Crevice Gardening ......in defence of rock.....

[Bob Resch]

Andy, like you I am starting out new to crevice gardening. As Maggie indicated Zedenik generously mentored me as I developed my garden structure. The process was valueable and Zedenik's guidance aided greatly. He is generous with his passion. I am going to piggy back on your note with a question of my own. My bed is filled exclusively with coarse sand. Only a few plants are inas our temperatures in Illinois have heated rapidly. I anticipate the sand to be cooler than air temperatures below the surface. This has not proven to be the case as temperatures 20 cm down are running 32 degrees C about the same as the air. This surprises and concerns me. I am interested in hearing from others of their experiences wonder if these sub-surface temperatures will be detrimental long run. Any and all advice welcomed
EdgewoodBob

[Lesley Cox]

I'm very surprised too Bob, at that high a temperature at 20cms depth. Plant roots could just about cook. I understand that growth of temperate plants stops at 24-26 degC. (Stand to be corrected, of course). While not in a crevice garden, my experience generally is that plants survive hot periods better when their roots are well moistened, rather than dry. In other words, things will survive boiling better than baking or roasting!

[astragalus]

Maybe you're right, Lesley.  I've been using a very coarse sand for years and now am using it in the crevice gardens.  I've always found it to be a wonderful growing medium for plants that don't do well elsewhere in the garden.  Also, the stone that makes up the greater part of the crevice gardens seems to help retain the moisture and the plants there are the last to show signs of distress in this horrible summer of heat, drought and humidity that we have been enduring here.

[Paul Cumbleton]

Could anyone tell me the size of the crevice garden at Pershore (length x width) ? I've asked Pershore themselves obviously but I just thought someone here may know the answer off the top of their heads. It would save someone at Pershore going out to measure it!

Thanks

Paul

[Maggi Young]

Hello Paul,
I've checked the article by Ron Beeston on his work the making of the Crevice garden at Pershore with ZZ and a gang of helpers  in "the Alpine Gardener" number 301  Volume 73 number 3 of September 2005 but the dimensions are not given there. Ian is just chatting on the phone with Ron who says h is best estimate of the size ias around 25 feet by 40 feet .... hope  this helps!

[Paul Cumbleton]

Thanks Maggi, very helpful  and for reminding me of the reference for the article.

The reason for asking is that I have made a proposal to my mangers that the centre-piece of our celebrations at Wisley next year for the centenary of the rock garden should be to build a new feature so that in doing so we also leave something for the future. I would like this to be a crevice garden. I have been asked to provide an idea of cost before any decision can be made as to whether this is something that could be funded. So I am trying to work out the possible cost per square metre. To do this I need to know how much rock it takes to build a square metre of crevice garden. I was told that the one at Pershore used 10 tonnes of rock (can anyone verify this?) but what I don't know is the area that this created. hence the request for dimensions.

If this project goes ahead  I may be looking for advice, never having built a crevice garden before! However, ZZs book is a great place to start and the other contributions to this forum also provide some insight.

Thanks again

Paul

[Maggi Young]

Yes, 10 tonnes is the amount mentioned in Ron's Article.

[ranunculus]

If this project goes ahead  I may be looking for advice, never having built a crevice garden before! However, ZZs book is a great place to start and the other contributions to this forum also provide some insight.

You could do a lot worse Paul than consult dear Anne Spiegel (Astragalus) who has constructed an incredible cliff/boulder/crevice garden in New York State which is one of the finest private alpine gardens that I have visited.

Edit by Maggi: See this thread http://www.srgc.org.uk/smf/index.php?topic=7206.0 where  there is more of anne and Joe's garden

[Paul Cumbleton]

Thanks everyone for their input, I really appreciate it. I have meanwhile become rather confused about sizes! For example, in ZZs book where he mentions the crevice garden at Montreal Botanic Garden, the caption under the picture on page 16 says this large crevice garden is 1.25 hectares (which is 12,500 square meters).Yet in the online article in the International Rock Gardener No. 4 (April 2010) it says this garden is just 150 square meters and used 60 tonnes of rock.. Or was this just for the part of the garden that was reconstructed? – it is not obvious.

Ron’s estimate of 25 by 40 feet for Pershore translates to about 92 square meters. Pershore say that they think the plan on page 10 of ZZs book is of the Pershore Garden (though it does not claim to be). But if so, that would work out about 50 square meters, barely more than half Ron’s estimate. I guess the only way to be sure is to do the 2 hour drive up to Pershore and measure it for myself!

If anyone out there who has built a crevice garden can give me a reliable figure for what weight of rock it took to build each square meter I would be very grateful. It would also be very useful to know what volume of compost it takes to fill the crevices per square meter. (I realise this will depend on the elevation, but if anyone has figures for their own constructions it would be most helpful.) If I can’t provide my managers with some possible costings that are at least roughly correct they won’t even consider my proposal to build a crevice garden at Wisley.

