Scottish Rock Garden Club Forum
General Subjects => Alpines => Topic started by: cohan on December 17, 2009, 02:58:15 AM
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i'm not positive i have the right terminology, but near enough anyway:
i'm looking for inspiring examples of what i can do with my available stone, which is a highly mixed remnant of the glaciers in this area--which usually crops up to varying degrees in fields etc, ranging from gravel size to lots of comfortable two-handers, on to (occasionally) some boulders only for the skilled or well equipped to move, and in my case, a few pieces that i can just move, without developing a new skill set...
they are all smooth edged, like river rocks, (not angular recently broken, generally, but stones that have likely been moved hundreds of miles or more by the glaciers) with lots of quartzite (weathered to various shades of off white, tan etc), granite (the red and white sorts, mainly) some chunks of sandstone (which are flattish, and distinct enough i may save them up for separate use) and bits of other things..
take a look at some shots i took near the columbia icefield, and you'll get an approximate idea of the mixing of stones, my mix is likely even more diverse..
http://www.srgc.org.uk/smf/index.php?topic=3923.60
starting at reply 67;
i guess this is more or less a scree or perhaps more moraine setting? i could do something similar in my garden, though i am thinking of more of the larger stones nearer together, with areas of more gravel around/through (the most common gravel here, eg on the roads, is a similar mix of stones, in fact you can walk along a gravel road here and find all sorts of interesting pieces)..
i already have some of my own ideas-debating the degree of randomness of distribution (of course totally random in nature in this type of stone deposit) vs groupings of similar types and sizes of stones-probably will do some of both..
but i'd like to see any existing-stone intensive- rock gardens that have been made with this type of stone, or any interesting natural plant communities in this sort of mixed stone..
i've been searching the internet and this site, but haven't yet found anything like this...
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Hi Cohan, we are on a kind of glacial till too, limestone in our case. The stone was mostly buried under thin topsoil but there is just further broken stone underneath, from rounded boulders down through pebbles to sandy material. Drainage is excellent. The central feature in our garden is a sort of dry streambed cum path, in which are planted numerous alpines. We simply took off the topsoil and distributed the more photogenic larger stones on top of the subsoil. Silver and kabschia saxifrages do extremely well planted so their roots go down between the pebbles. Mossy saxifrages are seeding around nicely too, even in full sun - their roots are under the cool pebbles. I will try to post some pictures.
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Hi Cohan, we are on a kind of glacial till too, limestone in our case. The stone was mostly buried under thin topsoil but there is just further broken stone underneath, from rounded boulders down through pebbles to sandy material. Drainage is excellent. The central feature in our garden is a sort of dry streambed cum path, in which are planted numerous alpines. We simply took off the topsoil and distributed the more photogenic larger stones on top of the subsoil. Silver and kabschia saxifrages do extremely well planted so their roots go down between the pebbles. Mossy saxifrages are seeding around nicely too, even in full sun - their roots are under the cool pebbles. I will try to post some pictures.
thanks, darren, i look forward to seeing some photos of your garden; although i have little to no limestone (possibly dolomite pebbles..) i think the look of a streambed is one of the things i may be able to do..
my case is a bit different, in that we also have a deep soil and subsoil, mostly clayey, with a variable grey wooded soil on top on most of the area i will garden(more humusy areas in wet spots etc, but thats not where i am gardening, mainly)--the stonier till is not a surface feature right here (there are occasional gravel hills in the region, but not on my land, unfortunately!)..
so what i have is a fair pile of rocks brought to the yard over the years, mostly removed from cultivated fields-they tend to work their way to the surface, and some fields need repeated stone gathering; digging in my soil will produce occasional stones, but not enough to be of any use..
using what is at hand, i will probably shape the soil itself (by removing soil from areas to be made lower/wetter,and piling in areas i want to be higher i hope to create moister zones and higher 'peaks'!) with rocks worked into and above that..
i know that doesnt exactly follow standard rock garden construction, but the idea at this point is to use existing materials as much as possible for reasons of economy; excess water is rarely an issue here, and the beds in question are at the higher and drier end of my property, so while i will fiddle more with the substrate in particular planting zones of the rock garden, i'm not worried about having a lot of clayey soil below it, and i'd rather mainly keep the stones i do have in the visible zone and just below where the plant roots may need them...
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Hi Cohan:
We are located in the Lower Fraser Valley and garden on what geologists like to call "boulder clay" - basically a glacial deposit of clay with irregular slightly rounded rocks much as you describe. Our solution was to build our rock garden beds on top of the clay. We used mostly sharp sand as we have very wet winters, mixed with some peat to provide a bit of humus. Some of the beds are pure sand and the saxes and some Androsaces seem to like it.
