Embrace the slope?

[Tristan_He]

Should we grow more alpines in vertical or steeply sloping situations? In fact, should this be the default position?



My picture shows a plant of Androsace muscoidea 'Breviscapa', planted this spring, from Pottertons Nursery. It's hairy and Himalayan, the sort of thing I'd expect to struggle in our wet Welsh climate, but because I'm incurably optimistic / deluded (delete as appropriate) I decided to give it a go. I planted it this spring (2015) nestled between some tufa blocks facing northwest. It has had no protection from the elements.

This November and December have been record-breaking in rainfall terms. The nearby ECN weather station on the flanks of Snowdon recorded 686mm in November and 1131mm in December http://www.ecn.ac.uk/news/snowdon-december-2015-rainfall-record. There has hardly been a single day without rain. We're not quite as wet as this, but even so I'd be surprised if we have had less than 1.5m in 2 months. The weather has also been warm and very windy. Yet the Androsace looks pretty much ok.

Vertical locations don't just look more natural for many alpines. They also provide better drainage even in heavier soils, like peat, and protection from the rain (the more so if a slight overhang can be arranged). Crucially, they eliminate the risk of water sitting around the crown of the plant.

Many alpines are difficult to grow because they are prone to winter wet and / or rotting off. These are often advised as needing winter protection and good drainage. But I wonder - are we making life difficult by trying to grow them on the flat? Should we try harder to give them the slopes they need, and natural protection from the elements? And are we designing our rockeries and troughs adequately to do this? Even some rockeries at major botanic gardens can be a bit light on the vertical element.

More vertical rock gardens have other advantages in that they create a wider range of hydrological conditions. The top is going to be pretty dry, suiting things like Sempervivums, Draba or Dianthus for example. At the bottom there will be a steady seep of water (or at least moister conditions) that will suit things that like flushes and other wet places - Primulas and gentians.

Obviously there are certain plants that are routinely grown vertically - Ramondas, Lewisias and almost anything in a tufa wall, not to mention the humble Aubretia. But it's not something I have seen emphasised very much in growing advice for alpines generally. What about Meconopsis for example - most wild photos of these seem (especially tricky ones like horridula, delavayi and bella) to be on steeply sloping ground, or even on vertical locations? Likewise many Primulas (including difficult ones like petiolarids) and Lilium.

Any views?

[Tim Ingram]

Certainly embrace the slope if you can Tristan! Two of the best rock gardens I have ever seen, Alan Furness' and Peter Erskine's, are both built on slopes with a field above and with a lot of stone and rock. Not so many gardens have this situation though (or gardeners the energy, skill and determination to capitalise on it), or have natural rock faces (such as Zdenek Zvolanek's masterpiece in the Czech Republic), so the last of these five pictures taken at Robin and Sue White's garden at Blackthorn shows a completely flat planting made by simply laying six inches of pea gravel over the normal garden soil. The real trick seems to be making the best use of the conditions you are faced with and adapting the way you grow alpines to these. Our garden is flat so raised beds, troughs, a sand bed (and if I could ever discover some, tufa) are the ways we try to grow them.

[Tristan_He]

I love the rocky outcrop in the picture from The Art of Gardening Tim. These are reasonably frequent on Anglesey and known locally as boncs.

I suppose what I'm trying to get at is that non-horizontal gardens are often considered a disadvantage, and even in some authoritative books (e.g. Jim Jermyn's Alpine Plants of Europe), many of the rockery designs seem relatively flat.

Adding height also means you can fit more plants into a given space, which for a plantaholic like me is reason enough!

[Carolyn]

Tim,
Very intersting to see the photo of Steadstone, near Dalbeattie, Dumfries & Galloway (the photo from The Art of Gardening). The photo must have been taken a long time ago. Our local group went to visit a couple of years ago in autumn. The trees have matured and the autumn colours are magnificent. In late spring the garden is a blaze of colour too - rhododendrons, bluebells and a huge number of primulas. The garden was built in a former quarry, the house perching on top of a cliff. It is occasionally open to the public and is well worth a visit.

