The Beautiful and the Unobtainable: Growing Alaska Alpines Outside
James H. Fox
(A version of this article appeared in the Winter 2002 edition of the Rock Garden Quarterly, Bulletin of the North American Rock Garden Society)
Before showing slides of Alaska alpine plants to groups of rock gardeners I tell them to look at the pictures carefully - this will be the best they'll ever see an Alaska alpine outside of Alaska! Moving a plant, whether by seed, cutting, or rooted plant from a latitude of 62 or 70 degrees north to one below 45 degrees north is nothing short of a serious shock to a set of genes evolved over thousands of years to endure short, cool summers of intense, near continuous sunlight, and long, dark, debilitatingly cold winters. Even when I tried to grow plants from Nome at Palmer (just northeast of Anchorage) I had limited success. The plant often grew well but it didn't flower well, if at all. Since moving to Seattle four years ago I grow few Alaska alpines, being too busy exploring the plants from other parts of the world I couldn't grow up north. I have visited gardens and talked to people in Washington and elsewhere in the U.S., Canada, and Europe who have tried Alaska alpines. A few patterns have appeared which I'll discuss in this article. I am particularly indebted to Rick Lupp of Mt. Tahoma Rare Plant Nursery in Graham, Washington, south of Seattle, who has visited Alaska several times in search of alpines and who has much practical experience in trying to grow them here. He has come to many of the same conclusions I have. It's always nice to quote someone as an authority who agrees with you. His experiences and ideas enrich these notes.
The patterns which have emerged from my experience and observations are these: the further north the origin of a plant the harder it is to get it to bloom or even grow. Seed provides the best chance for success. Cool temperatures - even if provided by bright shade - offer the best chance for success. Consistent winter dormancy is important but not absolute to survival. Slugs are a severe threat to plants evolved in a slugless environment which includes most of Interior Alaska, the mountain ranges, and the coasts along the Bering and Arctic Seas. An alpine house or a frame help, along with very good air circulation. Gothenburg Botanical Garden in Sweden, for example, uses a large fan to direct strong air over the alpine house beds.
When selecting a species to try it is important to know the area it comes from, some ecological areas offering better "hardiness" than others. In my opinion (I have lots of them), there are essentially six ecological regions/plant zones in Alaska to consider: the Aleutian Islands and Kodiak Island which are wet, cold, and windy; South-Central Alaska, which includes Cook Inlet and Prince William Sound to some degree - this area is temperate and forested with tidal and river flats to high mountains; Southeastern or the Panhandle, which starts from eastern Prince William Sound and goes east and south through Juneau, Sitka, and all the way to B.C. - extremely wet, limited snow at sea level, with fjords and high mountains; Interior Alaska and the Alaska Range, which includes Denali (Mt. McKinley to some) - this is an area of extreme dry cold and dry heat; the Seward Peninsula where Nome is, which has remnants of the Bering Land Bridge flora and some Russian Far East flora; and finally the North Slope from the Brooks Range north to the Arctic Ocean - this is the area of the Midnight Sun and several months’ long night and the plants are generally tiny alpine or tundra species.
While many species are found in many or all of these areas those from the southern and wetter areas perform best in latitudes further south. Rick Lupp and I agree that the areas with the most potential are the Aleutians, Kodiak, South Central, and the Panhandle. Unfortunately the best - read "most coveted" - plants come from the mountains of the Interior, the Seward Peninsula, and the North Slope: such little treasures as those from the Douglasia, Androsace, Campanula, Claytonia, Gentiana, and Erigeron genera. These plants are used to extremely long summer days with intense light and cool temperatures, and long, dark winters buried beneath dry and insulating snow - conditions no self-described slug could endure.
Over the years I and others have sent cuttings and plants from our Alaskan gardens to people around the world who have had limited success growing them on. Most of the plants to survive were grown from seed. Seed from known wild sources is the best. Rick Lupp has germinated many, grown them on, and even produced a flower or two. The genetic variation in a Over the years I and others have sent cuttings and plants from our Alaskan gardens to people around the world who have had limited success growing them on. Most of the plants to survive were grown from seed. Seed from known wild sources is the best. Rick Lupp has germinated many, grown them on, and even produced a flower or two. The genetic variation in a packet of seed allows for one or two seedlings to do better in your conditions, setting up the foundation for an adapted, local, strain. Stanley Ashmore of Palmer, Alaska, planted hundreds of thousands of Meconopsis seeds over a decade. The few surviving seedlings bloomed, their seed was planted out, and the process repeated until he had several hardy strains. Certainly it is very difficult to get thousands of seeds of say Douglasia ochotensis, but the idea is the same. Perhaps the Alaska Chapter could be encouraged to mount a seed expedition to the Alaskan wilds.packet of seed allows for one or two seedlings to do better in your conditions, setting up the foundation for an adapted, local, strain. Stanley Ashmore of Palmer, Alaska, planted hundreds of thousands of Meconopsis seeds over a decade. The few surviving seedlings bloomed, their seed was planted out, and the process repeated until he had several hardy strains. Certainly it is very difficult to get thousands of seeds of say Douglasia ochotensis, but the idea is the same. Perhaps the Alaska Chapter could be encouraged to mount a seed expedition to the Alaskan wilds.
