Contents of the Spring 2012 Northants News

                    Sedums for the Rock Garden                                      Trevor Wray

Many species and selections of Sedum make excellent, long lived plants for the garden. They are generally grown for both their foliage colour and attractive flowers which are a magnet for bees and butterflies. They are best in a sunny situation in a soil which is free draining and not too fertile, but generally they tolerate some shade and everything except a water-logged soil.

The names of plants in garden centres are often confusing and sometimes actually wrong. As a start the genus can be seen as Sedum, Hylotelephium, Telephium and Petrosedum. Then there will be the species and/or a cultivar name. These are often wrong; visiting Cumbrian garden centres I saw three different plants labelled Sedum 'Coca-cola' varying in their vigour and leaf colour and the fairly new selection 'Angelina' seems to vary a fair bit. The alpine species seem to be a case of pot luck at labelling time and sometimes even the picture label doesn't match the plant.  

Within the group there are plants for the flower bed (or the herbaceous border if you have that sort of garden), and the rock garden. Some of the larger rock garden kinds are suitable for the front of a border. A few should not be let loose in the garden under any circumstances because of their vigour and propensity to spread by broken stems, leaves and even seed. My attractive 'Angelina' is confined to a pot but still tries to escape. I despair of ever clearing Sedum album from my peat garden. But don't let me put you off; it doesn't become a less attractive plant because it has the wrong name and most growers lose the labels quickly anyway.  

Sedum in the garden are a magnet for butterflies and bees. 

Of the kinds hardy in the garden some are herbaceous (annual stems dying back to a rootstock) like Hylotelephium and some evergreen. Here is a selection of my favourites.  

Sedum (or Hylotelephium)  ruprechtii

Sedum (or Hylotelephium) 'Autumn Joy': This old favourite, (it is an RHS Award of Garden Merit plant), is an herbaceous cultivar which stands a couple of feet tall and has large flat heads of small red flowers. Butterflies love it! 

’Strawberries and Cream’ (right) is another favourite here. There are many other large growing Hylotelephium types grown for coloured foliage. I like Sedum 'Chocolate', (guess what colour the foliage is), and 'Frosty Morn' with green and yellowish-white foliage. Purists who like to grow species could try Sedum ruprechtii (left) which has white flowers and is another AGM plant.  

Sedum (or Hylotelephium) 'Raspberries and Ice'

Sedum (or Hylotelephium)  ruprechtii

Sedum (or Hylotelephium) 'Raspberries and Ice' 

Sedum (also known as Hylotelephium and Petrosedum) rosea

Sedum roseum: You should grow this because it is a British native, (from the very far north of Scotland). From a nobly rootstock stems with glaucus leaves grow in spring to produce greenish yellow flowers in early summer. A little bit weird, its spreading habit is reminiscent of some Euphorbias. It has the sort of form that should agree with succulent growers. As a Sedum, it has a claim to fame in that it is impossible to grow from stem cuttings or leaves, (the wise men say). However why would you even bother when it is so easy to break a few bits off that knobbly root and pot them up?  

Sedum (also known as Hylotelephium and Petrosedum) roseum 

Sedum 'Coca Cola': As I mentioned there is some variation in the plants you get under this name. Mine has silver grey leaves. However they are herbaceous plants with a spreading habit, (rather than upright as in S. spectabile.), suitable for the front of a border or rock garden. In late summer there are flower heads of pink, which again welcome butterflies. 'Coca Cola' is a hybrid of S. cauticola; you noticed the similarity no doubt? S. cauticola is an alpine plant of much smaller habit but still herbaceous. It has selections or hybrids named 'Lidakense', ‘Betram Anderson’ and ‘Vera Jameson’ which are all worth growing. They can be spectacular grown over a rock

Sedum 'Coca Cola'

Sedum ‘Coca Cola’ tumbles from the wall of a raised bed in my garden.

Sedum ewersi (Hylotelephium ewersii): This is a true alpine with glaucus, green leaves and wiry glossy, brown stems. Purplish-pink flowers are at the tips of the branches in August and September. Branches tumble as far as three feet on mature specimens. It is a hardy, deciduous perennial that is easy to grow.

The following plants are all evergreen, (well not always green, but you know what I mean), and what we would loosely term alpines.  

Sedum spathulifolium: This is mostly grown in the form 'Cape Blanco' which is covered in white farina (powder) in summer. In winter the leaves are purple and look like the equally attractive cultivar 'Purpurea'. This looks especially good with contrasting yellow flowers low against the foliage. There is a green leaved version which is not worth bothering with and a sickly yellow which is tricky to grow outside.

Sedum oregonum: To get the best from this stonecrop it must have a sunny and dry situation. Bright green leaves in spring begin to turn brown, then an unbelievable red in high summer. It has contrasting bright yellow flowers again.  

Sedum oregonense sounds similar but has lime green leaves and cream flowers. Guess where these two come from.  

Two attractive stonecrops - Sedum orogonense with green leaves and Sedum spathulifolium ‘Cape Blanco’ with white in Jeff’s garden.

Sedum dasyphyllum: This is a very variable species in the wild mostly in forms with tiny glaucus leaves in pastel shades. Think pale green, pink, lilac... In summer it can form a delicate mat of great beauty. However a wet winter will decimate it and, as you look at the slimy mess, you wonder why you bothered. Do not despair; a few live leaves is all it needs. They quickly recover. My best plants are often self set in dry sunny places.  

Sedum dasyphyllum

Sedum dasyphyllum with tiny leaves in pastel shades.  

Sedum acre: I hesitate to recommend this aggressive, though diminutive, spreader. This is the swathe of bright yellow that catches your eye in summer along the central reservation of dual carriageways. Not in flower it is grass green the rest of the year and spread by the passage of large vehicles no doubt. Every scrap is a potential plant somewhere and don't even think of trying to hoe it to death in your garden. (Ho, ho!) However, after the warning on the packet, there are some more refined forms. Sedum acre 'Aureum' has pale yellow foliage in the spring when it is most attractive. It looks like its yellowness saps its vigour. By summer it is not so good and it (or at least mine) is sparing with its flowers. S. acre 'Elegans' is similar There is also a miniature form call 'Minuta' as you would expect. I haven't let my 'Minuta' out of its pot just in case.

Sedum acre ‘Aureum’ contrasts with a black stone wall in the Lake District.

Sedum pachyclados

Sedum pachyclados: This is a fairly new introduction that is now mass produced for garden centres. With its mat of light blue-green, almost silver, rosettes it is attractive but it is a fairly active spreader, (by suckers, not the regular broken stems and leaves). The ideal situation is jammed between rocks with any attempts to escape being curbed. A few years ago I planted it in a trough and it is skirmishing along a border with some vigorous silver saxifrages. I think the Sedum might win. My first plant was overtaken by a spreading conifer which was an unfair fight. I see on the internet that it has white flowers but I do not recall seeing them on my plants.

I hope I have whetted your appetite for these plants. They are definitely ‘succulents’ and they definitely have a place in your gardens. Since they are so easy to propagate, if you want any of the above, just speak to me at a meeting.


Sedum pachyclados lined up for sale at the Garden Centre.

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