Growing agapanthus inapertus subsp. pendulus in a pot

Yes — agapanthus inapertus subsp. pendulus does well in a pot. Aim for a container around 20-30 cm (8-12 in) across: enough root room for it to reach about 1.2 m, without so much spare compost that it stays soggy between waterings.

Aim for a container 20-30 cm (8-12 in) across. Pot on when roots show through the drainage holes or growth slows noticeably — usually every 1-2 years for a plant this size. Move up one pot size only; jumping several sizes leaves wet compost the roots cannot reach, and that is what rots them.

Agapanthus inapertus subsp. pendulus needs sharp drainage, so this matters more in a pot than in the ground. Use a free-draining mix (add perlite, grit or bark to standard compost), always pick a container with drainage holes, and never let it stand in a saucer of water.

Containers dry far faster than open ground, so agapanthus inapertus subsp. pendulus in a pot needs checking more often than the general guidance of "Weekly during active growth and budding; taper off as foliage dies back in autumn" — especially in summer, wind, or a heated room. Check the top few centimetres with a finger rather than watering on a fixed day.