why create a Crevice garden?

[Robert Pavlis]

The most common form of crevice garden seems to use vertical slabs of stone. It is clear that such a design will provide very good drainage, and the ratio of stone to soil high. Are there other advantages to this design?

You can increase the ratio of stone, just by adding more larger stone to the soil - it does not need to be vertical slabs. The surface could have more stone than the traditional garden.

So what is the magic of the vertical stone?

[Lesley Cox]

Maybe it's just a matter of drainage. In nature, many alpine plants send their roots done into thin, even hairline cracks in the rock which are frequently on their edges or at least far from horizontal and so offer perfect drainage, often with almost no soil or humus at all, the nutients from the rock itself gradually feeding the plants.

And maybe the vertically placed rocks are easier for people to manage, instead of on their flat surfaces, which takes some artistic ability to achieve a really good result.

[Katherine J]

In nature, many alpine plants send their roots done into thin, even hairline cracks in the rock which are frequently on their edges or at least far from horizontal and so offer perfect drainage, often with almost no soil or humus at all, the nutients from the rock itself gradually feeding the plants.

And maybe the vertically placed rocks are easier for people to manage, instead of on their flat surfaces, which takes some artistic ability to achieve a really good result.

I think this is absolutely right, but crevice garden is also a kind of fashion nowadays, like was scree garden before. Undoubtedly it looks great when planted. I intend to make one this spring. One thing is not clear for me, reading articles about. Do they put compost in the crevices or only grit?
Although I had never been able to bundle into a narrow place a plant bought from a nursery, which has a rather big root system cohered with the moist peat in which was grown.
I would like very much to hear the expert's methods.

[David Shaw]

Kathrine, in no way am I an 'expert' but we built a crevice last year.
You are correct in your first statement that crevice beds are the current fashion and they look just great. The main benefit of crevices is to fiberous rooted plants that, in the mountains, push their roots out over considerable distances along tiny cracks. There is often no soil, as such, in these cracks and the plants take their nutrients from the minerals in the rock and the rain water seeping along the cracks.
In the garden I think it would be a brave gardener who did not put any compost at all into the crevices. We tried to keep the gaps between our rocks as narrow as possible but made sure that there was continuity between the gritty compost in the crevice and the ground beneath so that eventually the roots would get to the soil below.
Nursery plants are often too large for planting into an existing crevice bed. Plants should be chosen small with fiberous roots. The roots should be teased out a bit before planting. It is a mind blowing experience to see the Bainbridges demonstrating the planting of a trough in front of an audience - they will take a fat rooted nursery plant and litterally bash it's roots between two bricks into a thin wafer like form before shoving it into a crack!
Crevices have their place in the garden for showing off 'special' plants. The Czechs go a little too far for my tastes but we built three small island crevice beds in close proximity to each other and I think they look quite good. I can recommend them as a feature in most gardens.

[Luc Gilgemyn]

I'm also thinking of building a crevice bed - only disadvantage - as you need lots and lots of rock, it's very expensive in places where rock is costing a lot of money (like here  )

[Katherine J]

Thank you David, I will try it!

Luc, at first I make it only in a not too big trough, so I need not too much stone 
And if it works...

I think that everybody who made just one and it worked for a couple of years, IS an expert.

[David Nicholson]

I'm also thinking of building a crevice bed - only disadvantage - as you need lots and lots of rock, it's very expensive in places where rock is costing a lot of money (like here  )

A distinct lack of mountains in Belgium doesn't help does it Luc

[Luc Gilgemyn]

I guess you're spot on David ! 

[David Shaw]

Luc
Our 'local stone' is river born boulders in a complete range of sizes, pebbles to 'no way am I trying to lift that!" In places the farmers fields are full of them and, at the time of ploughing, they are hauled out and piled at the edge of the field or used to construct stone walls (dykes). Searching through the stones there are many that are fairly flat on two sides and these are what we use in our garden construction, including the crevices. Do you not have the boulders in Belgium or the fields of a finer structure.

[mark smyth]

How about this natural crevice in a garden here in N Ireland

[Luc Gilgemyn]

Nothing like it David !
All the farmers get out of "Flanders fields" are unexploded shells from WW I 
No rock anywhere near here - so everything has to be payed for...  and will cost anything (according to the kind of rock you want) between 0,15 and 0,35 £ per kilo  Very profitable business for garden centers out here.
The ardennes are the only area where you will find some rock, but you'd need to buy 10 tonnes or so from a quarry...

[Lesley Cox]

The topic is called Why create a Crevice Garden? and Mark's picture of a natural crevice says it all really. In each crack or crevice, small plants have established, drawn by the slightly damper conditions there and the fact thast they can get their roots down INTO the rock where they are fully protected from heat, cold or anything else. A well-made crevice garden looks fantastic, as do the natural kind. So ideally, when we make such a garden, the rock slabs should be as close together as possible and the tops of the plants will spread out over the surface.

As David says, it's important to have continuity between the lowest soil and the mixture in which the plants will grow. A high proportion of sand means that the mix can be drizzled into the crevices and leave no air holes. But yes, do add SOME compost of some find. I'd avoid peat altogether as if it dries, it shrinks and is almost impossible to moisten again, short of soaking it in a bucket.

Where practicable, use seedlings or recently rooted cuttings to insert in slim cracks. Or pull nursery plants apart to make smaller ones, with less root to be squeezed into the space.

[gote]

Crevices are undoubtedly a good way to grow alpines but it is, of course, impossible to take them to the show bench. The crevices do not need to be vertical. I used to grow many things in a retaining wall built from flat stones. I put a little soil between the stones and had, of course soil behind. The stones were arranged in a "staircase way" so the plants did not hang out from the fissures as they otherwise sometimes do. These pictures are forty to fifty years old so the quality could be better.
The closeups are Sempervivum arachnoideum, Thlaspi stylosum. Edraianthus pumilio and Draba aizooides, The last picture shows the same kind of sempervivum planted in a natural fissure in our bedrock The fissure is 5-10mm wide and depth unknown.
This winter is (until now) the warmest since records started in the mid 18th century.
I hope there will be no backlash because everything is starting.
Göte   

[Katherine J]

Thank you Lesley and Göte (also for your pictures)! Yes, I thought I would use rooted cuttings and seedlings.

[Kristl Walek]

I thought you might like to see the crevice garden constructed at the Montreal Botanic Garden a few years ago (2006). I can't find my 2008 pictures (planted and semi-established) of the same garden, however bare bones gardens are a fascinating thing to see.

My own crevice garden (now 10 years old) was not built with vertical slabs (my own aesthetic preference), but with large pieces of limestone pieced together like a jigsaw. I'll try to post some pics of this later.