The Alpine Rock Garden at the Denver Botanic Gardens is world-renowned for its diversity and collections of high-elevation alpine plants, and western US native plants, steppe plants and succulents. One of the largest rock gardens in the United States, I saved this garden for a different day, as it deserved a more focused visit. Rock gardens can be controversial - at least properly defining them when garden geeks get together. Even today, many gardeners cannot agree on where they should be gardens filled with rocks, or gardens constructed to house true rock plants or alpine plants. The Alpine Rock Garden at the DBG is a little of both - but it is clearly inspired by the great European rock or alpine gardens from the turn of the century. This garden houses many plants native to the prairie and steppe areas of the great American south west. Purists may grumble, expecting to see sweeps of gentians and pulsatilla such as those seen at Kew or the Montreal Botanic Gardens, but the DBG garden is unique in the world of alpine gardens, and it is often listed as one of the great three ( Kew, Edinburgh and Denver) Rock Gardens maintained today. It alone is worth a visit while in the Denver area.
|MANY TRUE ALPINE PLANTS GROW DENSE AND TIGHT UNDER THE EXTREME CONDITIONS FOUND AT HIGH ELEVATIONS. THE TIGHT GROWTH HELPS THE PLANTS CONSERVE ENERGY, AND MANY FORM TIGHT BUNS AND TUSSOCKS, LOOKING MUCH LIKE THE ROCKS WHICH THEY GROW NEXT TO,|
|A NICE, WHITE ALPINE CAMPANULA|
|A NEW FEATURE AT THE DENVER BOTANIC GARDENS IS THIS CZECH STYLE CREVICE GARDEN, NEWLY PLANTED WITH ROCK PLANTS.|
|Ehedra przewalskii, WITH RED BERRIES. IT'S IN THE JOINT FIR FAMILY- EPHEDRACEAE
A POISONOUS PLANT, THIS IS THE EPHEDRA THAT CAN CAUSE HEART PALPITATIONS
|Phlomis alpina, ALPINE JERUSALEM SAGE LOOKS NICE, EVEN AS DRIED SEED PODS FORM|
|Manfreda virginica, THE FALSE ALOE, NATIVE TO THE SOUTH EASTERN US. STILL A MEMBER OF THE AGAVAEAE ( AGAVE or CENTURY PLANT FAMILY), THE FLOWER STALK WAS NEARLY 5 FEET TALL.|
|A PRAYING MANTIC, HUNTS FOR SNACKS ON A Pelargonium englicherianum WHICH HAS GONE TO SEED|
|A MORE WELL BEHAVED FIREWEED, THE ALPINE WILLOWHERB OR Epilobium fleischeri, ALSO A PLANT SELECT® OFFERING IN THE SOUTH WEST.|
|THIS TINY FLOWER ONLY A HALF INCH IN DIAMETER ON A THREE FOOT SHRUB IS A CLEMATIS.
MEET Clematis stans NATIVE TO JAPAN
|ANOTHER VIEW OF THE CREVICE GARDEN. I WILL HAVE TO COME BACK AND SEE THIS IN JUNE.|
|SENIOR HORTICULTURIST, MIKE KINTGEN, CAN BE FOUND TENDING THE COLLECTION IN THE DBG ROCK GARDEN MOST EVERY DAY, AT LEAST WHEN HE ISN'T IN HIS OFFICE. WHO COULD BLAME HIM!|
|MAIN VIEW OF THE DENVER BOTANIC GARDENS' MAGNIFICENT ALPINE AND ROCK GARDEN|
|PRIMULA ALLIONII X 'JOAN HUGHES'. IT LOOKS BIG, BUT USE THE SPRUCE NEEDLES FOR SCALE|
As many of you know, I adore alpine plants, and some of my favorites are the Primroses ( Primula) which grow near the highest peaks of the world. Here are a few of the highest elevation primula, which happen to be our first blooming primula of the season - much more to come. These are being grown in stone troughs, and in crevice gardens, where the tight spaces allow the primula's roots to grow deep in search of water. Primula allionii blooms very early in the Alps in France and north western Italy, where it grows on steep cliffs where it is protected. Hard to reach, these tiny primroses can grow in the tightest of crevices. There are many named forms and selections of P. allionii, and in England, a plant grown in a cold alpine house with care, can be covered completely with flowers so thickly, that you cannot see the foliage ( see one here). In North America, we are lucky if we get 5 or 6 flowers, which are still beautiful, especially this early in the year.
