Saturday, October 30, 2010

Not to panic!

Hard frost came last Tuesday night and Wednesday, and though Indian summer has returned and it's been toasty today, the warmer nights aren't going to last forever. (I confess, I dragged in my favorite container with begonias and coleus it a reprieve for a while). The gardeners at Denver Botanic Gardens are thrilled: busy yanking the last tired annuals and getting around to winterizing. I have always been somewhat dismayed by their ghoulish yearning among professional gardeners for an early frost: somethings never change. I cling to the growing season. But, not to panic! Nature isn't really dormant in winter as all wise gardeners know: the next month or two are really the best time for many things. Geraniums, for instance, have yet to become truly ignited: they provide some of the best fall color in perennial borders and rock gardens after all. And grasses are really in peak splendor right now.

I took the picture above recently at Roxborough State Park, one of the many super state parks that garland Denver--and possibly my favorite. The red rocks of the Fountain formation form ramparts much like they do at Garden of the Gods or the Flatirons above Boulder only the access is trails. The panic grass was growing next to the parking lot: Panicum virgatum has become one of the bulwarks of the ornamental grass movement around the world (which in Denver--which should be the grass capital of the world!--usually consists of massive armies of Calamagrostis acutiflora 'Karl Foerster'). Very occasionally in a specialist gardener's yard you will see a clump or two of 'Heavy Metal' or some other Eastern selection of Panicum...but I have never seen anyone grow our native form, which presumably would be much hardier. There is so much to be done horticulturally in our wild and wooly steppe climate!

I will include another picture or two from Roxborough on the hike I took with my daughter when she was visiting: I need to go back down there soon!
Turkey foot (or big bluestem: Agropyron gerardii) had already turned: this is one of America's great grasses. I can't think of a private garden in Denver where it grows, although we have it all over Denver Botanic Gardens...

The scrub oaks were beginning to color a few weeks ago: many have probably lost leaves by now, but the oaks in Denver are just starting to turn (they are always the last trees to turn). Aaah: I must go back soon and see what's happening this month!

Wednesday, October 27, 2010

The other autumn crocus

The pleasure one derives from one's garden is often lopsided: I can look calmly over a vista with hundreds of showy mounds and mats in the border or rock garden, but when Crocus banaticus (above) produces a single lonely flower, I get really excited. I have grown it several years so far, and keep hoping to see signs that it really does spread and propagate freely as the books promise. It is a rare denizen of eastern Europe where dozens of distinct color forms including white and deep violet have been selected. What a pleasure it must be to tread the Danubian forests where this is said to grow by the million. I am sure that would be thrilling, but so too is seeing this fluted blossom with its iris like form (hinting broadly as to the family affiliation)...

I have grown Crocus nudiflorus for nearly three decades. It would appear and reappear every few years in the Rock Alpine Garden, but my frequent planting and replanting there probably led to its demise. A few years ago Jane McGary provided me with several corms and these seem to be happy in their new home: no sign yet of their sending out runners and proliferating. I recall seeing a picture of a moist meadow in the Pyrenees once with thousands of these goblets. A half dozen in my rock garden are every bit as delightful to my eyes. Its rich violet-blue color is a sight for sore eyes in the autumn: it has been sending up fresh flowers for most of the last month with no end in sight despite light frosts. Don't you love the way the stigma casts a shadow both inside and outside the floral segments?

Denver Botanic Gardens has impressive stands of Crocus speciosus, C. goulimyi and C. pulchellus this time of year: they have proliferated there over the decades, and have inspired a lot of home owners to incorporate these indispensible autumn flowers into their gardens. Unlike most of the larger Colchicums, their grassy foliage is not much of a nuisance when it emerges in the spring. And their luminous flowers light up the fall. A half dozen other species are gradually acclimating to this or that corner in my garden, but thus far, these two distinctive species provide me with pleasure utterly out of scale with their diminutive size. Speaking of diminutive, the tiny cranesbill at the base of C. nudiflorus came to me from Mary Hegedus as Geranium aff. nanum: know anything about that? It is cuter than the proverbial button! Aaaah. With little treasures springing up around me through the year, life is very sweet!

Monday, October 25, 2010

Toad lilies on the brink...

Plantasia at Denver Botanic Gardens is glimmering right now with dozens of wands of Tricyrtis
, probably the commonest of these east Asian woodlanders: of course in the next few days (or maybe a week) hard frost will put an end to their show. I recall seeing these the first time over 40 years ago in the garden of Sam and Mary Ann Heacock (the preeminent gardeners in Denver over much of the 20th Century)...and maybe once or twice elsewhere in the interim.

I had fabulous luck for years with Tricyrtis latifolia in the Rock Alpine Garden, although one day it was overgrown or otherwise missing in action. And I grew the giant yellow, nodding bell shaped gem that goes by various names in Boulder as a child for many years.

It is amazing to me that plants so universal in bi-coastal gardens are so utterly absent from our local scene. Each year the display of this spotted beauties expands and improves, chiding me for not trying them in my own private garden...

If you are from Colorado and grow toad lilies, let me know: you will be in a very select minority!

