An unexpected consequence

At the end of March this year, I wrote about gutting the old rose garden and making the sunken garden more of a feature in a simplified scheme. Reader, as the grass has grown I have been meaning to update with a suitably flattering photo of the new configuration. I have been delighted with how effective it is, despite Mark commenting that he liked the previous borders. He didn’t garden them, I replied tartly.

Sometimes there are unforeseen consequences. And we did not forsee this one. Clearly, the cultivated garden borders that were there before soaked up a lot of water. As soon as we cleared them and levelled the ground, the sunken garden started flooding. It is the lack of vegetation, we thought. When we get heavy rain, it is turning the soil to a smooth surfaced, muddy area that sheds the water immediately rather than absorbing it. When the grass grows, it will be better. But no.

We get heavy rains here, torrential at times. I usually observe that in a climate with relatively high sunshine hours and a relatively high rainfall of 150cm, it means that the rain tends to be heavy and then the skies clear and the sun comes out. We also have excellent drainage; surface water is absorbed within twenty minutes of the rain stopping. But this does not solve the sunken garden problem. The pond is filling with mud, the goldfish are unhappy and the little raised gardens which are in the sunken area are full of treasures that are threatened by the sodden soil.

What to do? For technical reasons (mostly to do with the roots of our enormous rimu trees), we can not recontour the lawn to shed the water in the opposite direction. We debated installing drains but the water still has to go somewhere and it would mean creating a sump nearby. Should we make a low barrier to stop the flow of water over the sides but how would that look and would we then be channelling the excess water down the steps? We are still thinking.

While I really like the look of the top edging being on the same level as the lawn – the status quo – that is not an option. At this stage, we are thinking that creating a whole new top edging sitting just 2.5cm above the level of the lawn will be the solution. I considered doing it in pavers but concrete will give a crisper, cleaner line.  That is a summer job because it will involve boxing up and pouring concrete. It is not an easy option because the top edging has a small lip that gives a better finish rather than keeping it flush with the walls. Our Lloyd, who does all the concreting, can’t quite work out how Felix did it in the first place (the slabs were clearly poured in situ) but he is thinking through how best to redo it 60 years later.

Fresh concrete is very stark and white and sticks out like a sore thumb in an old garden. Fortunately Lloyd is equal to this. He adds some black colouring to the mix to get a more aged grey tone and after it has been poured and levelled, he sprinkles sugar on top of the smooth surface, hosing it off when nearly set. This takes off the fine top layer so what we finish with is exposed aggregate in darker grey shades. He has done it elsewhere here and the new melds very quickly with the old.

It is a lot of attention to detail but this new look garden needs that attention to make it appear a seamless blending of original with new. Or perhaps I should say, we strive to make the new appear old from the start

Vireya rhododendron himantodes is charming, different and a comparatively rare species, not easy to propagate and grow but thriving in the sunken garden. We do not want to lose it to wet feet, as we call sodden root systems.

For reader Pat, who commented on this technique – this is the exposed aggregate look which, when combined with some dye in the concrete, makes new concrete look aged from the start rather than the glaring white of freshly laid concrete.

23 thoughts on “An unexpected consequence

  1. tonytomeo

    Wow, that certainly is a sunken garden.
    One of our vast lawns was installed in what was formerly a shallow pond. It is working out nicely, but only with an elaborate drainage system. I was not here when it was installed. I am glad that it is giving us no problems. I can see what drains out of it, and I would not want to have it back up!

    1. Abbie Jury Post author

      It is what I call the DIY colonial Lutyens look. Mark’s father constructed it in the 1950s and all the sides, base and steps are stone, granite and marble mostly. I am sure it was Mark’s mother who planned it but they would have been working from books because neither had travelled at that stage. In fact I can pretty much pin down which books inspired it, given we inherited their books. But what they didn’t work out from the black and white photos is that the English versions were much shallower. This one is really deep – so deep that we are often asked whether it was once a swimming pool – all dug by hand and horses may have been used but Felix did not own a tractor back then. I like the fact that the simpler layout makes it more of a feature.

      1. tonytomeo

        I happen to like they symmetry too. Nothing is symmetrical here. Landscape ‘designers’ are so disdainful of formality and symmetry. I happen to like Early American architecture and the bisymmetrical landscapes that go with it; but ‘designers’ will do everything they can to make it more informal and ‘casual’. They are just lazy.

      2. Abbie Jury Post author

        It is clearly cultural, or fashion, or something! I would say landscapers here go for symmetry and at its most boring it is unrelieved symmetry with all plants to be conformist as well. The new age of informal, casual (naturalistic?) design has yet to take hold here. Our preference lies in the middle – some symmetry and form softened by informal plantings, the roots of which can be traced fair and square back to Lutyens and Jekyll.

      3. Abbie Jury Post author

        I am not sure how it is possible to be a good garden designer and not understand plants or, worse, have no interest in them. That is a draughtsman (or draughtsperson). A good architect understands all the materials he or she has at hand including the technical requirements. A good garden designer should be the same and one of the key ingredients is the plants. Otherwise they design what we disparagingly refer to as a graph paper garden.

