My must-have Sedum

No matter what else happens in my garden there is one plant that I couldn’t be without: Sedum spectabile, or as I should now call it Hylotelephium spectabile. (Botanists at the RHS have changed the scientific name of this class of hardy herbaceous perennials, but I suspect most gardeners will continue to refer to them as Sedums for some time to come.)

Hylotelephium spectabile - A border Sedum to you and me

Hylotelephium spectabile – a Sedum to you and me

The ‘Sedums’ (also known as stonecrops or ice plants) are an easy-to-grow, low maintenance group of succulents that provide year-round interest in borders.

All-year interest

In Spring, the first shoots form a thick clump of fleshy blue-grey leaves. These grow into a large discrete clump through Summer, eventually producing thick erect stems, which are fairly self-supporting, up to 50 cm tall, bearing flat clusters of green buds.

Pile the mulch around your herbaceous plants, up to 2 inches think and up to the bases

In Spring, new growth appears as shallowly scalloped whorls of fleshy blue-grey leaves

Sedum spectabile is at its most spectacular in Autumn, when the buds gradually open to reveal large flat clusters of tiny pink flowers that deepen to a radiant magenta as the season progresses.

Sedum spectabile is at its most spectacular August to October

Sedum spectabile is at its most spectacular August to October

In Winter, the flower heads gradually turn russet-brown. Left standing, these large stately heads add interesting structure to otherwise bare borders, provide protection for hibernating insects and look magnificent on frosty mornings, topped with a sparkling sugar coating.

Frost-capped sedum

Frost-capped sedum

Simply cut down the stems at the end of winter and start the cycle all over again.

I love this plant because …

  • It is ideal in borders, providing interest throughout the year
  • It is hardy to -20 degrees
  • It is drought tolerant (particularly useful this year!)
  • It is easy to propagate (see below)
  • Bees and butterflies love it!!

Sedum care

Sedums do best in light, free-draining soils, but thrive even in my heavy clay borders, although I admit I do add plenty of organic matter whenever I can to improve the soil.

They like full sun, and when fully established they rarely require watering.

If your stems get a bit floppy (this can happen if the soil is too rich) then cut them back by half in May. This will encourage stronger, shorter, self-supporting stems, although they will flower a little later than usual.

Best of all, once you have bought one plant you will never need to buy another, as they are extremely easy to propagate. Simply cut off a short non-flowering stem, in Spring, make a hole in the ground and pop it in. Water and leave it to do its  thing. Alternatively, wait until you have a decent-sized clump and lift and divide as you would any other herbaceous perennial.

I started with one plant and now have them repeating around the garden. No Matter what else I plant, they pull it all together … and never let me down.

I repeat my Sedums at intervals around the garden

I repeat my Sedums at intervals around the garden

Most of all, I love how the bees and butterflies forage over them in Autumn. They are a magnet to insects at this time of year when other sources of nectar are scarce.

I now have a rule for any new plants in the garden. They have to be bee friendly! So no limit on the number of Sedums.

Sedums are extremely bee friendly

Sedums are extremely bee friendly

Different types

There are many different species of Sedum (Hylotelephium), with different coloured leaves and flowers, including variegated, purple-leaved and white-flowered varieties. But Sedum spectabile remains my favourite.

What’s yours?!

Deadheading dahlias

It may be feeling distinctly autumnal right now, but if you’ve planted dahlias the good news is they will keep on flowering right through to the first frosts.

Dahlia bloom

Dahlias will flower from mid-summer to first frost, bringing welcome colour to the garden

There’s just one catch: to prolong flowering you will need to keep deadheading them, thereby encouraging the plant to produce new buds.

The only problem is it’s not always easy to distinguish a spent dahlia head from a new dahlia bud. And you don’t want to be snipping new buds off!

Spent dahlia head or new bud?

Spent dahlia head or new bud?

Identifying spent dahlia heads

If you spot an ageing flower early when there are still a few wilted petals visible, then there’s no problem. Snip it off. The difficulty arises when the old dahlia flower has lost all of its petals. The hard bulbous part at the base of the flower (the calyx) then closes over to form what looks remarkably like a bud.

However, you can tell the difference between a spent dahlia head and a new dahlia bud by the shape. A spent dahlia head is slightly conical, almost pointed (as in the example above), whereas a new bud is a more compact rounded shape (as in the example below).

A new dahlia bud is rounded and compact

A new dahlia bud is rounded and compact

If you give a new dahlia bud a squeeze it will feel firm and you may be able to see the compressed petals within waiting to explode out into a fully formed flower. If you squeeze a spent dahlia head, it will feel squishy.

Where to cut

Once you’ve identified the right heads to remove, make sure you trace down the old flower stem and cut it off where the stem intersects with a leaf.

Where to cut off spent dahlia heads

Cut spent dahlia heads off with sharp secateurs or garden scissors just above the point where the flower stem intersects with a leaf

If you cut it off directly under the dead flower head you will be left with an unsightly flowerless stem. Multiply this by several flowerless stems and your plant will start to look quite ugly. Keep it trimmed down and you will have a neat bushy plant.

Keep deadheading

It’s amazing how quickly new buds form, flower and die, so deadhead your plant as often as you can. Your dahlia will reward you with a stunning supply of colourful blooms late into autumn or even into early winter. And if you have chosen a bee-friendly variety it will be a source of much-needed nectar late into the year.

Dahlias can provide much-needed late-season nectar for bees

Dahlias can provide much-needed late-season nectar for bees

Happy snipping!