Regarding rock garden design with boulders, my view is that much of the natural habitat of alpine flora is on talus slopes, glacial moraines and shattered rock outcrops with often not much evidence of stratification. So it is quite feasible to build a crevice garden using boulders where the emphasis is on the chaotic aspect of nature rather than a more formal sedimentary look. While the use of sedimentary rocks to resemble a rock outcrop is the standard and elegant method of rock garden construction, a natural rock garden can also resemble a talus slope or moraine, which are the primary natural habitats of alpine plants. We are fortunate to garden on a slope which makes it much easier to create a talus and moraine rock garden. Plus we have lots of boulders! Here are some photos of our front yard:
(http://)
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thanks for these examples, david..
certainly the plants are looking fantastic, they clearly like what you are doing!
so where exactly are you in the fraser-would that put you at around wet zone 7-8?
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Hi Cohan:
Yes we are in USDA Zone 8, not far from White Rock. A nice Pacific frontal system has just come in warming things up and drenching everything. While our winters are wet, summers are often quite dry but not too hot, so saxifrages do well here.
I originally tried to build a stratified rock garden ten years ago using our boulders but gave up. Then I noticed that most alpines in the mountains don't grow in stratified rock anyway - so that gave me the excuse to build a chaotic rock garden. I condensed my thoughts into an article for the NARGS Quarterly a couple of years ago. A copy is attached.
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Hi Cohan:
I originally tried to build a stratified rock garden ten years ago using our boulders but gave up. Then I noticed that most alpines in the mountains don't grow in stratified rock anyway - so that gave me the excuse to build a chaotic rock garden. I condensed my thoughts into an article for the NARGS Quarterly a couple of years ago. A copy is attached.
thanks for the article-i'm ornery enough to do my own thing even if i didnt find anyone else doing it, but nice to see some examples...lol
i'd be interested in seeing the Gwen Kelaidis gardens too, any idea if they would be online anywhere?
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Glad to hear someone is as ornery as me. I like to experiment to see if something different will work. Much of what is written in text books is regurgitating practices from the past without much new insight. Reginald Farrer was a great guy but he has a lot to answer for!
The only place I have seen the photo of the Gwen Kelaidis berms was in the NARGS book: Rock Garden Design and Construction published by Timber Press. If you Google the book title you get a Google Books result and you can click through to the Contents and navigate to the chapter by Gwen Kelaidis. The photo is on page 72.
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Glad to hear someone is as ornery as me. I like to experiment to see if something different will work. Much of what is written in text books is regurgitating practices from the past without much new insight. Reginald Farrer was a great guy but he has a lot to answer for!
The only place I have seen the photo of the Gwen Kelaidis berms was in the NARGS book: Rock Garden Design and Construction published by Timber Press. If you Google the book title you get a Google Books result and you can click through to the Contents and navigate to the chapter by Gwen Kelaidis. The photo is on page 72.
well, there are many many kinds of rocky environments, so why not many kinds of rock gardens?
the stratified type can really look great, but not realisitic with the rocks i have for now.. longer term, it would be nice to do a number of different things..
some cactus growers i know use straight road gravel--the type with fines and clay mixed in--and i think this would be a great material as a 'berm' /moraine, in particular for many species from west and south of here in dryish environments...
i'll keep my eyes open for the book...
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The Western Winter Study Weekend is in Medford Oregon the first
weekend in March. One of the open rock gardens during a previous
study weekend there would interest you - on a ranch, lots of spiky plants.
I assume it will be open again this time.
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sounds interesting.. i sometimes forget about the dry parts of oregon and washington, like b.c., i guess, wet coastal areas, drier interior..
i was just noting your average precipitation, which isnt as high as i expected it to be-if i'm remembering correctly, toronto's precip is over 800mm
-the town to the west of me (32km) is around 535mm total precip, and the city east of here (64km) is 482mm, so i guess i should be somewhere between. the precip goes down as you go east, away from the mountains..
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Cohan, here's a link to some from GK in Jane McGary's book, as David suggested above.......
http://books.google.co.uk/books?id=aHLFIGoERqIC&pg=PA71&lpg=PA71&dq=Gwen+Kelaidis+gardens&source=bl&ots=5cYx1nov3n&sig=K8-SZ7RQ5ejLCUJ020o-ZvvrutE&hl=en&ei=eEo_S77YO5_20wTHr9XRDw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBMQ6AEwAw#v=onepage&q=Gwen%20Kelaidis%20gardens&f=false
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You have a great looking rock garden David !!
I'm sure it provides the right habitat for lots of flowers !
I love it !
Thanks for showing !
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Interesting discussion - but please: what is a ' stratified ' rock garden?