|PRIMULA MARGINATA, A HIGH ELEVATION PRIMROSE, WITH SERRATED LEAVES AND VIOLET FLOWERS.|
|PRIMULA MARGINATA, GROWING IN A CZECH STYLE CREVICE GARDEN, WHICH MEANS ROCKS VERTICALLY PLACED CLOSE TO EACH OTHER LIKE A SANDWICH.|
There are many named selections of Silver Sax's as well as many species but they are not easy to find. One must either mail order them from a handful of alpine plant nurseries ( mine are from Wrightman Alpines) or, one can start them from cuttings that you can take from a friends' plant. I plant my cutting in holes that are drilled into Tufa rock, a limestone rock which is porous, and also hard to find, but worth searching for at alpine nurseries, for it is the only rock that these planted will grow in. You might try these alpined in soil or a gravelly mix, but between you and me, there is really only one way to grow the giant specimens like these, and that is to root your own plants directly into Tufa rock. Once established, they are rather care free.
A silver saxifraga growing in a trough. I still need to clean up the troughs, use tweezers to remove pine and spruce needles, and then spread a new layer of granite chips, but beyond that, there is little care.
This slow to establish beautiful and rarely seen member of the Buttercup Family is perhaps only occasionally seen in plant collector's gardens, but that's a shame, since once established ( it is only difficult to transplant), it can live a long time. As one collector stated, "Adonis are easy to grow, but difficult to find", this is because they plants resist domestication. If one is able to obtain a plant that was carefully divided while dormant, and gets it planted immediately, then one must leave it alone and let it grow undisturbed. If new plants are desired, even seedling resist any disturbance, so although not difficult to raise from ones own fresh seed, success if better if the plant is allowed to drop its own seed into the soil, and young plants moved extremely carefully in the following years.
This is our second year with this division so it is still just settling in, but once established, I expect a dozen or so of these bright cheery yellow buttercuppy flowers very early in the spring, perhaps even with some snow on the ground. It is perhaps the most desired plant by many plant enthusiasts the Ranunculaceae family and its leaves and flowers look very much like the genus Anemone, and not buttercups, which is a good thing. In the garden, the overall appearance in not very buttercup-like at all, and more like Eranthis, the winter Aconite, if anything.
Adonis vernalis is native to Europe, whereas the more commonly seen, if one can say that about Adonis, is the Asian species, Adonis amurensis, which is highly collectible in Japan where many forms have been introduced. Our Adonis vernalis was started from seed collected in the Czech Republic started by Harvey Wrightman's Nursery, where he shared a few plants with us. Harvey WrightmanMostly this is a plant shared by collectors, but look for it, for one could call this the Peony of Ranunculus'. The other species which is sometimes more available is the Asian form, Adonis amurensis. Try ordering it from Asiatica.com.
When I planted the dormant potted division last autumn, I didn't realize that I planted in near a dormant Corydalis bulb clump, so this late summer, I will relocate the Corydalis solida, not the Adonis.
Many non gardeners may think that the winter garden offers little in the way of interest or display. But many plants offer year-round interest, and walking to the greenhouse today, I noticed how pretty my many troughs of Saxifrages look in the winter, with their lime encrusted foliage, and their silvery leaves that are as hard as rock. I am amazed at how sturdy these high mountain plants are, and each and every year, as I add and collect more, their diversity and beauty stops me, and I am reminded of why I love unusual plants so much. You are unlikely to find Saxifrages at your local garden center, or at a big hardware store garden shop. But you can find them online at a few alpine plant nurseries. Saxifrages are worth searching out, for these are one of those things like the finest cookware is to a cook, or a fine imported tool, that get's better with age. Saxifrages seem to say " Hey, you are a serious gardener, and you undoubtedly know what you are doing". Well, if you are like me, you may like things that 'say' that.