      4. tonytomeo

        Sadly, the horticultural industries, more than any other industries, attracts those who have flunked out at another career, or who just got bored with their career. I wrote about it before, and how one of my clients explained to me that he had been a chiropractor for many years before deciding he disliked it and became a landscape designer . . . just like that. I explained that my career as a horticulturist was not going too well, so perhaps I should become a chiropractor. He did not like that much, and proceeded to explain to me that he had to go to school and on and on, . . . . as if my career was just so unplanned and accidental. I also wrote about how, although I must supply MSDS in both English and Spanish (because some career oriented people do not believe that is important to learn English), but that most of the people using the dangerous chemicals can neither read nor write.. . . in any language. I can not understand why this is so tolerable in our industries. It would not be tolerated anywhere else.

      5. Abbie Jury Post author

        When we had the nursery I used to despair at self-proclaimed “landscapers” who expected to get trade prices even when only buying a single specimen, who would ask for obscure cultivars which aren’t even in the country so we knew they had only looked at an illustration in a book, who would ONLY buy Setsugekka and no other white sasanqua would do and they would happily clean out the entire stock of one top line but never buy anything else and who would patronise us all the way (because ‘landscapers’ were way up their social scale from ‘nurserymen’). Maybe things have improved since then but there were an awful lot of untrained wannabes kicking around the hort world in the 1990s.

      6. Abbie Jury Post author

        How depressing. Fortunately we seem to have moved into a realm where we no longer get patronised by people who know a great deal less than we do.

  2. Geoffrey Marshall

    This is quite a dilemma Abbie but I’m inclined to think that using pavers is the better option for two reasons.
    I like that look you have now where the joins of the slabs are visible – it gives a lovely rhythm to the line and the corner pieces look like they really belong.
    It should be possible to precast your own pavers using Lloyd’s excellent techniques. Not only could you preserve the joint-line rhythm but you could shape the surface of the pavers to suit. Given that overall they must be raised above the lawn level, perhaps a gentle dome shape so that the edge of the paver meets the lawn level rather than having a sudden small drop – or some other shape to suit your own aesthetic.

    1. Abbie Jury Post author

      Thank you for those thoughts, Geoffrey. I hadn’t thought of tapering off the lawn edge – will ponder this. The top needs to be flat because we walk on it, and I want it a little wider but we are restricted by the closest plants so it can only be maybe 12cm wider but that should be enough. It will have to be poured in sections over several days, as the original top is, so it will be in slabs but larger than pavers. I inspected our store of pavers (we have quite a few stacked up from an earlier project) and I feel they are a bit too small for a clean look and too difficult to get an even level at exactly the right height because of the existing wall construction. I think the underlying construction of the vertical walls is so mickey mouse that we will probably have to pour in situ again. I shall consult with Lloyd.

  3. nays

    If it were possible, I personally would dig a sump either side (er, well perhaps personally instruct someone else to dig them) and drain into those, rather than lose the level finish you currently have. I really love the way it just drops off now that the surrounding beds are gone.

    1. Abbie Jury Post author

      Still in the planning stages here. Drainage tiles and a sump are still being discussed but I think 2.5cm above the level of the lawn will not be too intrusive. Sumps aren’t easy here for us with all the tree roots – as we know to our cost from installing a new septic tank.

  4. Maureen Sudlow

    maybe a small, unobtrusive pump might be the answer. Obviously there will probably only be flooding at certain times of the year… We lived on the West Coast so I know what a problem unwanted water can be.

    1. Abbie Jury Post author

      Sadly, Maureen, we can get these torrential downpours all year round! And we need a solution that stops the water from flowing into the area in the first place.

  5. Tim Dutton

    I guess we’re lucky having a sloping garden. We get an average of 1900 mms rain per year and water drains from all over, via paths, pipes and channels to one of three small streams or a large pond, even from the heaviest downpours. I love sunken gardens and was keen to see how your remodelling would turn out, but we wouldn’t be able to attempt one here: what a shame you have to deal with it becoming a temporary pond. I’d think the raised concrete edge was a good way to solve the problem. Almost all our lawns have concrete mowing strips (we use small pavers) and I’ve noticed that over the years the lawn level has slowly got higher and higher, but 2.5 cms would give you a fair few years of respite if the same happened to your lawn.

    1. Abbie Jury Post author

      The unknown issue, Tim, is whether raising the sides will then channel the water down the steps at either end. Raising the stone steps may be a bigger logistical problem because the steps are, I think, cemented into concrete risers.

  6. Tim Dutton

    How about tacking a low wooden ‘frame’ around the whole existing paved area before you embark on anything permanent to see if it actually diverts the water from the sunken garden? It would need quite a lot of scrap timber of course…

  7. Pat Webster

    However you solve the technical problems, I am confident that the result will be worth the effort. I’m fascinated by the idea of sprinkling sugar on almost-set concrete and hosing it off to give that pitted look. I’ll try that here at Glen Villa.

    1. Abbie Jury Post author

      I can’t seem to add a photo to comments so I will add a photo of the exposed aggregate to the end of the post to show you what it looks like. Lloyd is not in today so I just did a quick net search and there is a wealth of information on using sugar or variants like molasses or even milk powder to achieve this effect. While there are commercial products available and some say mix the sugar with water, I think he just sprinkles the granules over it soon after the wet concrete has been smoothed and lets it dry before hosing it.

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