Gerd
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Cohan, here's a link to some from GK in Jane McGary's book, as David suggested above.......
http://books.google.co.uk/books?id=aHLFIGoERqIC&pg=PA71&lpg=PA71&dq=Gwen+Kelaidis+gardens&source=bl&ots=5cYx1nov3n&sig=K8-SZ7RQ5ejLCUJ020o-ZvvrutE&hl=en&ei=eEo_S77YO5_20wTHr9XRDw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBMQ6AEwAw#v=onepage&q=Gwen%20Kelaidis%20gardens&f=false
thanks, maggi--you spoil me, i hadnt even got around to searching yet :)
gerd-- it refers to things like the popular crevice gardens, and other traditional types of design where the rock appears to be in layers
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Thanks for information Cohan, found your answer only now!
Gerd
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Just a point on geological terminology... "Glacial till" does not make a good substrate for alpine gardening (or for any other purpose that relies on permeability such as for drilling water wells), since it refers to a completely unsorted and unstratified mix of (primarily) clay with boulders and sand. If anyone recalls the previous discussion on permeability ("sharp" sand versus rounded and well-sorted sand), till has very low perm because the fine material fills the pore spaces between coarser particles (i.e. the sand grains and the boulders).
Anyway, a more suitable term for what you are planning to create from glacially-transported boulders would likely be a "glacial moraine". :)
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thanks for the clarification lori;
i wasnt so much thinking of till as the final product, but more the raw materials, though i will admit i didnt find really great working definitions...lol--most of the references i found online were snippets of books which i would probably need to actually read to get a better grasp of the terminology and some of the final processes involved in local soil/substrate creation :)
clearly the basis of the landscape here is glacial, though apart from gravel deposits (none on my place, unfortunately) i'm not clear on where the line is between what was dropped off, scoured away, and what was here before the glaciers-the point i forget about most--that there could have been soil here before glaciation which remained after? was it all removed and dumped back?
anyway, yes, i was thinking that moraines are closest to what i was thinking of as a finished product :)
would you say that till is what plants are growing in in places such as at the foot of glaciers? those that i saw near columbia icefield were all in more or less soggy soil, i think, not sure if they ever get dried out in mid summer--i was there in july, i rather doubt at that altitude there is much time between melt and new snow, and as you say, what 'soil' there is among the stones is clay, so not much drainage other than on slopes or pockets that are mainly stone (such as the moraines a bit farther back, which i think were drier than those nearer the glacier which probably still have seepage)..
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Cohan, thought you might be interested in these pics of the rock garden at Tilliepronie House in Aberdeenshire. The rocks are massive and would have needed heavy machinery to move.
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clearly the basis of the landscape here is glacial, though apart from gravel deposits (none on my place, unfortunately) i'm not clear on where the line is between what was dropped off, scoured away, and what was here before the glaciers-the point i forget about most--that there could have been soil here before glaciation which remained after? was it all removed and dumped back?
Bedrock that had been exposed on surface long enough to be broken down into soil would certainly have been the easiest to be bulldozed off by moving ice, so chances are that much of it was removed, but I couldn't guarantee that. On the other hand, in all the wells I've drilled in the areas I've worked, I've never seen any reason to think there was a preserved Cretaceous (for example) soil horizon under the glacial drift - it tends to be a clean surface. So from a limited dataset and with much broad assumption applied, I'd venture that pre-existing soils were largely planed off in this area.
anyway, yes, i was thinking that moraines are closest to what i was thinking of as a finished product :)
would you say that till is what plants are growing in in places such as at the foot of glaciers? those that i saw near columbia icefield were all in more or less soggy soil, i think, not sure if they ever get dried out in mid summer--i was there in july, i rather doubt at that altitude there is much time between melt and new snow, and as you say, what 'soil' there is among the stones is clay, so not much drainage other than on slopes or pockets that are mainly stone (such as the moraines a bit farther back, which i think were drier than those nearer the glacier which probably still have seepage)..
On your last point, yes, I was going to mention something about that but it seemed too complicated and too contrary to accepted rock gardening assumptions to wade into, LOL! Yes, some of those plants are growing in what is essentially till - it's melting out directly from the glacier, and where it is not being winnowed and sorted by running water, it's just till (as opposed to any more sorted and permeable substrate). Yet alpines grow there. I would venture to say that much of what has been written about and accepted as the only truth about growing alpines comes from observations of what may be necessary in very wet and warm(er) climates (i.e. the UK) where perfect drainage and shelter from humidity/rainfall may be necessary. It is not necessarily always so in nature.
The new Wrightman's catalogue describes Halda's method for planting tufa crevice gardens by splitting tufa slabs along bedding surfaces, then buttering one side with a clay paste, inserting bare root alpines then sandwiching on the adjoining slab. I expect this sounds pretty unorthodox from the "perfect drainage" viewpoint. (In this case, however, drainage is still being provided by these slabs being elevated around the level of the surrounding soil in the trough or bed, and by the tufa itself.)