Not all Saxifrages are alpine plants, for some are downright huge, and tropical. But it is the alpine species that are so collectable and cherished by rock gardeners, and alpine plant enthusiasts. Saxifrages that are alpines are tiny, lime encrusted plants, and often for dense, hard mounds that alpine gardeners lovingly call buns. The dense buns are hard, and tight, they way we like buns. In the wild, they cling to rocks and cliffs on the highest peaks above the clouds, in in the mist, but they are sturdy and strong, in fact, they are designed for snow and harsh, misty conditions, but, conditions that are exact. T
So why don't you see them everywhere? Well, the reason you don't see them that first, they are considered challenging to grow, and, they are not suited to mass productions for retail garden centers. Plus, they bloom in the late winter, or very early spring. When you see a trendy trough garden workshop on TV or on a make over show, what the host reccomends planting is often hens and chicks, sempervivums, and sedum's. These are incredibly foolproof we all know, but hardly something you can show off or impress with. I like semps, but sempervivums are best left to the casual gardener, for although pretty, they are rather unexciting, and boring, a toddler can grow them.
Saxifrages require an informed mind, and an experienced alpinist to master. ( They don't, but everyone still thinks so, even experienced rock gardeners ( read on) Or, so, they did, for today, I feel most anyone can 'master' growing this once difficult and fussy alpines, but don't share my secret with too many people! Just quietly order some, and pot up a trough, and leave it alone. Then, sit back and watch the most experiences horticultural snob's eye's pop out when they see your trough of these precious, high alpines, all dense and bun like, and you can exclaim...."oh those?, They're so easy, I really don't pay much attention to them". And, here's how...
Here is my big secret - although they are notoriously fussy ( I don't think so, though), they are easy if purchased from one retailer online Harvey Wrightman, for he not only has a premiere collection from the finest sources in Eastern Europe where the best come from ( the Czech's are crazy about Sax's), Check out their Rock Garden site if you want to see some incredible Sax's. But the reason you must get your plants from Harvey is because he grows his Saxifrages in blocks of Tufa rock, which makes them incredibly fool proof.
Look, you can still kill them, but think about this: I lost hundreds of Saxifrages until I bought Harvey's stone grown plants. I have lost none in over 4 years, and although costly, they have grown into large, if not huge, specimens in my troughs. And.....I rarely do anything to them. They get snowed on, rained on, full sun, and rarely watered, they are exposed to all of our New England elements. So, if you've ever wanted a winter garden, or a container that looked as good on the New Year, as it does in March, and in August, then consider planting a trough of Saxifrages, and maybe next year, you too can have a container of stars on your terrace or deck.
The only thing they dislike is winter moisture, and summer humidity. Many of these Saxifrages offer pretty flowers early in the year, perhaps late February or March here in New England, and often are the first sign of spring in our garden, long before the crocus and spring bulbs even think of emerging. Easy to grow in Hyper-tufa troughs, the sort Martha Stewart has shown being made out of concrete and peat, or grown in a frost proof stoneware container, Saxifrages are fun to collect, for there are countless hybrids and species.
The next three posts will show what we did last weekend. IT started with a Trough building workshop hosted by the Berkshire Chapter of the NARGS ( North American Rock Garden Society and Wrightman Alpines) and was held at the home of Berkshire NARGS chapter member Robin Magowan in Litchfield, CT. We then moved on to tour the gardens of another NARGS member, Elisabeth Zander in nearby Goshen, CT. So these three events and gardens deserve three distinct postings, the workshop by Harvey and Irene Wrightman, Robin's garden, and Elisabeth's amazing garden. First, the workshop.
Last Saturday was about a perfect, an autumn day can be in New England, and Litchfield County, Connecticut wasn’t too shabby, either. Joe and I we're fortunate enough to be invited to participate in a trough building workshop arranged by various members of the National Rock Garden Society's Berkshire chapter, and alpine plant nurseryman, Harvey Wrightman, of Wrightman Alpines in Ontario (they ship to the US, thankfully!).
The workshop featured a demonstration on a new way to grow alpines in troughs, which was introduced to Harvey by plantsman and explorer Josef Halda, who is friends with Harvey, and who toured the US and Canada earlier this year while on the NARGS national speakers tour. Halda also stayed with us while in New England in May, but we only discussed this new method, which seemed rather unbelievable, but the results we are seeing are quite impressive.
Saturday's workshop/Demo showed how clay can be used as a growing material for some high elevation alpines when sandwiched between sheets of split tufa (limestone) rock, which is porous.
About 15 of us watched Harvey's wife Irene demonstrate how to wash the soil off of young, potted alpines, or from rooted cuttings, and then focus on how she smeared with a trowel, a slab of rock with the muddy mixture, not unlike making a sandwich. The plants roots are pressed gently into the clay, and the top, growing crown is left emerging. Finally, another rock is pressed on top, sometimes with a bit more clay (mayo) and voila, you are done.
