Sedum x 'Autumn Joy', or commonly called Autumn Joy, is an herbaceous perennial from the family Crassulaceae. It has been determined by some to be one of the best perennials for any garden. It is also a favorite of butterflies and bees. Although generally pest free, Autumn Joy can suffer from some pests in unfavorable growing conditions.
Autumn Joy is United States Department of Agriculture (USDA) hardy in zones 5 through 9. It can grow 18 to 24 inches and prefers full to part sun. It grows best in acidic, slightly alkaline sand, or clay soil. Green buds appear in late summer that somewhat resemble broccoli heads. Progressively, they turn light pink and mature to a darker pink, and finally reach a rusty red to brown color. The leaves are very attractive, with a grayish green color. They attract butterflies and bees to any garden. They also make excellent dried flowers.
Autumn Joy can be planted in masses by itself to create huge drifts. It can also be used in beds and borders. It compliments other plants such as the black eyed Susan, Russian sage, or white coneflower. It can also be used in containers, and the dried heads are a good addition for flower arrangements.
The sedum varieties, including Autumn Joy, can occasionally be bothered by certain pests. A couple examples include aphids, fungus gnats, and snails and slugs. Aphids attack the sedum in spring and summer. They feed on the stems and leaves with their piece sucking mouth parts and suck out the plant juices. The fungus gnats can infest garden soil and container mixtures. The larvae will then feed on organic matter and the roots of a plant. Both the larvae and adults can damage plants. Snails and slugs are not considered insects but rather mollusks. Both pests feed during the night and leave behind a slimy trail.
Aphids damage leaves with their piecing ability. They suck the sap and other nutrients out of the plants, leaving behind honeydew, or a juice with excess sugar. The honeydew attracts other insects to the plants. They can also inject toxins that will deform plant tissue. Fungus gnat larvae can damage plants by feeding on the roots, thus stunting plant growth. Snails and slugs cause damage by making holes in the leaves and feeding on the veins between the leaves. The damage can be severe, especially in the spring and fall when conditions become wetter.
Aphid control can be accomplished by spraying insecticide solutions. Fungus gnats can be controlled by good cultural practices. They thrive under wet conditions and where there is an abundance of decaying plant debris. It is best to avoid overwatering and provide good drainage. It is also recommended to allow the surface of the container soil to dry between watering. Insecticides rarely, if ever, are used to control these flies. Snails and slugs can be controlled by taking away their hiding places, such as under boards or large stones. Snails can be picked off by hand but this can be difficult and unpleasant, especially with slugs. Diatomaceous earth, a natural compound, can be used for control. They are also turned off by oak leaf mulch and other plants like artemisia.