[Tim Ingram]

I must admit, looking at that picture of the rock outcrop in Graham Stuart Thomas' book, I would have not planted those surrounding trees and shrubs but made a large alpine scree at its base - and abseiled down the rock face to plant into it as Dr. Dilys Davies did in her garden in the Lake District! It certainly looks a garden worth a visit - and we have plans of coming to Scotland in the summer.

Yes, I agree Tristan - I would be more than happy with a sloping garden; it would add an element of drama even without a fascination with alpine plant, and terracing can be very effective too. This the idea behind 'sand berms' that some N. American gardeners make which provide different aspects and moisture retention even in relatively small areas and allow a much wider range of plants to be grown.

[Maggi Young]

   " Steadstone, near Dalbeattie, Dumfries & Galloway (the photo from The Art of Gardening) "

 - could it be clarified  which book this is?  There are several under this title  and I cannot seem to find one by Graham Stuart Thomas?

[Tim Ingram]

That's because I made a mistake in the title Maggi! It is 'The Art of Planting' - perhaps a different thing altogether Would make a good title for a television programme don't you think?

[Maggi Young]

Ah! There's often a clue!   


The Art of Planting: Or the Planter's Handbook      Hardcover – 1 May 1984

Hardcover: 288 pages
Publisher: J.M.Dent & Sons Ltd (1 May 1984)
Language: English
ISBN-10: 0460046403
ISBN-13: 978-0460046404

[Leena]

I will continue this thread because my question concerns also a slope. 

By our root cellar I have a place to plant something new, this spot is very different to any other places I have in the garden, and I would very much like to hear what plants should I try in this place.

The challenge is that it is a place where snow melts first when the ground is still frozen. It gets full sunlight only until mid May when the trees grow leaves and after that it is semishade, so it is not good for rock garden plants which require full sun. Another thing is that the slope is made from rocks, and there are two big birch trees (the ones in the back in the picture, the smaller one in the front is going to be felled), so the ground is very dry in the summer (with rocks and birch roots).
I though that I would like to make a spring bed in it. I could try some snowdrops, but what other  bulbs would survive the frozen ground and freezing night temperatures without snow cover, and then very dry summer? What other plants would you suggest I could try?
The right side of the cellar is similar slope with more space to plant something.

[Gabriela]

Leena - a very nice sloped corner!
In exactly the same conditions - very sloped, rocky and exposed (sometimes no snow cover), deciduous shade, it grows here Hepatica americana. I was pleasantly surprised to find that the last cold snap didn't kill their flower buds. Most often is associated with Anemone quinquefolia. You will be most welcome for seeds if you want.

[Leena]

Gabriela, thank you for the suggestions!
I don't have either plant you suggested and would like to try them  . I have H.nobilis which I can try, and here it can grow also in quite dry places. Maybe also Hepatica transsilvanica could take dry shade.

[Gabriela]

Yes Leena, H.transsylvanica in the wild also grows on rocky slopes and it goes very well through dry periods. I now remember that Lathyrus vernus shows up with it sometimes, it's a tough one too.

[astragalus]

Leena, how about trying Primula sibthorpii?  Here it grows and flowers well in limited sun and when the garden gets hot and dry it disappears.  It has the ability to go dormant during the summer and then will reappear in the spring none the worse for wear.  I have had it many years in a garden disliked by most primroses.

[astragalus]

There's also a white and pink form of the Lathyrus vernus that's very pretty.

[Hoy]

Leena - a very nice sloped corner!
In exactly the same conditions - very sloped, rocky and exposed (sometimes no snow cover), deciduous shade, it grows here Hepatica americana. I was pleasantly surprised to find that the last cold snap didn't kill their flower buds. Most often is associated with Anemone quinquefolia. You will be most welcome for seeds if you want.

Recommended! Gabriela's Hepatica seeds have excellent germination! They sprout like cress