Thursday, October 21, 2010

Garden ornamentation: pros and cons...

Just as cake is the excuse for frosting for some of us, gardens seem to have become an excuse for garden art. I can think of a handful of local gardens where art upstages plants (something hard to do for a plant nerd like me). Part of the reason I enjoy the Henry Moore sculptures at Denver Botanic Gardens is that despite their massiveness, the garden surrounding them are not upstaged.

Then there is this imp in Jim and Dorothy's terrific garden in West Denver (one of my very favorite gardens). This improbable totem pole is riveting. It is irresistible. I am so glad it is in their garden and not mine however: it shines like a beacon and calls forth. Look at that expression! Panic? Irritation? Despair? Fear? Self Consciousness? It is undeniably cute (in a ghoulish way) and I love it. But if it were in my garden I would burn it after a week or two: it epitomizes everything I go to the garden to escape. To each his own.

I have more than my share of little garden sculptures and ornaments tucked here and there: subtle, almost invisible. Gardens in my book are for plants first, me second, and everything else way down the list. Garden ornamentation: I enjoy best in other people's gardens. (I just visited Lauren and Scott Ogdens unbelievable gem of a garden and saw nary a sculpture: yipppeee!)

Tuesday, October 19, 2010

Nodding Lady's Tresses

Orchids have that allure: I hate to think how many ladyslippers have been destroyed over the years by zealous, would-be wildflower gardeners (come to think of it, I have a few on my conscience)...of course before we flagellate ourselves, let's remember for every rare plant destroyed needlessly for horticulture, tens of thousands if not hundreds of thousands disappeared for agriculture, cities, mining and other human uses and abuses that we all depend upon. Nevertheless...
It is delightful when an orchid proves accommodating. The 'Chadd's Ford' selection of the common lady's tresses of the Eastern States can be found at garden centers, which is where my original plant originated. I planted it rather dubiously five or six years ago. Today, there are dozens of those shimmering white flowers gleaming and glimmering throughout my little bog. I assume they are seedlings. I have not dug them up to see if any came from runners.In fact, it's the most successful plant there (if one ignores the profligate curly rush and some weedy interlopers...). I always worry a bit in August, since the shoots never look promising until the coolth of autumn when they shoot up and bloom for weeks on end. They are still going strong the second half of October.
These are not for xeriscapes, I fear: they like to grow in a boggy, wet site with lots of full sun. That's not a common garden condition in Colorado, but well worth creating.
Ironically, the two lady's tresses that grow in Colorado are probably much harder to grow: I was the first to press a specimen of Spiranthes diluvialis, a lovely waif described from Golden, Colorado where Stanley Smookler was the first to find it. This used to occur by the thousand at that site, although I have not seen it in recent years. It has now been found in many Western States, and has a very complicated geneology. It looks so similar to S. cernua that I keyed it out to that plant and thought I had a state record when I first saw it. I never imagined that it could possibly turn out to be a species new to science (the first of half a dozen I've had a hand in discovering).
One of my earliest plant memories was of seeing our Subalpine lady's tresses (Spiranthes romanzoffiana) intermingled with fringed gentians on the Flattops. I confess, I have tried to recreate that picture in my garden, but the darned gentians are harder to grow!
I love to watch the graceful way the flowers twist down the stem, exactly like a graceful long haired lady's tresses indeed! Sometimes I think we like the plant more because of its name!

Saturday, October 16, 2010

Nature's last green is gold

Of course, Robert Frost is right about the first green: but green turns gold again in the fall, and this autumn is shaping up pretty nicely right now. Green ash and even some cottonwoods are bright yellow around town, and the first Autumn blaze maples and Autumn purple ash are bright red and purple in the distance from my front room window. The Ohio buckeyes, which often turn orange and scarlet in September, are only now doing their thing...what a gratifying, late autumn. But the apple of my eye right now (so to speak: sounds better than saying birch of my eye) is the ten year old Himalayan birch that crowns the waterfall in the rock garden at home. It is a neutral green much of the year, but for a week in the fall it glows gold and justifies its pride of place. It's getting a tad tall, and I keep thinking I ought to take it out (its roots are probably wreaking havoc with the waterfall) but now the trunk is getting gnarly and white barked [see below], and it's forming a graceful shape that with a little shaping could be enhanced even further...maybe I need to invite Harold Sasaki or Jerry Morris over for lunch some day soon....

This year, for the first time, it has set a lot of seed. I collected an envelope full, and more is ripening: I wonder if it will be viable? There are no other birches that I know of in the neighborhood so theoretically it could be true (assuming the seed is viable of course)...if you look carefully at the picture above you can see the interesting dark seedpods, as well as next spring's flower buds in waiting. What a cool little plant...

I've had the thing so long...I grew it from seed from either Josef Jurasek or Mojmir Pavelka, collected in western China. I shall have to dig back through my records and see if I can get any more info: I don't believe they had a species name on it. It looks like a tiny microform of Betula utilis, although in size and habit it is much more like our native B. glandulosa--although much more delicate. Betula glandulosa in our mountains can often be a fiery orange or even scarlet: it would be fun to hybridize them, wouldn't it? I've not had much luck with miniature birches, so having this one is compensation. If you'd like a pinch of seed, just email your address to me at and I'll post you some.