We all enjoyed making these alpine sandwiches, and then placing the assemblages into sand and gravel, which filled our troughs that we brought. Then, smaller plants, some rooted into pure tufa rock, are places around the structures we made, and finally top dressed with gravel.
Trough are a traditional English method of cultivating certain more challenging high alpine plants which prefer particular conditions such as scree, crevice or tight rock cracks, where they often grow and mature into tight, hard, bun-like structures, or, simply remain small. Although these plants demand exacting conditions, often a complex combination of fast drainage, constant moisture and frigid winters with no thaw, fast snow melt, permafrost, etc, alpine plants are becoming more popular with people who are concerned about the environment, for they are more endangered than ever, with threats of global warming, and ski areas being relocated higher in the alps and world wide, the declining phenomenon of permafrost in Alaska, and other environmental threats from the encroachment of humans into fragile habitat, if you are looking for a true 'green' statement that really means something, an alpine trough garden may be something to consider. These are not easy plants to get, or to grow, but once established, are rather care free, which is surprising, even to me. A perfectly planted trough can remain untouched for years if sited well.
This workshop introduced many of us to a new method of growing these fussy plants. The method is just about the exact opposite of how the world of rock gardeners have traditionally cultivated these plants, so sit tight, and listed. These hard, limestone encrusted Saxifrages and alpine gentians and primula which typically would be grown in a gravelly, mix of perlite, rock chips and soil, are instead, planted in wet clay. That's right, wet, sloppy, clay. This is the odd part of this method, - the clay, since it seems counter-productive to what one normally uses to pot alpines in, mainly, and alpine mix which is fast draining, with a little organic material. But when one thinks about the science of it a bit more, you can see the logic. Many alpines grow best, to character, dense and tight buns, when grown in pure tufa or limestone rock. Their tiny hair-like roots can move between the channels in the rock, and the plant grows hard and dense. Clay, when surrounding the roots, is mostly limestone elements and particles, with enough grog and chip to still move water through, but only when not fired (think clay pot, when wet), It is both porous and solid. I assume the clay soil once dry, never becomes mud again, but simply sponges water in a capillary action. And since the volume of clay is small, the mass never really exposes its surface to large amounts of water, since the clay is basically filling a crevice, and not a pot. Gravity and capillary action drays water up and down, and in this 1/4 -1/2 inch sheet of dry clay sandwiched between to porous slabs of rock, the perfect temperature and moisture levels are maintained.
Of course, we still need to see results, so stay tuned. But the pieces I have of pure tufa, in which silver saxifrages and Primula allioni are growing in, are 2 years old, and in perfect, hard, character, as if growing on top of the Alps. And, they are in full sun, in troughs, which I rarely water, if at all in the summer, and are exposed to all the winter snows and cold a New England winter can toss at them.
I know, it's a little overkill for a kitchen sink ( pardon the dirty stock pot), but with all of the rain we've been having, the cyclamen make it in again, even though these lost alot of flowers in the rain, they are still starting to bloom. Two more weeks, and the window will be full, as will the walk outside of the greenhouse, since I brought the pots all outdoors to get a good, soaking rain to start them into growth.
In this season of transition, the first cool nights, hot days, autumnal rains, bulb plants from the Mediterranian and South Africa begin to emerge from thier summer rest across our planet. It's one of the wonder of the plant kingdom. Cyclamen species are particularly seasonal, as such, most species are begining to emerge in the forests around Rome, in the gardens of those living in the northern hemisphere, and on the Greek Isle of Rhodes, where, the leaves of Cylamen graecum are surely being picked for eating. Yes, eating. hmmm Check this out.
OK, I know, strange to many of us but I happened across the site History of Greek Food, and here is what they have to say abour our precious Cyclamen graecum leaf thanks to Blogger Rachel Laudin.
“In ancient years the cyclamen was especially known for its medical virtues (it contains a powerful purgative poison). Its tuberous Rhizomes (thickened roots) have cyclamin which is a toxic saponin, so never try to eat them. The leaves of Cyclamen graecum have a bitter- sweet taste.
The best known florist’s cyclamen, Cyclamen persicum, is an important edible wild plant in Iran and Palestine. Its leaves are also cooked filled with rice, minced mutton meat, spices and eaten with yogurt (Palestinian Za’ matoot, Iranian dolme). I do not know if the leaves of this species have different taste.
