Planting Guide: Upright Sedum ('Autumn Joy,' 'Blackjack,' etc.)
Upright sedum, also known by its botanical name Hylotelephium spectabile, is a gardener's favorite for its incredible resilience and stunning late-season display. This guide will walk you through the proper steps to ensure your upright sedum thrives.
Step 1: Selecting the Right Spot
Sunlight is Key: Upright sedum requires at least 6-8 hours of direct sunlight per day to grow strong, upright stems and produce vibrant flowers. Planting in too much shade will cause the stems to become weak, leggy, and "flop" over.
Good Airflow: Choose a location with good air circulation to help prevent powdery mildew, which can occasionally affect the foliage.
Step 2: Preparing the Soil
Excellent Drainage is Non-Negotiable: Sedum is a succulent and will rot in soggy soil. It prefers a lean, rocky, or sandy soil.
Soil Amendment: If you have heavy clay soil, you must improve its drainage. Mix in coarse sand, gravel, or perlite to the planting area. A good rule of thumb is to amend a hole that is at least twice as wide as the plant's root ball.
Avoid Over-Fertilizing: Sedum does not need rich soil. Adding too much compost or fertilizer will lead to lush, but weak, growth that is prone to flopping.
Step 3: Planting Your Sedum
Timing: The best time to plant upright sedum is in the spring or fall, when the weather is mild.
Dig the Hole: Dig a hole that is as deep as the plant's root ball and at least twice as wide.
Remove from Container: Carefully remove the plant from its nursery pot. Gently loosen the roots with your fingers if they are tightly bound.
Position the Plant: Place the plant in the center of the hole, ensuring the top of the root ball is level with the surrounding ground.
Backfill the Hole: Fill the hole with your amended soil, patting it down gently to remove any large air pockets. Do not press too hard.
Water In: Water the plant thoroughly to settle the soil.
Step 4: Post-Planting Care
Watering: Water new plants regularly for the first few weeks to help them establish. Once established, sedum is extremely drought-tolerant. Only water during periods of prolonged heat or dry spells.
Mulching (Optional): You can apply a thin layer of gravel or stone mulch around the base of the plant to help retain moisture and keep the crowns dry, but avoid organic mulches like wood chips, as they can hold too much moisture and cause the crown to rot.
The "Chelsea Chop" (Optional, but Recommended): In late spring to early summer (around late May or early June), you can cut back the stems by about one-third to one-half. This simple pruning technique encourages bushier growth, stronger stems, and a more uniform plant that is less likely to fall open later in the season under the weight of its flowers.
Step 5: Winter Care
Leave the Foliage: Do not cut back the brown flower heads and stems in the fall. They provide winter interest, and the spent foliage helps protect the crown of the plant from cold and frost. The dried flower heads also provide seeds for birds.
Cut Back in Spring: In early spring, before new growth begins, cut the old, dried stems back to the ground. This will make way for the new growth.
By following these simple steps, you can ensure your upright sedum becomes a long-lasting, low-maintenance, and beautiful fixture in your garden.