Thursday, October 14, 2010

The hardy Othonna...

Some days are emblazoned in one's heart and mind forever. The first time I crossed Joubert's Pass over the Witteberg in the East Cape (in January 1994) has to be emblazoned forever in my mind: I'd already spent a few weeks sampling the glories of the Drakensberg mountains proper, and then suddenly I found a whole new suite of plants, many of them xerophytes, on this spur of those great mountains and I realized how much remained to be learned. There was a most swale filled with Kniphofia uvaria at the base of the pass far from its more Westerly distribution, and spectacular Gladiolus saundersii in the foothills, joined soon by the equally dazzling orange form of Gladiolus dalenii. Gigantic angel rods (Dierama robustum) where dangling and swinging like censers everywhere in the meadows. On the rocky summit I was stunned to find Anacampseros rufescens, Pelargonium sidoides and other shrubby pelargoniums and especially this treasure of a succulent composite, Othonna capensis.

On subsequent trips I found this on many other mountains further westward in the East Cape, all looking very similar to my first find. I suspect anything in cultivation with this name stems from one of the collections I made in 1994 or on another unforgettable trip I took with the late and much lamented Jim Archibald in March of 1997. Although several nurseries offer this, no one seems to think the plant is very hardy. I suppose because it is a succulent it is relegated to very hot dry exposures, which is not really to the taste of this bona fide alpine. Here it has thrived for years for me in my rock garden at home, on a south facing slope to be sure, but shaded much of the day by giant Scots pines, and with a drenching every few days during the hotter months.

It generally produces its first flowers in April and there is a sprinkling of bloom all the way to late autumn: this picture was taken in October, but I'll bet there will be some bloom in a few weeks in November even after some pretty hard frosts...eight months of winsome bloom, and a beautiful succulent mat the rest of the year. Not bad for this little waif from the White Mountains of the east Cape!

Sunday, October 10, 2010

The BEST Zauschneria

I am not always a diehard, sticking to my guns no matter what. But I still call shooting stars Dodecatheon (even though I know they are really primroses) and zauschnerias may really be fireweeds (not a bad name for them) but I figure if hummingbirds know the difference, so might we...So I persist in calling this Zauschneria septentrionale.

I am always amazed there are not more zauschnerias planted in Denver. Plant Select has championed Zauschneria garrettii, which blooms in June, July and August but is pretty tattered by now. It is undoubtedly the toughest and hardiest...and many years the later blooming californica and arizonica are often frosted...but Zauschneria septentrionale never disappoints. This terribly underappreciated plant comes from northern California, and possibly Oregon. It generally comes into bloom in August, but it is still blazing away in mid October this year (I just took this picture last Friday in the Rock Alpine Garden at Denver Botanic Gardens.) I think I got my plant from Carman's wonderful nursery in Los Gatos almost 30 years ago, and it has grown there contentedly ever since. The silvery white foliage is decorative long before the flowers open, but with its wonderful bloom (and tolerance of many garden soils and conditions) I would rate this plant very high indeed. Don't you agree?

Tuesday, October 5, 2010

Jewels of the rainbow

Iris ruthenica

Iris potaninii

People will insist on asking you (when they find out you make a living from plants) what your favorite flower is. Asking someone like me to pick a single favorite flower would be like asking Harpagon which coin he liked most: plant misers love all things green...but there is something about tiny iris that sets them apart.

I was astonished to find Iris ruthenica growing by the untold million last year everywhere in the Altai and Tien Shan mountains of Kazakhstan, from the fringes of the steppe in the foothills to above treeline on tundra. It makes mats a yard or more across that were studded with hundreds of those prismatic blue jewel like flowers. I have seen Iris ruthenica on the Yulongshan of Yunnan and know it makes it all the way to Ruthenia in Europe: and yet this is not a common plant in gardens. I have grown many forms. I have grown some of them in large quantities. One of the sad things of being an old gardener is you realize you have fumbled many good plants: those forms are largely no longer with me. I now make a point of propagating and planting lots of plants of this around so that I never lose it again. I am particularly pleased to have found quite a bit of seed of Iris ruthenica in the Siberian larch forests above Markakol lake in the Altai a month or so ago, so we will have plants one day from a known locality.

Iris potaninii (if it's not actually I. tigridia) is a bona fide alpine from Tibet and neighboring regions I have grown off and on for years. It seems to be settling down in my garden in this marvellous yellow form.

But the REAL miniature iris are all the dwarf Iriodictyon and Junos sections that one must plant this time of year. I have placed orders with three specialty nurseries to get even more of these prismatic gems. I am not going to tell you which ones or where I ordered them until they are delivered to my door (and preferably planted in the ground). I don't want YOU snatching my jewels! Half a year has elapsed since these last bloomed in the garden, which means their bloom season is now fast approaching! Winter is so much more tolerable knowing that it will chased away with a flurry of irises on its heels!

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