Space plants at least 1 foot apart in the garden; they will gradually fill in and form clumps. If you wish, you can cut back the stems in the late spring to limit their height and promote thicker, bushier growth. Some gardeners cut down the stems in the fall after the foliage begins to depreciate, but the stems can also be left to provide winter interest and cut down in the spring before new growth starts. Birds will feed on the dried flower heads over winter.
Light
Autumn Joy prefers to grow in full sunlight, meaning at least six hours of direct light on most days. Shady conditions can make the plant leggy and reduce flower production. But in very hot summer climates, your plants might appreciate some shade in the mid-afternoon.
Soil
This plant thrives in sandy or gravelly soil with sharp drainage. But it will tolerate loamy soil provided it is well-drained and not allowed to remain constantly damp.
Water
Autumn Joy does not need much water and has excellent tolerance for drought. Even in the heat of summer, light watering every two weeks or so is sufficient. More frequent watering can cause the roots to rot.
Temperature and Humidity
This plant tolerates a wide range of temperatures. It can thrive in extreme heat, and it often continues to look attractive in the fall until it has been exposed to a few frosts. Then, it dies back and goes dormant for winter. Humidity is typically not an issue for the plant as long as the soil doesn’t retain excessive moisture in areas with high humidity.
Fertilizer
Autumn Joy grows well in poor soils, so feeding is typically not necessary. The plant might like a light spring feeding with a balanced fertilizer if you have very poor soil. But excessive fertilizing can cause leggy growth.
Types of Stonecrop
These are some other stonecrop varieties that are closely related to Autumn Joy:
Hylotelephium ‘Autumn Charm’: This plant has similar blooms to Autumn Joy but has serrated gray-green leaves with cream edges. Hylotelephium spectabile ‘Autumn Fire’: Autumn Fire has larger flower heads and stronger stems than Autumn Joy, and it blooms for a longer period.Sedum ‘Mr. Goodbud’: This hybrid is a good choice if you want darker, more purplish flowers. It blooms a bit earlier than Autumn Joy.Sedum spectabile ‘Hot Stuff’: This is a more compact plant than Autumn Joy, growing only 10 to 12 inches tall with pink and purple flowers.Sedum spectabile ‘Iceberg’: This plant has mainly white flowers and is a slightly smaller plant than Autumn Joy, growing to a maximum of about 16 inches.
Pruning
Autumn Joy stonecrop might benefit from tip pruning in the spring to promote better growth, but in most cases, simply let the plant thrive on its own and you’ll be rewarded with copious blossoms.
Propagating Autumn Joy Stonecrop
This plant is extremely easy to propagate through stem cuttings, even if they are simply stuck into the ground. Even individual leaves fallen on the ground will sometimes take root and grow into full plants. This is how it’s done: You also can divide sedum plants to propagate them:
How to Grow Autumn Joy From Seed
Since Autumn Joy is a cultivar, no seeds will grow into a plant that is identical to the parent. Therefore it is not recommended to use seeds for propagation.
Overwintering
This plant is hardy to USDA zone 3 and does not need protection even in climates with harsh winters. It will die back, assuming you do not choose to prune it back in the fall, and will bounce back in the spring with fresh foliage and blossoms.
Common Pests and Plant Diseases
Autumn Joy stonecrop is remarkably free of most common garden pest and disease problems, though the fleshy leaves can be susceptible to damage from slugs and mealybugs. These can largely be controlled by keeping the ground free of debris, including mulch. You also may use neem oil on a severe infestation if necessary. Furthermore, occasionally you might see deer nibbling on the fleshy leaves of the plants.
How to Get Autumn Joy to Bloom
Make sure your plant is getting at least six hours of full sunlight each day, and that it’s resting in well-drained soil. Soil that is very rich in fertilizer or compost can actually be a detriment to this plant, as it will want to grow more foliage and stems than blooms. Shade will also prevent blooms from appearing on your plant. Finally, remember that the soil can’t be too wet, as the plant will rot and then, of course, there is no hope at all for the lovely blooms.
