Tis the season…. it’s Fall, the rains have begun and the species pacific coast Irises’ roots are growing. This is the time to divide. I dug about half of a clump leaving the remainder undisturbed. I cleaned the soil away from the other portion wiggling, teasing, pulling, even cutting a few of the rhizomes, to separate them out into nice size starts.
I tend to trim the old rhizome back. They are long and relatively thin, less than pencil thick. Active meristem, where growth is initiated, is toward the actively growing tip of the rhizome. The rest of it contains starches that will support growth but cannot initiate new growth…meaning that you can’t cut it into smaller pieces and grow new plants from it. In this they are much like other rhizomatous Iris. Look for active growing points. They should be obvious with white, pink and green tissue. The old rhizome will help stabilize your divisions when you plant them in their pots, but don’t be frightened of trimming them back. The picture shown here shows how the rhizome can be relatively long and thin with numerous branchings.
Then I trim the top back to about a third or half its length to reduce the chance of desiccation, pulling away the old dead leaves away from the pink bases as I went.
You can see the nice healthy white root growth that’s initiated this fall already. These will keep growing over the cool moist winter establishing themselves in their pots. I’ll get enough rhizome into each pot so that they can quickly fill out and be more likely to flower this following spring. Just keep them moist over the winter and don’t let the pots freeze. Freezing temperatures are OK as long as you don’t turn them into ice cubes. Always keep in mind that these go dormant in the summer and that disturbing the roots can be fatal to these then. Remember, these aren’t like your bearded Irises.
[For those of you who don’t know that is Iris x pacifica ‘Simply Wild’ growing in the lower portions of a Fabiana imbricata ‘Violacea’ that tops my masthead.]