for the perennial garden
Gorgeous, fleshy, colourful succulents: the large garden sedums are indispensable, trouble-free late-flowering perennials, loved by pollinators. Here I share the best performers from my garden.
Garden-worthy sedums come from an extensive group of drought-tolerant succulents which are part of the stonecrop (crassula) family.
Many of the true sedums are tiny alpine plants, primarily suited to growing in alpine troughs, gravel beds or on sedum roofs.
In this article, however, I am looking at the larger, herbaceous sedums that can hold their own in the perennial border.
Confusingly, most of these herbaceous sedums have recently been moved from the genus Sedum to Hylotelephium, but for simplicity, I will refer to them as Sedums throughout this article. Most nurseries now use Hylotelephium on their labels.
Border sedums are versatile deciduous perennials, which come in two main size categories: the larger, upright varieties reach 1.5 – 2ft (45-60cm) tall and have thick stems, while the smaller, trailing varieties tend to spread outwards more, while only reaching 6 – 12in (15-30cm) high.
Origins of Garden Sedums
Origins of Garden Sedums
Most of the large garden sedums are hybrids and variants of these two wild species.
Native to the UK is Orpine (Sedum telephium) — pictured here — which has fleshy toothed leaves alternating along the stems, and tall flower-heads, often described as broccoli-like.
The other wild species is the Ice plant (Sedum spectabile) — native to China and Korea — which has leaves in opposite pairs, and larger, flatter heads of pink flowers.
Both species show considerable variation in size, leaf and flower colour, in the wild, which has been further elaborated through hybridisation and cultivation, leading to the availability of many named cultivars.
This provides the gardener with many options including a variety of flower colours in shades of pink, red, yellow, green and white. The stems and foliage of sedums come in many succulent colours too: purple, reddish-yellow-green and glaucous blue-greens as well as variegated forms.
LARGE / UPRIGHT
40-90 cm | 16-36 in
Sedum spectabile ‘Brilliant’
Sedum spectabile ‘Hot Stuff’
S. telephium ‘Purple Emperor’
(purple/pink 60×100 cm)
SMALL / TRAILING
15-40 cm | 6-16 in
Sedum ‘Vera Jameson’
S. SunSparkler Series
S. ‘Ruby glow’
(dark purple/pink; 30x80cm)
Sedum sieboldii Variegatum
MAT / GROUND COVER
5-15 cm | 2-6 in
(glaucous/pink; 15cm x 75cm)
S. ‘Bertram Anderson’
S. spurium cultivars
In this Article…
Large Upright Border Sedums
Flower and foliage colour
Border sedums come in every possible shade of pink: from reddish to purplish, with brighter candy-pinks in the middle. However, green, white and pale-yellow flowered varieties exist. The succulent leaf and stem colour is a big part of the appeal, coming in greens, blues, purples and bronzes. Subtle variations in leaf shape, texture and growth patterns add to the diversity of cultivars.
Sedums grow from a dense crown of tightly packed buds, typically producing a shuttle-cock shaped clump of stems topped with wide flower heads. Generally, they form 2ft x 2ft (60x60cm) clumps, however, larger varieties can reach 3ft x 4ft. In my experience site, soil and light can affect final size which makes planning a bit tricky.
Season of interest
Spring: buds emerge from a dense crown, creating an interesting textured dome of coloured succulent foliage.
Summer: expanding clumps of colourful succulent stems, topped with intricately branched flower heads — fascinating even before the flowers open.
Late Summer: flowers open and immediately become a magnet for pollinators. Flowers typically fade to brown; some more gracefully than others.
Autumn: The foliage and stems of some varieties take on interesting autumnal hues before turning brown.
Winter, their dried stems and seed heads an be quite sculptural and have been used effectively in winter garden alongside silver birches and red-stemmed dogwoods.
The Chelsea Chop
Most sedums need no staking, but the largest, top-heavy varieties (such as S. spectabile ‘Brilliant’) can flop as the clumps get bigger. Fortunately, they respond to the ‘Chelsea Chop’ — cutting back all the stems by 3-6 inches in May. Following this the stems produce side shoots, carrying several slightly smaller flower-heads. The overall growth is reduced, so stems are less likely to flop.
