a week ago today: I know that every time I admire our wonderful specimens growing in several gardens around DBG (Rock Alpine Garden, Plantasia, Plant Select), I shall think of her, and her love of this plant. It's sweet fragrance will remind me of the years of sweet companionship and friendship, and her great contributions to our community and Helen Fowler Library.</p>
Anyone who has managed to grow "Red birds in a tree" knows that few plants are more attractive to hummingbirds. Scrophularia macrantha</em> is a very local plant endemic largely to a few mountains in central New Mexico. The genus usually goes by the common name "Figwort" and gave its name to the Figwort Family--(Scrophulariaceae), which opens up another can of worms--let's leave that for another blog! But this plant is notable for several reasons: it is unquestionably the queen bee of its genus (Scrophularia </em>is widespread in the old world, where most species are black or brown flowered--charming, I'm sure!). It makes a striking specimen in a border or wild garden--but stand back! It can grow six or more feet tall in gardens. T This monumental specimen is growing on Alameda, in Lakewood's amazing median strips that are filled with choice xeric plants. I nearly had an accident the first time I saw this growing here--such a rare plant, in the middle of a busy street! Lakewood can be proud indeed... Here is a compact form that popped up a few years ago in the Lakewood Showcase garden on Hoyt and Jewel (the "Gardens at Kendrick Lake": if you have not been there, hightail it out there pronto: it is a stunning xeriscape demonstration garden that looks good at all times). I collected a pinch of seed of this twenty years ago exactly this August at about 6000' in Luna County, New Mexico on an expedition with my brother-in-law, Allan Taylor to get seed off the northernmost Arizona Cypress in New Mexico. There was only one plant of the Scrophularia</em>, and it was in seed: I sent a smidge to Kew and shared the rest with a few friends. David Salman of High Country Gardens was the first to successfully grow and market the plant, and he gave it its wonderful common name. In 1998 it received the Green Thumb Award of the mail order nursery association. Ten years later it was promoted by Plant Select, and today nurseries across the world sell this plant, so rare in nature but treasured in gardens. We have been finding hummingbirds in Denver area gardens all summer in recent years (they used to only pass through on the way to the mountains in spring and fall). More intriguingly, their numbers swell enormously in dry years like this year: I sometimes wonder if the vast array of red flowered, hummingbird-pollinated plants in Plant Select (a bevy of Salvia</em>, penstemons galore, Agastache </em>spp. and this Scrophularia</em>) are not providing such a smorgasbord of delights for them that they find lingering down here attractive. I know that when flowers are sparse or absent in the hills, our gardens may be providing a vital food source for these miniature avian gems--a fascinating unintended consequence of our plant exploration. Pretty cool, no?</p>
With the beautiful, warm weather recently I have spent a lot more time outside and have enjoyed watching the first signs of spring every where I look. My chives are coming up in the garden and my lilacs are leafing out. Here at the Gardens there are so many plants starting to bloom, from the daffodils to the magnolias. Observations like these make up the science of phenology. Phenology is the study of relationships between climate and the seasonal events, like flowering dates. Phenology is one of the most sensitive and easily observed indicators of biotic response to climate change and is affected by factors such as temperature, water and nutrient availability, and timing and duration of pest infestations and disease outbreaks. We use phenology to manage timing of seasonal work, like crop harvest and pest management. Organizations like the USA National Phenology Network gather phenological data from all types of contributors (including researchers, educators and citizen scientists) to understand the impacts of climate change on phenology. Efforts such as these provide valuable data to scientists that they otherwise would not be able to gather on their own. This year, the Gardens is getting involved in plant phenology by participating in the Project BudBurst Cherry Blossom Blitz March 20-April 30, 2012. Project BudBurst is a network of people across the United States who monitor plants as the seasons change, collecting important ecological data on the timing of leafing, flowering, and fruiting of plants (plant phenophases). The data are being collected to allow scientists to learn more about the responsiveness of individual plant species to changes in climate locally, regionally, and nationally. We encourage you to explore the cherries here at the Gardens. For each plant, you can participate by observing the phenophase of one or more cherries and share your observations on the Project BudBurst website or the Android Mobile BudBurst app. Whether you are observing cherries here at the Gardens or in your own yard, I encourage you to think about the significance of that observation and how valuable your data can be when combined with those of other citizen scientists across the country…every observation counts.</p>