As a rule, a soil mix containing a large portion of grit to peat or a lean soil produces the best results. The plants need food which can come as compost or fertilizer, but few need a lot - primroses fed by Yak or Musk Ox dung aside. Rick uses nine parts sand, five parts peat, and four parts pumice as his standard mix. In Washington I use a mix of four parts pumice to one part manufactured potting soil containing compost, peat, and perlite. In Alaska I used a similar mix 2:1 because the weather was drier there.
The family with the best success according to Rick and others is Ericaceae, followed by shrubs in general. I first saw Ledum palustre growing in a garden at Sally Allen's in Seattle. It was a floriferous clone, compact, not leggy like in the Alaska wilding. She grew it with Vaccinium, Gaultheria (and the then-Pernettya) under evergreen trees to provide shade from the hot sun. A piece of this plant now grows in Alaska in a couple of gardens and is deserving of a name if it doesn't have one.
Cassiopes do well in Rick's garden, though, he says, growing slowly and with less flowers then the ones he's seen in the wild. Gardeners in Scotland do better being further north and cooler. Loiseleuria procumbens from Alaska grows well in several Seattle gardens and alpine houses but blooms sparingly, while European clones flower much better coming from a more southern latitude. Rhododendron lapponicum survives but I have no reports of it flowering here. In Alaska I grew it quite well in a soil with sand and pea gravel and very little peat. Its blooming habit was extremely odd, blooming prolifically on one half of the plant several weeks after the other side produced a few blooms. Year after year it staged this Jekyll-and-Hyde performance. Rhododendron camtschaticum is another two-sided plant, being divided into two subspecies - ssp. glandulosum in Nome and the Russian Far East and R. c. ssp. camtschaticum along the Aleutians and Kodiak and a few other southern spots. The latter is the one in cultivation. I know of no cultivated plants of R. c. ssp. glandulosum , which is a runner, a shorter plant, with large flowers opening flat or slightly reflexed. The growable R. c. ssp. glandulosum produced the coveted white form which derived from a single plant found on Kodiak Island and put into the green-fingered hands of Aline Strutz who sent out thousands of seed around the world until various strains established themselves in North America and Europe. Grown in a gritty, peaty soil in coolth, this variety and its parent subspecies will grow well, albeit slowly, and flower on a shrubby plant with large, slightly cupped flowers. It is a charmer.
Vacciniums from Kodiak are known to bloom and grow well further south, though not as well as V. viti-idea 'Minus', but the even tinier forms from Interior Alaska grow without ever blooming.
Even the temperamental Diapensia lapponica settles down to southern living grown from seed, though Henrik Zetterlund told me he was able to root cuttings. Reports of a pink form are many, but without much foundation in my experience. I watched a colony north of Palmer for several years which showed pink when I first discovered it, but the color wasn't stable, simply a result of cold, hard rains during flowering season which appeared to bruise the petals causing them to blush.
"Dryas are pretty darn good growers" according to Rick Lupp. Why shouldn't they be - the genus is circumpolar so it has to be adaptable. It's a symbol for the Scottish Rock Garden Club. So why bother with the Alaskan ones, you wonder. It's simple, there are many fine forms in Alaska, it is easily grown from seed or cuttings, and one doesn't need a visa to visit the state. I found many different forms and hybrids in every mountain range and glacial stream I explored in Alaska. Ones with tiny dentate leaves, others with large silvery foliage; some with flowers of ten to twenty petals - even a double spotted in Nome by Jerry McEwen; more with creamy colored, beige, or white flowers. None yellow, though Rick recently found a natural form of D. sudermandii which is distinct. His experience with the argentea form of D. octopetala is that it roots with some trouble, grows, but doesn't bloom. From his plants of D. integrifolia he's distributed lots of seed, though the blooms are sparse. D. drummondii does well.