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So from a limited dataset and with much broad assumption applied, I'd venture that pre-existing soils were largely planed off in this area.
On your last point, yes, I was going to mention something about that but it seemed too complicated and too contrary to accepted rock gardening assumptions to wade into, LOL! Yes, some of those plants are growing in what is essentially till - it's melting out directly from the glacier, and where it is not being winnowed and sorted by running water, it's just till (as opposed to any more sorted and permeable substrate). Yet alpines grow there. I would venture to say that much of what has been written about and accepted as the only truth about growing alpines comes from observations of what may be necessary in very wet and warm(er) climates (i.e. the UK) where perfect drainage and shelter from humidity/rainfall may be necessary. It is not necessarily always so in nature.
The new Wrightman's catalogue describes Halda's method for planting tufa crevice gardens by splitting tufa slabs along bedding surfaces, then buttering one side with a clay paste, inserting bare root alpines then sandwiching on the adjoining slab. I expect this sounds pretty unorthodox from the "perfect drainage" viewpoint. (In this case, however, drainage is still being provided by these slabs being elevated around the level of the surrounding soil in the trough or bed, and by the tufa itself.)
i was also, without ever having really thought about it, assuming that everything here was left by glaciers, but once stopping to think about it, i wasnt sure--bedrock seems awfully far away, here, and i assume some of the soil is from plant deposits post glaciation, but hard to imagine that is very deep in this climate, apart from wetlands, where peat/grass/sedge deposits seem much thicker; i only have to dig a foot or so down before the soil seems largely inorganic..
the halda article sounds interesting, i will have to take a look to see if its on the website also..
no doubt those plants growing in that heavy wet soil are a particular group-such as those mentioned in catalogues as growing in 'cold screes' with snowmelt, etc; i was already planning some spots in my rock garden with some sort of plastic lining or containers-i was thinking about the thick black rubber basins used for feeding/watering livestock-beneath the soil a few inches or more, to hold moisture in some areas for plants that seem to grow in those kind of spaces, yet not wet right up to the crowns; i thought some areas like this could also hold extra water after precip and trickle it out to other parts of the garden(i havent fully decided on the details, will partly depend on how it seems to work when i actually try it!)...
i have a plant of Saxifraga aizoides that i collected last year (not by the glacier in the national park, where it was also growing, but lower down outside the park) it was growing with primula and others on the edges of a wet gravelly clay slough/pond; i potted it in local clayey loam with gravel and set the pot in a saucer of water and it did very well, ditto for Primula mistassinica (sp?) from the same location, so my aim is to sort of duplicate that pot in a saucer of water effect for a section of garden..
no doubt many of those plants that need perfect drainage are from much different environments-an exposed rocky outcrop or crevice would be a quite different thing than these dense areas behind glaciers; and as you suggest, a focus on drainage is likely to be much more crucial for places that have large seasonal precipitation at a time certain plants may not want it...
my old rock garden, built when i was a teen, and didnt think much about soil or drainage, did have a lot of rocks, with soil filled in around them, so there would have been good drainage, but the soil itself was just our local clayey 'grey wooded' loam..not that i was growing anything too fancy-- a few natives from the foothills and drylands, and a number of semps..
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Cohan, thought you might be interested in these pics of the rock garden at Tilliepronie House in Aberdeenshire. The rocks are massive and would have needed heavy machinery to move.
thanks for those, roma--it looks like a really wonderful garden! i particularly like the look of age, where each species seems to have spread a bit rather than being one little dot of each thing..
now if only i had a pile of stones like that! (and the requisite moving equipment or swedish moving skill ;)
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Lori:
I agree with your comment about growing conditions in the garden not necessarily replicating nature. I find it fascinating that alpines in the mountains often grow in fine material. In his book 'Alpine Plant Life' Christian Korner notes that " alpine soils often contain - counter to expectations - large fractions of very fine grain sizes". But he also observes that grain size increases with altitude because more recently weathered material is coarser. High alpines stay dry under the snow in winter and then can get soaking wet during snowmelt and spring rains. But I guess the steep slopes compensate for the poor soil drainage and the period of wetness is relatively short compared with our rainy winters on the coast. In the rock garden we use a coarse soil mix, not because it replicates natural soil conditions in alpine areas but to compensate for the different climate conditions to which we are subjecting our plants in the garden. On top of the glacial till, most of our rock garden 'soil' is coarse sand at least half a metre deep and much deeper in some locations.
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Cohan, thought you might be interested in these pics of the rock garden at Tilliepronie House in Aberdeenshire. The rocks are massive and would have needed heavy machinery to move.
this is very elegant execution with irregular igneous rocks. To work with them remains me one saying of Joyce Carruthers: there is many ways how to skin a cat.