Q.Large Pot Bound Agapanthus
Variety Queen Mother. Wasnt able to divide for last two years. very large strong growth six to eight inches above the pot rim showing many green roots on surface and up rhizomes. Managed to remove from pot and divided but not sure how much need leaving above new soil surface. None of my pots are deeper then 14 inches and from old base roots to where new green shoots are is over 24 inches. Can bottom half of root ball be cut away?

Certified GKH Gardening Expert
You can knock out some of the soil and trim away dead roots. If the roots are very long, it shouldn't hurt to clip them back some. That should reduce the size of your root ball so you can replant.
https://www.gardeningknowhow.com/ornamental/bulbs/agapanthus/dividing-agapanthus-plants.htm
https://www.gardeningknowhow.com/ornamental/bulbs/agapanthus/dividing-agapanthus-plants.htm