Dividing Siberian irises

Remove old growth to keep clumps productive

- Ruth

WE have a couple of stands of mauve Siberian irises that flower reliably and beautifully in late spring and early summer. They are going over now and one stand in particular has lost its shape, becoming bare in the centre as the stems grow in a circle around the fringe, like a monk’s tonsure.

To return them to a robust and productively flowering state I need to lift and divide the clump, removing the old unproductive central core before replanting the divisions at the same depth they were growing before.

Siberian irises grow well in fertile soil that is damp but not waterlogged, and they like full sun or partial shade.

If your soil is thin and poor, and doesn’t retain water well, dig in a generous amount of well-rotted compost or manure before planting.