An alternative to the Chelsea chop, is to grow the largest sedums through the wire frame of a large upturned hanging basket.
Three classic Large sedums
Sedum spectabile ‘Brilliant’
Beautiful at every stage with glaucous-green leaves and large flat heads of bright pink flowers in September. Grows into a large clump. Stems can flop, so are best given the Chelsea chop in late May, or grow it through an upturned hanging basket for support.
More upright and with sturdy rhubarb-coloured stems, which rarely need staking. The foliage is a dark reddish-green. In summer the broccoli-shaped flower heads carry broad heads of pale pink starry flowers loved by bees.
Sedum ‘Autumn Joy’
Similar to ‘Brilliant’ but with darker pink flowers turning to brick-red, and with darker green foliage. Flowers from late August into October. Unfortunately, its flowers are sterile, so it does not appeal to pollinators. (The leaves in the photo above are nearby Agapanthus)
Large Upright Border Sedums
▲ Sedum ‘Strawberries and Cream’ is one of the more compact large sedums which over time grows into a clump 50cm wide and tall. In May and June, the foliage and stems take on an unusual bronze-red colour. The flowers open a beautiful mix of yellow and pink in late July.
Unfortunately, the blossoms are over in just a few short weeks, but during that time Bees will visit incessantly. The biggest downside is how quickly the flower-heads turn brown – a sight we expect only later in the summer. If you find them unsightly, just dead-head, but if you can put up with them until the autumn they will become an asset.
▼ I grow Strawberries and Cream in a raised bed with other drought tolerant plants which provide a long season of interest. Below: white flowers of garlic chives (Allium tuberosum), the blue fairy thimble bell flower (Campanula cochlearifolia ‘Elizabeth Oliver’) and mauve Society garlic (Tulbaghia violacea), pink hyssop (Hyssopus officinalis ‘Pink form’) and late-flowering pink German garlic (Allium senescens glaucum)
Small Trailing Border Sedums
Many of the small border sedums change colour throughout the season. Above is Sedum ‘Vera Jameson’ early in April. The foliage is distinctly glaucous blue, with a hint of dusky purple in the stems. By July, however, the same plant has spread to over 3ft (90cm) across with the stems and flower heads taking on a strong Burgundy red. (Seen here growing charmingly with white gypsophila and the diminutive pale-blue Campanula ‘Elizabeth Oliver’)
Sedum ‘Plum Dazzled’
A wonderful small sedum, with deep purple foliage all season. The flowers open in August and September – a good deep pink. Growing here with glaucous-blue myrtle spurge (Euphorbia myrsinites)— h20cm s40cm.
Mat-Forming, Alpine Sedums
One of the most reliable ground cover sedums is the crimson stonecrop (Sedum spurium). This low growing, mat-forming alpine is tough enough to form a carpeting plant at the front of the border or in a gravel or rock garden and even tolerates some shade.
There are many named cultivars of crimson stonecrop, including white, pink, red and yellow-flowered forms. The foliage consists of small serrated succulent leaves in whorls along trailing stems. Most cultivars have dark green leaves, but red, purple, variegated and golden leaved forms can be found.
▲ Sedum spurium ‘Spot on rose’ has incredible pink cactus-like blooms. The one above is growing happily in the shade of a small deciduous shrub (Vitex agnus-castus)
Sedums are easy to grow being generally trouble-free and long lived. They prefer a failrly free-draining and not-too-fertile soil in full or part-sun. Avoid excessively rich or waterlogged soils.
Sedums grow from a crown of densely packed buds. As the stems grow they spread outwards, forming a shuttlecock shape. Many of the smaller varieties have long thin stems, which trail across the ground, leaving the centre of the plant open with flowers around the edge. These wandering stems can snake effectively through adjacent plants.
The taller varieties do well in the middle of the border, planted singly or in groups of three or more. The smaller varieties need to be placed to the front of the border where they look good against gravel, rocks or low ground-cover plants. Some of the lower-growing varieties will trail over the edge of low walls or raised beds.
Sedums often self-seed with the offspring showing a high degree of variation. I like potting these up and seeing how they develop: often, unfortunately, their flower colour tends to be less distinct than the parent.