For many years I sent out cuttings, and some plants, of various hybrids and forms of willows gathered from around the state. Only Alaskans and other high-latitude gardeners could root them and grow them on. For other gardeners it was clear the summer's heat was too much for the cuttings, sending their metabolic rates sky high, fatally exhausting them before sufficient roots could form. Rick tried seed, too, but the seedlings were too tiny and expired once temperatures went above 70 F for any length of time. However, plants rooted and established in Alaska survived quite well when sent out. An enterprising Alaskan could do a fine service rooting on Salix for the rest of us. As a rule, Rick found Salix reticulata forms and hybrids performed best for him in Washington. Unidentified willows with tiny reticulated leaves, which I grew and sent to New Hampshire, survived, no doubt because of the cooler temperatures. The tiny and widespread S. rotundifolia and S. polaris do survive but do not grow well for Rick. There are uncounted beautiful and exquisite willow hybrids in Alaska - enough to entice willow lust in most any gardener.
Betula nana, another circumpolarist, does too well in Washington, becoming anything but nana, though a tiny clone Rick found in the Interior has remained small in bright shade grown in a pot. The birches, like the willows, have few morals when it comes to pollination, which can be very fun for the gardener interested in new forms and shapes, but not for the purist with a rigid sense of species. Several beautiful hybrids result from natural crosses between the dwarfs and the tree birches.
A more mixed group of plants and performers are the Perennials which I'll discuss in no particular order or preference and certainly not comprehensively!
One of the most appealing is Campanula lasiocarpa 'Talkeetna' a form Rick selected and sold for many years and which should still be in the UK. It won prizes at many shows, but is very difficult to maintain and keep happy, even hard to bloom at times. Rick kept it cool - conditions perfect for slugs which, along with heat, eventually killed all of Rick's plants of this clone. In Alaska, however, I didn't keep the species - it kept me. Once in the rock garden it ran with abandon, swamping other choice plants and, I suspect, any slug that dared get close. I did find a semi-double, a pale blue form, and saw a photo of a white one. The tinier, but still rampant C. uniflora didn't succeed for Rick either, though I grew it, but even in Alaska gardens it was a shy flowerer. But if you try Campanula rotundifolia you'll have no troubles - if you keep the slugs away (I have tremendous success with the anti-slug products made of iron phosphate. Small amounts nearby keep the slugs away, the product hasn't attracted any of the pets, and it's simply fertilizer). There are many lovely forms of C. rotundifolia in Alaska with purple-blue to pure white flowers, some of the bells are shallow and wide, others huge and long, or tiny and numerous. It is easily grown from seed or small divisions. Then there is C. dasyantha (C. chamissonis Federova in Hulten). Found in the Aleutians, it has large purple tubular flowers and a vigorous habit. It grew well in regular garden soil with good drainage or in scree conditions in Anchorage and Palmer gardens. But the treasure is Campanula aurita - not at all bell shaped. I found it on the road to Eagle, little clumps in rich screes with flower stems to five inches topped by purply-blue, wide-opened, five-spoked, somewhat reflexed flowers. It grew well in a rich gritty soil for several years in Alaska though no one outside the state reported any success with the seedlings or plants I sent them. Not even in Sweden where they should have grown well.
Parryi nudicale from seed does very well for Rick. He has been able to list it in his catalogue at times. It even blooms quite well though oddly it's not as fragrant in Washington as it is in Alaska. He grows it in his standard alpine mix, though the plant grows in moist peaty humus in Alaska.
In recent years, Papaver alboroseum has appeared in abundance on seed lists. When I first started growing alpines in Alaska over 25 years ago it was extremely rare and on the endangered species list. Bring in the oil explorers, however, and suddenly it was found on more mountain tops and ranges than could be counted - thus the sudden abundance on the seed lists. Grown in a very lean, gritty soil it stays compact with gray-green bristly foliage and beautiful apricot-pink cups that are white at the center. Any nourishment transforms it into a gross, leggy, impolite green with sickly beige-blushed flowers on floppy stems, reaching out to cross pollinate with any poppy neighbor.
The other Alaskan poppies were difficult for me to keep in my Alaska garden - their lovely translucent chalices of primrose, rich yellow, or greenish yellow lasting but a year or two before the plant died leaving no seedlings. Rick claims very poor success with Alaskan poppies, too. He's convinced it's the photo period difference which inhibits blooming. Some growers have tried high intensity lights in alpine houses on several different alpine plants with limited success - and immense electrical bills.