</p> There are a number of plants that are clever enough to bloom during the winter months: none more predictably, nor beautifully, however, than the ill-named Christmas rose (Helleborus niger</em>). There are a few selections of this species that often begin to bloom in October or November most years, and yes, these may happen to be in bloom for Christmas. But invariably by January, I always have a few of these huge, waxy white flowers opening in my home garden. Mike Kintgen reports that they are blooming in the Rock Alpine Garden right now, and likely in one of the many other gardens where these are planted at Denver Botanic Gardens.</p> </dt> Helleborus niger at Denver Botanic Gardens Waring House, March 2011</dd> </dl> So why not call these "New Year Roses"? a more apt and accurate name...oh well. Fat chance. Christmas has a stranglehold on the name. There is a whole industry in Europe cranking out Christmas cards with paintings of these lovely plants. I'm sure there have been tens of thousands of these over the years. I love the thick, leathery leaves, with their lyrate pattern almost as much as their blooms. The foliage makes a wonderful evergreen fountain of color year around, and make a graceful setting for these enormous flowers. I have seen these nearly 3" across in some forms: the petals are thick and waxy and simply gorgeous. Some age a deep rose red. It will bloom through thick or thin (and we are sure to have some very cold weather still) for the next three months: a marathoner if there ever was one! There is an enormous amount written about this plant in books, magazines and the web: worth browsing. It has accumulated great herbal lore (don't try it, though: it's very poisonous!), and a great deal of myth. I finish by saying that it loves Colorado, and should be planted by everyone here. Give it a good loam, enriched with a bit of humus in part shade. Don't let it dry out too much (especially the first year as it establishes). Once established in the right spot, this is quite tough, even somewhat xeric and likely to last in the garden for the rest of your life! (You can't say this about many herbaceous plants)...There are a wealth of hybrids of Christmas rose becoming available, not to mention a veritable revolution occuring with Lenten Roses: these, however, are mere distractions and side shows as far as I'm concerned: this is the Queen flower of winter. Let us bow down in wonder and worship! (I do anyway).</p>
From time to time, the greenhouse team at Denver Botanic Gardens will build hypertufa troughs. These troughs are a great addition to a garden, especially for showcasing some of the rock garden plants, native wildflowers, and cacti that might otherwise be lost in a larger landscape. We sell our planted troughs at the Spring and Fall Plant Sales and occasionally throughout the season at the Shop at the Gardens. However, if you are interested in making your own hypertufa troughs, I would like to share with you our process and recipe for making a simple hypertufa trough.</p> </p> Supplies</strong></p> For this project, you will need the following supplies:</p> Portland cement (either white or gray--if you are using a dye, the color of the cement will effect the dye)</li> Vermiculite</li> Sphagnum peat moss</li> Concrete dye</li> Synthetic concrete reinforcement fibers</li> A plastic mold, such as a large bowl, a cat litter tray or a dish pan</li> 1mm or thicker plastic sheeting (this can be a thick trash bag, a painting drop cloth, etc.)</li> Water</li> </ul> </p> Where to get supplies</strong></p> In the Denver area, most of these supplies are readily available. The peat moss and vermiculite can be found at most garden supply centers or at a large retail horticulture products supplier. The Portland cement, concrete dye and synthetic reinforcement fibers can be found at any specialty concrete supply store.</p> Supplies prep</strong></p> The task that will take you the longest in your trough making endeavor is the materials prep. The cement and vermiculite can be used as is. It is advised that the peat moss be sieved to remove large particulates and to provide a smaller grain material. However, if your goal is a coarser appearance, the sieving is not necessary.</p> The materials that take the most prep time are the synthetic fibers. When they are purchased, the fibers have the appearance of clumps of white strings. The fibers are added for stability and need to be consistent throughout the batch. To obtain this consistency, the fibers need to be ‘fluffed’ before they can be added to the mixture. This can be done by rubbing the fibers between your fingers until they take on the appearance of a pile of cat hair. It can be quite time consuming, but definitely worth the effort.</p> </p> Tools</strong></p> Dust mask</li> Rubber gloves</li> Wire brush</li> Propane torch</li> A bucket or container for measuring your dry ingredients</li> Wheelbarrow or suitable container for mixing the hypertufa</li> </ul> Mixing the hypertufa</strong></p> Once you have obtained and prepped your materials, it is time to mix the dry ingredients. It is advisable to always wear a dust mask and rubber gloves when working with Portland cement. We have experimented with several recipes; the following recipe is our favorite for strength and appearance:</p> 2 parts Portland cement</li> 3 parts vermiculite</li> 3 parts peat moss</li> 1-2 cups of dye (depending on the color you are hoping to achieve)</li> 3-4 cups of ‘fluffed’ synthetic fibers (this will translate to about a 1/4 cup unfluffed fibers). These fibers will not be added to the dry mixture; rather, they will be mixed in as you are adding water.</li> </ul> The size of the trough (or troughs) you are hoping to obtain will determine the amount of hypertufa you mix. If your goal is to make one small trough, the bucket you are using to measure out your ‘parts’ should reflect this size.