Paul

[Maggi Young]

I take it you have not yet had a response from Pershore, then, Paul?

[Diane Clement]

Ron’s estimate of 25 by 40 feet for Pershore translates to about 92 square meters. Pershore say that they think the plan on page 10 of ZZs book is of the Pershore Garden (though it does not claim to be). But if so, that would work out about 50 square meters, barely more than half Ron’s estimate. I guess the only way to be sure is to do the 2 hour drive up to Pershore and measure it for myself!  Paul 

Paul, it might be a good idea to contact ZZ himself as he managed the building of the rock garden at Pershore and therefore would know the figures (he's not been on the forum for a while, so maybe travelling somewhere).  Another person who was involved with the project at Pershore was Alan Furness who has also built his own crevice garden so I am sure could give you some useful info. 

[Maggi Young]

I'll contact Paul with some info  to help, Diane.

[Jiri Papousek]

Thanks everyone for their input, I really appreciate it. I have meanwhile become rather confused about sizes! For example, in ZZs book where he mentions the crevice garden at Montreal Botanic Garden, the caption under the picture on page 16 says this large crevice garden is 1.25 hectares (which is 12,500 square meters).Yet in the online article in the International Rock Gardener No. 4 (April 2010) it says this garden is just 150 square meters and used 60 tonnes of rock.. Or was this just for the part of the garden that was reconstructed? – it is not obvious.

Ron’s estimate of 25 by 40 feet for Pershore translates to about 92 square meters. Pershore say that they think the plan on page 10 of ZZs book is of the Pershore Garden (though it does not claim to be). But if so, that would work out about 50 square meters, barely more than half Ron’s estimate. I guess the only way to be sure is to do the 2 hour drive up to Pershore and measure it for myself!

If anyone out there who has built a crevice garden can give me a reliable figure for what weight of rock it took to build each square meter I would be very grateful. It would also be very useful to know what volume of compost it takes to fill the crevices per square meter. (I realise this will depend on the elevation, but if anyone has figures for their own constructions it would be most helpful.) If I can’t provide my managers with some possible costings that are at least roughly correct they won’t even consider my proposal to build a crevice garden at Wisley.

Paul

Dear Paul, I am really pleased to hear about idea of  crevice garden in Wisley. I have tried today to find out my stone consumption per square meter. One picture shows 1 m2 bordered with rope. Sorry I didn't take stones from crevices to have exact measurement, but I estimate it around 250 - 400 kg per m2. It fits to figures from Montreal (60 tons for 150 m2), 12 500 m2 is for sure the whole garden. Cunsumption is including smaller stones needed inside crevices, it is important not to underestimate it, as you need a lot of them.It is not enough to use just gravel, I hope that picture shows this little bit. As mediums I can highly recommend clean river sand. It supports so important roots development and as sterile material it also enables plants to establish after planting. Plus it is also very cheap material. In case of rain, you can also cover soil with sand and you can walk withou mud on you shoes. It also enables you to plant crevices even in case of rain, in case of time pressure. There is no problem with nutrition, as plant will root down through sand and quickly reach soil below crevice construction. I add some soil only for daphnes and dwarf conifers. Regarding roots temperature, this year we had around Prague 36 C degrees without any bigger problems for established plants. My experince is that wet sand in crevices is much cooler than air. It is because of no air circulation inside crevices, plus evaporating water cooles sand. Sand is able to abosrb huge amount of water and water has four times higher heat capacity then air. I can also mention watering savings, as there is much lower need to water, as crevices keep water inside for very long time and there is minimal space for evaporating.

[Paul Cumbleton]

Hi Jiri,
Thanks for taking the trouble to estimate your rock usage and for your other helpful suggestions. Today I actually visited Pershore to see and measure the crevice garden for myself. The total area (minus paths) is actually 28 square meters. As they used 10 tonnes of rock, this works out atabout  0.34 tonnes (340Kg) of rock per square meter. This fits in with your estimate Jiri and also with the Montreal example, which worked out at about 0.4 tonnes per square meter.

I still do not know if senior managers at Wisley will go ahead with my idea. Some of the things they have said recently make me think they are backing away from the idea a bit. I hope not. I hope to have a clear answer from them within a week or so.

Paul

[cohan]

Dear Paul, I am really pleased to hear about idea of  crevice garden in Wisley. I have tried today to find out my stone consumption per square meter. One picture shows 1 m2 bordered with rope. Sorry I didn't take stones from crevices to have exact measurement, but I estimate it around 250 - 400 kg per m2.

it looks like there is a lot of progress in your garden since we last saw!