Of the many saxifraga tried in Washington only Saxifraga bronchialis ssp. funstonii does well. The Alaskan forms of S. oppositifolia, while tiny, dense, and floriferous up north, resent the heat further south. The European forms are better performers, as is Silene acaulis from the Alps. Rick did produce a blooming clone of Silene acaulis he named 'White Rabbit' from seed of a vigorous, long blooming white form I grew in Alaska called 'Chickaloon.' Again, the leaner the soil the tighter the growth and the better the flowering.
Gentians from anywhere provoke sighs of delight and wails of frustration. Alaskan gentians are no different, being prone to slug depredation, heat exhaustion, and a bad winter's sleep from freezes and thaws. The exquisite G. paltypetala survives in alpine houses in a gritty mix in Washington - and it blooms! Claytonia acutifolia will survive in similar conditions for a short period. However, Claytonia scammaniana is the finest of the spring beauties. Large, deep rose-pink flowers on short stems sit above little deciduous, succulent-like leaves. (Perhaps it was this Claytonia or some near-relative which commingled with a lewisia far back in prehistoric times to produce Lewisia tweedyi.) I grew this plant for several years from seed from Aline Strutz. It was a prolific little gem until it suddenly up and died one year - every plant and all its seedlings, in every garden - as if it, too, heard and heeded the bamboo death wail. As far as I know it has never been back in cultivation. It would please me to no end to be told otherwise.
The American Primrose Society Alaska chapter operates from the foothills of Southeast Alaska so I hope its members will soon be putting seed from the Alaska species into seed exchanges. Rick says Primula nutans is growable in Washington and is beautiful. It is a smallish plant to three or four inches with large pale pink or white flowers, appreciating a gritty and peaty soil. Outside Nome it grows by the thousands in the mucky river flats of the Nome River as it empties into the Bering Sea.
Further inland, along cold, mucky hummock banks of little ditches I found P. tschuktschorum var. tschuktschorum which produces its flowers around the top of the flower stalk. It didn't grow well in my garden, though I have read reports of it growing in England and have seen it on seed lists. The photos and descriptions of those plants however do not match what I saw as P. t. var. tschuktschorum, but of the very similar P. t. var. arctica which has a much wider and more southerly distribution on to the Aleutian Islands and southern Kamtchatka. (If ever there was a plant with a tongue twister of a name, this is it!) This correlates with something I've noticed about many of the plants shown to me in Europe as Alaskan which didn't have the look of the species or genera I'd seen in the wild in Alaska. Upon further questioning I learned that every one of these suspect plants originated in Japan or southern parts of the Russian Far East, though they are also found much further north in Alaska. These plants are better adapted to lower light intensities, less drastic photoperiod changes, and warmer winters. In Alaska we look for climates similar to ours and to the northernmost populations when exploring for new families and genera to try; those of you gardening further south should look to the most southern populations of Alaskan genera for the greatest potential for success.
Primula cunefolia is a good example of a Japanese population doing better in gardens. For years I tried to grow the Alaskan species and subspecies in my garden there, but with poor results. Seed from Japan, however, grew and flowered extremely well for me for many years in Alaska and for growers further south.
The primula relative Dodecatheon will grow well further south. Many of the varied clones of D. pulchelum survive in the Lower 48 if kept from slugs. A fine form with narrow, corkscrew-like petals I found was still growing in the garden of the Palmer Visitors Center Garden in 1997. All of the shooting stars like a good garden soil. Dodecatheon frigidum prefers a gritty alpine mix and does well for Rick but isn't easy, he reports.
Growing with the shooting stars in the wild is Iris setosa, which is counted as a success story in good garden soil kept cool and moist. In the wild the flower colors range from white to black-purple with every shade of blue or purple imaginable, and with white, yellow, or black eyes. The so-called Iris setosa ‘Nana’ is not I. setosa but the Atlantic species I. hookeri, considered by some to be a race of I. setosa but very distinct to my eye. (Some think otherwise, but having grown them side by side, I find many differences. Nor did they cross in my garden when growing side by side.)
The stinking or chocolate lily Fritillaria camschatcensis also grows in the same areas as the Dodecatheon and Iris and will do well in the garden if kept moist. I never saw a yellow one in Alaska - tracing all reports of such back to sightings in Japan - but I do have clones which are greenish-tan, and a yellow-tinted suede color. A well-draining mix of 1:1 pumice and compost keeps it happy in pots in Washington. These clones produce similar flowers from seed.
