Care Guide for a Potentilla (Potentilla fruticosa / Dasiphora fruticosa) Bonsai
The Potentilla, or Shrubby Cinquefoil, is a hardy deciduous or semi-evergreen shrub prized for its bright, continuous flowering throughout the summer, excellent fine ramification, and exfoliating bark.
Placement and Temperature
- Sunlight: Potentilla requires full sun to encourage dense foliage, short internodes, and prolific flowering. Insufficient light will result in sparse growth and few blooms.
- Temperature: It is extremely hardy and cold-tolerant and must be kept outdoors year-round. It easily satisfies its dormancy requirement. Protect the roots in the pot from deep, sustained freezing below -10C.
Watering and Feeding
- Watering: Water thoroughly when the topsoil is dry to the touch. Potentilla is relatively drought-tolerant once established but performs best with consistent moisture, especially during its long flowering period. Ensure excellent drainage.
- Fertilisation: Feed consistently throughout the active growing season (early spring to late summer). Use a balanced fertiliser or one slightly higher in phosphorus (P) during the summer to support continuous flower production. Stop feeding in autumn.
Pruning and Repotting
- Pruning: Potentilla flowers on new wood formed during the current season.
- Structural Pruning: Done in late winter/early spring during dormancy.
- Maintenance Pruning: Use the clip-and-grow method throughout the summer. Prune back new growth to 2-3 leaves to refine the pads and encourage more ramification, which in turn leads to more flowering points.
- Repotting: Repot every 2–3 years in early spring just as the buds swell. Potentilla roots vigorously and develops a dense, fibrous root mass. Reduce the root ball by up to one-third.
- Soil: Use a fast-draining, well-aerated mix (e.g., Akadama, Pumice, Lava Rock).
Wiring
- Timing: Wire in late winter/early spring.
- Wood: The branches are pliable when young but become stiff and brittle quickly, especially the older wood.
- Removal: Check the wire frequently (every 4–6 weeks) and remove it quickly, as the bark is soft and scars easily. Use guy wires for heavy bending on older branches.