Black-Eyed Susans (Rudbeckia species) are hardy perennials that can be successfully moved and replanted. This process is most successful when the plant is not actively flowering or undergoing rapid growth. Success in transplanting depends primarily on careful timing and meticulous technique to minimize physiological stress.
Optimal Timing for Transplanting
The best time to transplant Black-Eyed Susans is when the plant is entering or exiting its dormant phase, which significantly reduces the risk of transplant shock. These two optimal windows occur in the early spring or the early fall.
In early spring, transplant just as new basal foliage begins to emerge, before the plant commits energy to vigorous vegetative growth. In the fall, move the plant after the flowering period concludes but well before the ground freezes solid. This timing allows the root system to establish itself while temperatures are still mild enough to promote root growth.
The actual move should occur on a cool, overcast day. This naturally limits the rate of water loss from the leaves, a process known as transpiration. Moving the plant during the heat of a sunny day places unnecessary stress on the tissues and compromises recovery.
Preparing the Plant and Excavating the Root Ball
Preparation begins approximately 24 hours before the move by thoroughly saturating the soil around the plant with water. A well-hydrated plant is better equipped to handle the physical disturbance and temporary loss of fine feeder roots during excavation. This pre-soaking also helps the soil adhere to the roots, creating a cohesive root ball.
To reduce the plant’s need for water after the move, prune the foliage back by about one-third. This reduction in leaf surface area decreases transpiration rates, allowing the plant to focus resources on root repair and establishment. Using a sharp spade, begin digging a trench outside the plant’s drip line, creating a generous root ball that is typically 8 to 12 inches wide.
The root structure of Black-Eyed Susans is clumping and not exceptionally deep, making it manageable to lift. Carefully work the spade beneath the root mass to sever the deeper roots, then gently lift the entire clump out of the hole, keeping the soil attached. If the plant is to be transported any distance, wrap the intact root ball in burlap or a plastic sheet to prevent moisture loss.
Replanting and Encouraging Establishment
The new planting site should be prepared before the plant is removed from its original location. Dig a hole that is approximately twice as wide as the excavated root ball, but only as deep as the root ball itself. This wider hole encourages new root growth into the surrounding, loosened soil.
Place the plant into the prepared hole, ensuring the crown—where the stem meets the roots—is positioned at the same level it was growing previously. Planting the crown too deep can lead to stem rot, while planting too shallowly can cause the roots to dry out. Backfill the hole with the excavated soil, gently firming it around the root ball to eliminate air pockets.
Immediately after replanting, give the Black-Eyed Susan a deep, thorough watering to settle the soil completely and provide instant hydration. For the first few weeks, maintain consistent soil moisture, watering whenever the top inch of soil feels dry to the touch. Monitoring for signs of wilting, which indicates transplant shock, may necessitate providing temporary shade during the hottest part of the day until the plant shows clear signs of new growth and establishment.