The lovely Geranium erianthum has done fine in well-drained garden soil, but most of the plants I've seen are not of Alaska origin - except Rick's. There's a lovely variegated form I found called G. erianthum 'Master McEwen'. Its leaves are chartreuse with light orange edges, especially pronounced in the spring. So far it is passing on this coloration to several hybrid seedlings with other nearby geranium species. The flowers are the typical mauvey-blue.
The Alaska arnicas impressed Rick most on his first trip to Alaska, and Alaskans sometimes call them the arctic sunflowers. They are growable outside of the state but are slug magnets, even on high shelves in alpine houses. Another good doer and slug attractant is Boykinia richardsonii. It will germinate easily in a peaty-gritty soil and grow well if kept cool and moist.
The Tiny Alpines
The Oxytropis are somewhat successful as alpine house plants and in sand beds, but all of the alpine species of this genus are hard to grow well according to Rick and others. So if you have success with them in general you should do well with the Alaskans.
The quintessential alpine jewel for me is the shrubby Artemisia senjavinensis, a tiny silver, bun-rosette wormwood. It grows well for Rick in a gritty alpine mix in the alpine house. Plants from seed were recently divided and cuttings taken with little success. Three of five plants died and only one cutting rooted. But it is growable from seed. Cuttings I distributed from my Alaskan plants came to no success. I suspect a bit of serpentine gravel or stone might improve its growth in a pot. It grew in rock which looked suspiciously serpentine north of Nome.
Eritrichium aretioides is a good doer especially when compared to the Rocky Mountain E. nanum, though it doesn't bloom as well as the latter. I admit to limited success growing any of the Eritrichiums, and content myself with wild sightings of it and its various color forms along Eagle Summit in Alaska. (It's important to note that Eagle Summit and Eagle, two sites I mention, are two different places in Alaska.)
By now you have begun to notice the same patterns I have: many Alaska alpines grow decently but flower sparingly, with that in mind it's now time to talk about the most coveted plant in Alaska according to all the requests for it I and other Alaskans receive yearly: Douglasia ochotensis. I have one piece of advice which will guarantee a well-blooming plant of this jewel of an alpine. Fly to the Arctic Sea coast of Alaska and take a picture of it in bloom. Recorded blooms on cultivated plants number only four! Two in Alaska and two in Britain. Seed is rarely available, but does germinate well and grows slowly into tiny, tiny buns which the slugs love. Rick has "had 50 to 60 odd plants over time and I lost them all!" A candid admission we should all profit from. No Botanic Garden has publicly admitted flowering a plant, not even Kew with its refrigerated bed and high intensity lights in the alpine house. A lesson to be learned. Rick's recommendation is to grow Douglasia montana - it is a lovely plant and it blooms!
Their near cousins Androsace chamaejasme ssp. lehmanniana does pretty well in the open scree for Rick and in his sand bed too, if not too hot. It even blooms and is an excellent alpine house plant.
I have found Cypripedium guttatum in the alpine regions of Interior Alaska as well as the forests in South-Central. It also grows along the Aleutians into the Russian Far East and Japan and into China. In Alaska it grew quite well in gardens, spreading by underground stolons and persisting in tall grasses for decades. In the wild it grew on dry wooded slopes or in peat bogs in full sun. It is prone to a fungal attack in more southern climes, but not fatally. The plants are most affected as they near natural dormancy. Steve Doonan says he has had success in the garden giving the Cypripediums a little extra nitrogen as a dilute solution. This matches what I've seen in Alaska with Cypripedium passerinum which is extremely difficult in cultivation. Near Palmer I was shown a huge population which had sprung up on an old gravel logging road a few years after fungi had popped up in the road. Along the road edges grew Populus tremuloides which is a nitrogen fixer as were the fungi. One or two nursery labs are producing flask grown seedlings of so many of the Cypripedium species that it is economically and morally worth the effort to try and grow these otherwise hands-off beauties.
It is very difficult to give specific advice on growing any alpine plant to a group with such diverse membership and geography, but if you start from seed, especially from the southern extreme of a given population, use a lean mix and provide cool temperatures with lots of light, and can keep the slugs at bay you are much closer to success. If you successfully grow a similar plant to an Alaskan one then by all means try the Alaskan species with the same conditions.
In the end Rick and I agree on one surefire bit of advice - go to Alaska and take pictures. The slugs don't seem to bother them - yet.
Copyright by James H. Fox
Jim Fox, originally from Alaska, lives in Washington State where he works in a nursery, consults, speaks, and writes. His book How to Buy the Right Plants, Tools and Garden Supplies is available from Timber Press.