Sedums are relatively easy to propagate.
(1) Division: Clumps can easily be dug up, divided with a sharp spade, and replanted.
(2) Offsets: Sedum stems readily produce roots and shoots close to the soil. If you spot a stem that is sprouting buds close to the soil, simply cut back the main stem somewhat, then remove the remaining section with the basal buds using a trowel to retain any soil the stem has rooted into. Pot it up using a free draining soil.
(3) Cuttings: simply cut a stem in summer, remove the lower leaves and place it in a jar of water, until roots sprout. Pot the cuttings up and grow on.
Slugs and Snails
Although usually pest free, watch out for slugs and snails attacking the crowns in winter and early spring. Keeping the winter crown free of leaves and mulch can help.
One problem with some of the named varieties is reversion, where a desired trait such as variegation, decorative leaf or flower colour spontaneously reverts to the typical form. This can affect part or all of a plant, and is especially problematic when plants are propagated. Consequently, named varieties can vary considerably between nurseries, making accurate identification difficult. If you want more of a particular variety, it is often best to divide your own plants rather than buy new ones, which may look quite different.
If your soil or pots are too moist, the roots of sedums will rot. Often, the plant will soldier on, and appear to be alive, even producing new buds and shoots from the base in spring. Give the old stems a slight tug, though, and it will come away in your hand. If the soil dries out, new roots will grow, but the plant will suffer a set back and take a few years to recover.
Sometimes vine weevil grubs attack the roots of sedums grown in pots. The symptoms are similar to root rot, with the plant gradually deteriorating, and eventually coming away from the soil. For chemical control try Bug Clear Ultra Vine Weevil Killer. Alternatively use a biological control such as Nemasys® Vine Weevil Killer.
Growing Sedums in Pots
- Sedum spectabile — as part of a group of pots with Agapanthus and white roses
- Random seedling — found and potted up. Grown on in greenhouse with other succulents.
- Sedum ‘Matrona’ — growing happily in terracotta pot.
- Sedum ‘Double Martini’ — planted with other succulents in terracotta planter.
- Sedum ‘Strawberries and Cream’ — rescued self-sown seedling
- S. spectabile cuttings — cut stems rooted in water then transplanted into pots.
△ COMBINING SEDUMS WITH SILVER FOLIAGE This unidentified pink sedum is one of my favourites, growing into a neat dome just 40cm high. It has rounded grey-green leaves and soft pink buds. I have combined it here with silver foliage including the fluffy mugwort Artemisia schmidtiana ‘nana’ and the fine pointed foliage of Snow in Summer, Cerastium tomentosum.
▽ SEDUMS IN A COASTAL PLANTING Sedum spectabile ‘Brilliant’ is planted here with other perennials that tolerate coastal conditions: salt-laden winds and full sun. Top left is the lilac daisy Erigeron glauca ‘Sea breeze’, while in front is the hardy ice plant, Delosperma cooperi. Agapanthus, Echinops and Eryngium would also be work as companions.
△ DROUGHT-TOLERANT PERENNIALS In this part of my garden, the purple foliage of Sedum ‘Plum Dazzled’ works perfectly with other dry-garden perennials, including Alliums, blue and white Triteleia ‘Rudy’ (bottom left), vivid blue Salvia ‘May Night’ (top left), and the glaucous-blue foliage of Perovskia ‘Little Spire’ (top right) and Euphorbia myrsinites (bottom).
△▽ SEDUMS IN A GRAVEL GARDEN Sedums of all sizes are at home in gravel and rock gardens.
Above, Sedum ‘Plum dazzled’ is growing with (clockwise): Allium senescens subsp. glaucum, Helianthemum ‘Wisley pink’ and Salvia ‘Snow Hill’.
▽ SEDUM ROOF The small alpine sedums will cope well with the harsh conditions on a green roof, growing in minimal substrate with little water. This photo is from my green roof garden a few years ago. In the foreground, red leaved Sedum spurium ‘Dragon’s blood’ and silver-blue Sedum reflexum fight it out. The orange plant in the distance, is Sedum ‘Angelina’ poking up through a carpet of wooly thyme. The plant in the middle of the photo, covered in strange seeds, is Euphorbia myrsinites.