Just finished my first rock garden (minus the plants!)

Hi all,
I live on a limestone hilltop in central-western France. Have been wanting to have a rock garden for many years and have finally managed to have the time and energy to make one.
I studied a lot of book and online advice, including Todd Boland's very useful article on the subject.
So here is the story so far... Doubtless I have made a lot of mistakes... and feel free to tell me about them.
Being 'hilltop' my garden while moderately large (~1600 sq yds) is fairly flat. The only slope potential is really adjacent to the courtyard where there is a small stone wall about 18" high holding back the 'higher' part of the garden from the courtyard.
So I dug out about four feet of the elevated section storing the topsoil and the large number of limestone rocks which had comprised the wall. (See picture)... (continued next post)

... This took me some time (a few weeks) as I became somewhat depressed at how slow the going was... My big DIY job over the summer was to replace the roof of a small outbuilding (can be seen in the background of the other pictures - not this one, that's the neighbour's house). That yielded large numbers of broken tiles, so I decided to economise on soil and rocks, by starting the inner part of the rockery with this rubble. So I filled the inner part with a triangular sectioned pile of the rubble about one foot high and three feet wide. Originally my intention was to make the whole structure 35ft long, but I ran out of energy after 20ft... but it is still quite sizable.
Here is the pic of the project the first evening when I had just started with the rubble..

This message was edited Nov 24, 2011 3:27 PM

The next day I was able to put the rest of the rubble in and admire my handiwork. I thought about the advice from Todd about holes where nasties such as slugs and ants could make their homes.
Doubtless the best way would have been to fill in all of the holes between the tiles (they are all curved tiles in this part of France) with soil or something, but I couldn't figure how to do that, so I liberally sprinkled slug pellets and ant-killer all over the rubble in the hope that any slug snail or ant who happened along would commit accidental suicide before damaging my plants.
This pic is of the rubble in place.

Next came the first layer of soil. I had to buy a load of grit - very nice river-washed 3-8mm grit. This, for the 'inner soil' I mixed 4:5 with the soil that I had excavated from the wall. I decided to make it a gentle slope on which I would put the largest of the 'decorative' rocks - i e the limestone rocks excavated, but with lichens and markings or interestingly shaped. This turned out to be a bit of a mistake. This was because I later realised that a) the chalky topsoil was very inclined to impact, even with a lot of grit added, and b) that the 'gentle slope' looked unnatural. What I needed was something more like a quadrant of a circle in section steep at the front and curving to flatter at the top.

At the front of the rockery, I now added a number of mainly very large limestone rocks with lichens and moss and other interesting features. I had used a random number generator to choose the position of the different sizes of rocks at the different levels of the rockery - front, middle back - with the proviso that there would be more large ones at the front, more medium ones in the middle layer and more smaller ones at the back. 'Front', middle' and 'back' were each about two feet in width.
Next came the heavy hoofing... adding oceans of limestone rocks... the boring ones.

It was at this stage that I realised the problem with the slope. So I spent a good deal of energy in re-arrangement of rocks and adding more rocks to the front. Then I positioned the remaining 'interesting' rocks on this pile in places where they would protrude when the second layer of soil was added.

I was then all set for the final layers of soil.
Having made the mistake with the first layer, I was determined to improve things. The 'top layer', I had always intended would have a load of home-made compost. I thought that soil: compost: grit proportions would be about 4:2:4, but that I radically changed, with the addition of sand. The final proportions I decided on were 4:4:3:8 in compost:soil:sand:grit. Would have liked more compost, but that was in short supply. Also I was mindful of some articles that I had read indicating that alpine plants often don't need rich soil.
This was deposited on the largely stone structure and a brush and hose used to transport the soil mix down to the lower levels. A final layer was added to fill in the gaps created.
The result is as in the picture.
I fully expect to need to replace some of the soil for plants with individual requirements - lime-haters, for example - but I hope that the structure is about right. With nearly three tons of rock, I certainly don't want to be re-making it in the near future!!!

Hi cinemike! Bravo! You have made a terrific scree garden. It looks as if drainage will be perfect, with all that rock and tile underlay. Looking at your pics, I don't see any kind of weed barrier between the lawn and the flowerbed - and if you have grasses or lawn weeds with creeping roots, they could become a problem. You might need to dig out a strip of lawn behind the bed and either lay wide flagstones or insert a deep vertical edging to prevent weed invasion.

Great... thanks. THat would certaily be a problem. Will do that asap.

Hi, cinemike. I watched your series of pictures with interest. I've wanted to do the same, but lack of enough sun, or more likely lack of energy has held me back. I think it looks great. Now with winter upon us, you can do the fun part - looking through catalogues picking out your plants! Thanks for posting your project on line. It was really interesting. Be sure to post pix of it all planted out.

Since so many folks here have moved over to the NARGS website, I haven't been visiting. So I missed this new rock garden.

Could you catch us up on what you did last year? I bet you got some plants in it?
Tam

Thanks for your interest. I did actually post my story on the NARGS site - but it's really very small beer for serious alpine addicts!.
As I only grow plants from seed, the development is slow. I have planted out some Aethionemas, Primulas, Gentianas, Pulsatillas (my favourite), Veltheimias, Petrocoptis, Edraianthus, Townsendias, Dianthuses and a few that I can't remember at present. The only one in flower at present is Linaria aeruginea.
I have loads (~60) of Penstemons from a packet of mixed seeds that I grew quite successfully last winter and I have planted out in a special border while I wait to see which ones they are - how big etc - before deciding whether to put them in a border of the rock/scree garden. Then there are 18 different species of Penstemon that I am growing from seed this winter following last year's Nargs Seedex...
Additionally I have a lot of Aquilegias from a mixed seeds from the UK national collection bought from Chilterns Seeds last year. They are also planted out in a special border ans I will put some of those in the rock garden when I see what size they are.
Then there are several species of Drabas and Saxifragas that I am gkeeping in thier pots untill they are big enough to plant out.
So far it is maybe 1/3 to ½ full of plants.

Those are the upsides... the downside is that this autumn, I had an explosion of weed seedlings that seemed to overtake my ability to remove them, and with no mature plants with which to compete, they had a field day. I do hoe and pull from time to time, but it is going to be a case of doing that when I plant out early next spring, I suspect. Also, I have the foolish habit of forgetting to label where I have planted young plants (not all the time, but occasionally), so I have been wary of too much hoeing while the plants are dormant in case I slice up a treasured something or other.

Additionally, following a suggestion from someone on the NARGS site, I tried to guard against the intrusion of rhizomatus weeds and grasses from the area of rough grass at the top of the rock garden. In the end, I dug a border there so now the rock garden aims to look like a natural rocky extension of the border above. I have also extended it a couple of metres sideways to encompas an Iris bed... currently mainly coarse local wild Irises which I have had for several years, but with the addition of Irises milesii, douglasiana, sibirica, setosa, lactaea, and some others that I cannot remember at present - all grown from NARGS seed.

Will post some pics when next year's spring growth starts to make it look less like a weedy expanse of gravel!

I am interested in how your garden is doing. Do you have any pics?

Will do....

Ok, this is the overview. I know it's not too impressive but my way of gardening is to grow almost everything fromseed. So it takes some time :0)

At the base level where the rockery merges into the forecourt, I have put/am putting a series of easy to grow plants that overproduced as seedlings... Here Penstemon hirsutus var pygmaeus. They were sown winter 2012/3.