At its best:
Jun, Jul, Aug, Sep
Cover the bottom of the container with crocks, to stop the compost falling out of the drainage hole.
Fill the pot thwo-thirds full with compost.
Arrange the plants in the container, starting with the phormium, followed by the heather and heuchera, and finally squeezing in the carex. Fill around the plants with compost and firm in well.
Water the pot thoroughly and allow to drain before moving it to its final position.