However, the Greek cyclamen recipe is old and almost forgotten. In fact, the use of local Mediterranean food plants stands at a crucial point. As you know, Eastern Mediterranean communities were very much centered around cultivated and wild food both for subsistence and profit. After World War II the consumption of wild plants and seeds changed following the socio – economic changes. Unfortunatelly the amazing traditional knowledge regarding wild plants resources has not been infused to the young generations and I wonder if it already is on the brink of disappearance.”
A first for me, A pot of Notholirion thomsonianum, of course!
Oh, to live and garden in the North West.......someone please find me a job here!
A basket of select miniature Narcissus by Cherry Creek Daffodils, at the first day of the plant sale at the NATIONAL ROCK GARDEN SOCIETY'S WESTERN WINTER STUDY WEEKEND.
It's Friday, and people are arriving at the Double Tree Hotel here in Portland Oregon, and rushing out to the parking lot where there are in impressive about of plant vendors with tables of the most incredible plant material that any hortiphyle can imagine. Gosseler Farms, with rare shrubs, magnolias and perennials, Cherry Creek Daffodils with amazing miniature daff's all in bloom, Bovees Nursery with Vyreya and Rhody's, Siskiyou Rare Plant Nursery, Mt. Tahoma Nursery, Hedgerows Nursery, basically every catalog I have sitting on my coffee table at home, has a table out there.....what was I ever thinking bringing myself to a west coast plant conference, and believing that I would leave empty handed! Actually, I did bring an empty suitcase, just in case. It's full, now!
A potted Fritillaria bithynica in the plant show.
I am so impressed with the growers here in the N.W. Of course, thisis Frit country, but the members of the host chapter of NARGS, the Columbia-Willamette Chapter of the North American Rock Garden Society really have their, um...Frits together on this weekend. The speakers, the plant vendors, the location, even though I keep being told that the best NARGS chapter in the world in apparently the Rocky Mountain Chapter ( someone still needs to prove this to me!), this host chapter has really raised the bar on how to kick off a weekend for us crazy plant people. I can't wait to see what's next. The plant show looks like an AGS show, in England. Very impressive.
Tis the season for Cyclamen, and I don't mean those blousy, cabbagy, foil wrapped florist Clyclamen available at your local supermarket, although, they have their place ( they are hybrids of Cyclamen persicum, and the pure species form is very lovely if you can find it), but what I am blogging about here are the other species of Cyclamen, which are just beginning to emerge from a long summer dormancy world-wide, blooming in cold greenhouses, woodland gardens and on windowsills in the cold, autumn air.
Botanists have described 20 species of Cyclamen, and at first glance, they may all look very similar but with a little knowledge, one can see very distinct differences, mainly the foliage size and pattern, but also flower size and definition, as well as blooming time. The season begins in late August, where woodlands in the UK and in the wilds of Turkey, Greece and the Middle East, cylcamen emerge bringing the un-expected color of PINK to autumn. The fact is, pink is indeed a fall color, since nature has designed Cyclamen to bloom within blankets of brown autumn leaves on the forest floor.
In greenhouse, the season starts in September with the blooming of the more tender Cyclamen, C. africanum, followed by the fussier Cyclamen graecum. Even though Cyclamen hederifolium is hardy here in New England, I have yet to try it although I am assured that it will live, especially in those conditions which is loves, mainly under deciduous trees, where the bulbs, which sit on the surface of the soil, can go dry during their summer dormancy. Cyclamen coum is also supposed to be hardy here, but I prefer to keep this tiny gem in pots in the greenhouse, where it can self seed everywhere. I now have many Cyclamen species coming up everywhere in pots. At one time, I thought Cyclamen where challenging to grow, especially from seed. But the solution was easy - get fresh seed, which may sound easier than it is - seed available in seed catalogs and seed exchanges is already dried out. Once dry, Cyclamen seed is difficult to get germinated. But my own fresh seed ( by fresh-I mean hours old) is potted as soon as the seed capsules are ripe in June, and the pots are left unwatered until September, but apparently there is enough moisture in the soil to keep the seeds alive.
Alpine plant catalogs frequently carry some Cyclamen species, and I encourage any of you living in Zones 5 and up, to try some of these out doors, or certainly in your cold greenhouse. Having plants that start growing and blooming in the autumn and continue through the winter, makes this season as exciting as Spring all over again.