Sedum ‘Autumn Joy’
Considerable confusion has plagued the botanical name of Sedum ‘Autumn Joy’ for some time, but currently the most accurate reference appears to be Hylotelephium spectabile ‘Autumn Joy,’ though it is still sometimes listed Sedum telephium as well as Hylotelephium ‘Herbstfreude.’
In any case, the ‘Autumn Joy’ part of the name is perfectly descriptive. It puts on a show at the time of the year when our gardens can use a burst of color. As most perennials are slowing down for fall, this upright member of the succulent Crassulaceae family continues to bloom for weeks. Its large, rosy-coral flower heads stand about 15-18 in. high on a multi-branched plant about 2 ft. wide at maturity.
‘Autumn Joy’ is drought-tolerant and not fussy about soil as long as it is well-drained and not overly fertile. It is native to Asia but thrives in Sonoma County gardens.
Growth starts in spring with small, Brussels sprouts-like buds at the soil level. These gradually grow into thick fleshy stalks with paddle-shaped, mid-green, succulent leaves. The flower buds form in round clusters at stem tops in early to midsummer, starting out pale and gradually swelling as they broaden and darken in hue, ending up pinky bronze. Blooms continue for 6 weeks or so, fully opening from colorful buds at the end of August or beginning of September. If flower stalks are left standing until spring, deep mahogany seed heads give the garden winter interest and also provide a food source for birds as they sit on the large spent flat heads and pull out seeds.
Maintenance is minimal. In late winter or early spring, either cut or break off the stalks at ground level where new buds are forming. When the lower clusters of buds widen substantially at ground level, they can easily be dug up and divided to make more plants.
As with other sedums, ‘Autumn Joy’ can be an element among other low-water flowering perennials in a rock garden or among ornamental grasses. Although it often appears on deer-resistant lists, deer are frequent predators in fall as native vegetation dries up. Bees and butterflies are nonstop visitors for many weeks. Bees rely heavily on this and other plants that produce late-season nectar.
‘Autumn Joy’ is easy to care for, but it can be tempting to give it too much water. Its primary needs are full sun and lean soil. If grown in soil that is too rich, in too much shade, or if given too much water, it will flop over when the flower heads get heavy. This can be avoided by reducing the water, staking the stems, or cutting the plant back by ½ in May or June. An early pruning results in increased branching on shorter stems. Flowering may be somewhat delayed, however.
Insects and diseases are generally not a problem, although sometimes sedums will get an infestation of black aphids, less likely if they are sited in full, all-day sun. Strong shots of water from a hose nozzle will knock them off.
A similar sedum, ‘Autumn Fire,’ is said to be an improvement of ‘Autumn Joy’ and is becoming more available in nurseries. It has larger and longer-flowering blossom heads that stand on stouter, stronger stems.