The genus Hylotelephium may not be familiar to many of you but in fact, most gardeners have seen or are growing them without knowing it. That is because this genus was once part of the genus Sedum. The genus Sedum is quite large with representatives found pretty much worldwide. With more careful examination, plant taxonomists have recently started to split this genus into several new genera. The border stonecrops are one group which are now separated into their own genus called Hylotelephium. These include the popular 'Autumn Joy' and a host of other similar cultivars. About 35 Sedum species have now been moved to Hylotelephium. As gardeners, we are most interested in H. spectabile, H. telephium and the many hybrids between these two species.
The border stonecrops are indispensable for the late summer-early fall garden. For the most part, they are fail-safe and plants are attractive all season. Few pests and diseases bother them. They are very drought tolerant yet can tolerate surprisingly moist soil. Whether salty sites, acidic or alkaline soil, they seem to thrive. Being hardy to zone 2-3 they can be grown just about anywhere in the temperate zones of the world. All they ask for is full sun.
From the time the small, cabbage-like rosettes arise in spring until the first snows of winter, this plant deserves a place in the garden. While the original species have attractive grey-green, rubbery foliage, many of the new cultivars are more blue-tinted, purple or variegated. The flat-topped flower heads are reasonably showy with white, pink to nearly red flowers. These are highly attractive to bees and butterflies, making the border stonecrops a must-have for the butterfly or wildlife garden. The faded flower heads remain attractive well into the fall and even through winter if heavy snows do not crush them. Dried-flower enthusiasts can also take advantage of these versatile stonecrops.
As mentioned, there are two main species involved in the host of selections available today. Hylotelephium spectabile, commonly called ice plant, is a native of China and Korea with relatively large, fleshy, grey-green leaves and flat-topped clusters of pink flowers. Plants will reach 70 cm. Hylotelephium telephium, known as orpine or live-forever, is native from eastern Europe across to China and is also naturalized in many areas of North America. They are slightly smaller in stature than H. spectabile with smaller, more rounded flower heads.
Floral details of H. telephium vs. H. spectabile
There are currently over 40 selections of border stonecrops which have been derived from the two species noted above. Well over half of these have arisen in the last 10 years with, no doubt, more on the way!
First I'll start with some of the standard grey-green foliage types with pink flowers. The standard to which all others in this group are compared is 'Herbstfreude' (aka 'Autumn Joy'), the thumbnail picture for this article. This selection won an RHS Award of Garden Merit (AGM) in 1993. Also awarded that same year was 'Brilliant', a more compact version with brighter pink flowers held in huge flower heads. A new, dwarf version of these is 'Mr. Goodbud' which won an AGM in 2006. 'Emperor's Waves' and 'Jaws' have distinctly serrated foliage while 'Hab Grey' has leaves which are distinctly blue tinted.
Shown above are 'Brilliant' and 'Hab Grey'
Early on, plant breeders became very interested in H. telephium ‘Atropurpureum'. In itself, this selection has lovely dark purple foliage and many additional selections have been made from it, including 'Black Emperor', 'Purple Emperor', 'Postman's Pride', 'Red Cauli', 'Lynda Windsor', 'Picolette' and 'Xenox', just to name a few. ‘Purple Emperor', ‘Red Cauli' and ‘Xenox' won AGMs in 2006. The only drawback with H. telephium are the relatively small flower heads compared to H. spectabile. The first hybrid utilizing of H. telephium ‘Atropurpureum' was a cross of it to ‘Autumn Joy', resulting in 'Matrona'. This hybrid has purple-flushed foliage with the large flat heads of H. spectabile. It won an AGM in 2006. ‘Black Jack' arose as a sport of ‘Matrona'. It's spring foliage is grey, tinted purple but becomes dark purple by mid-season. 'Strawberries and Cream' had purple foliage with two-tone pink and white flowers...delightful!
Two awarded selections of H. telephium include 'Red Cauli' and 'Xenox'
Other notable purple-leaved stonecrops include 'Matrona' and 'Postman's Pride'
Flower details of 'Bon Bon' and 'Black Jack'
If variegated foliage is your thing, then there are border stonecrops to fit that bill too. 'Lajos' (aka 'Autumn Charm') is a white-edged sport of ‘Autumn Joy' while 'Pink Chablis' is a similar, more compact sport from ‘Brilliant'. Perhaps the most striking is 'Samuel Oliphant', a sport from ‘Matrona' whose grey-green leaves are edged cream to pale pink with dark pink-red stems! Stunning! Reverse variegation is also available. 'Mediovariegatum' is a selection of H. erythrostichum (a close relative of H. spectabile) whose leaves are creamy-yellow edged in grey-green. Equally striking is 'Beka' (aka 'Autumn Delight') a reverse variegation sport of ‘Lajos' which has yellow foliage edged in green.
Above are H. erythrostichum 'Mediovariegatum' and 'Autumn Delight'
Examples of variegated border stonecrops are 'Autumn Charm' and 'Samuel Oliphant'
Not to forget the white-flowered selections, among these you can choose from 'Stardust' or 'Iceberg', both with standard grey-green foliage. Most recently have arisen yellow-flowered selections. Among these are 'Sunkissed' and 'Citrus Twist'.
Shown above are 'Stardust', 'Iceberg' and below is 'Citrus Twist'
These are but the tip of the iceberg in the many selections of border stonecrops which are available on the market. Where can the plant breeders go next...perhaps purple foliage with a white edge...now that would be something! Keep your eyes open...such a combination is probably not that far away!
There are many people to thank for the photos used in this article: Chantell ('Black Jack'), colliwobbles ('Citrus Twist', 'Autumn Charm', 'Samuel Oliphant'), Happenstance ('Mediovariegatum', 'Stardust', 'Matrona'), kell ('Autumn Delight'), KevinMc79 ('Hab Grey', 'Red Cauli'), kniphofia ('Bon Bon'), ladygardener1 ('Brilliant'), RosemaryA ('Xenox'), and saya ('Postman's Pride', 'Iceberg').
(Editor's Note: This article was originally published on October 10, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questionsor comments.)