</p> </p> Once you have mixed up your dry ingredients in the wheelbarrow/mixing container, it is time to add water. It is important to only add a little bit of water at a time; if your mixture becomes too wet, the end result will not resemble hypertufa. If you have a partner to aid in this process, the extra set of hands will be very helpful. While one person is using a shovel to turn the mixture, the other person can be incrementally adding water and synthetic fibers. This is also a good time to make any adjustments to the color of the mixture by adding more dye, if necessary. The desired result is a mixture that when squeezed in your hand both holds its shape and releases just a few drops of water. If you squeeze the mixture and it feels squishy or you can visibly see a lot of water forcing out, you have added too much water.</p> </p> Filling the forms</strong></p> Now that your mixture is ready to go, it is time to start making the trough by adding the mixture to the form (the plastic container) that you have chosen. As you will have to cover the finished project later with the plastic sheeting, it is a good idea to lay the sheeting down before you begin the molding process. As this is also a bit of a messy project, the sheeting will protect whatever surface you are working on.</p> In general, regardless of the size of your trough, you want the walls and bottom to be between 1-1/2 - 2 inches thick. Begin by adding shovelfuls of mixture to your form. This mixture needs to be compacted (to form the base) either by pushing with your hands or using a block of wood to push it down. If you do not compact the hypertufa, as it dries it will form holes in the trough and will generally lose stability.</p> As you are forming the base, start working your way of the side walls of the form. If the walls of your form are somewhat steep, it may be difficult to compact the mixture against the form. If this is the case, you can try compacting the mixture in your hands and then apply it to the inside of the form.</p> As you continue to build the walls of the trough, remember to keep the thickness consistent. It is very important that you make a drain hole in the bottom of your trough. If the trough is larger, you may want to make two or three holes. This is the best time to make the hole; if you forget, it will be necessary to drill it out once the trough has dried.</p> Curing</strong></p> Once you have molded the hypertufa in to the form and you are happy with the way it looks, it is time to begin the curing process. This is a two stage process; the first part lasts between 24-48 hours and the longer curing should take about four weeks.</p> Immediately after finishing the molding process, you will cover the trough with the plastic sheeting. Between 24 and 48 hours you will remove the trough from the form and leave it under the plastic sheeting. When to remove the trough is determined by the hardness of the mixture. If you can scratch it with your fingernail, it probably needs about 12-20 more hours. If you need a screwdriver to scratch the surface, this is about the right hardness. In general, smaller troughs take longer to cure than larger ones.</p> To get the desired appearance for your trough, this is the time when you would use the wire brush to rough up the outer surfaces of your trough. Most likely the plastic form will have left the trough looking shiny and smooth. Typically, hypertufa troughs have a rough and more weathered appearance. The wire brush will help you alter the texture to your liking. To make the trough as strong as possible, the longer curing method is recommended.</p> Once you have removed the trough from its form and altered the texture, place the trough back under the plastic and keep it at room temperature for four weeks. You will want to occasionally check the trough to make sure it is not drying out. If it feels dry, moisten it with water. After the curing process, if all goes well, you are ready to plant your trough! Remember to use well-draining soils and chose plants that are suitable for troughs.</p> </p>
</p> Colorado is reputed to have such a harsh climate that many trees could never grow here, like flowering dogwoods (Cornus florida) or Sweetgums (Liquidambar stracuiflua</em>). Once again, conventional wisdom is proved WRONG </em></strong> by Denver Botanic Gardens! We boast a fabulous specimen not far west of York St. in the Sensory Garden: I have admired this the last ten or fifteen years it has been growing rapidly, but only last year and this year has it finally fulfilled my expectations for fall color: right next to our only Sassafras</em>, it rivals that magnificent tree in its fiery foliage. Yes, yes...I know we had 8" of wet snow yesterday. Both Sassafras</em> and Liquidambar</em> (and most every other tree at the Gardens) came through very well. Everyone panics with our untimely snows (and we do get them every year!), but plants are resilient, and the better plants are almost immune! So keep planting better plants!</p> </p> "Boston ivy" (Parthenocissus cuspidata</em>) is not seen nearly as much as English ivy in Colorado. This Japanese cousin to Virginia Creeper is rather neater in growth form--rather resembling a deciduous English Ivy--and the fall color is often quite good. This year it has been exceptional. The Waring house positively glows!</p> </dt> Closeup of Parthenocissus cuspidata ("Boston" ivy)</dd> </dl> Every keen lover of fall color I speak to says the same thing: this has been a magnificent year for fall color. When Green Ash (Fraxinus pennsylvanica</em>), American elm (Ulmus americana</em>) and all the Lindens turn brilliant yellow and positively glow you know it is a really good fall color year. Combined with the ubiquitous scarlets of Freeman Maples (Acer freemanii</em>) and the glowing deep purple and gold of White Ash--which is also very popular--the street scene around Denver was very New England. I have a hunch that the show will continue well into November. Colorado does Indian summer with a vengeance, don't forget! With our Allan Houser sculpture exhibit, it is all the more appropriate it do so.</p>
