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Time to Divide Your Pacific Coast Irises – How To

Time to Divide Your Pacific Coast Irises – How To!

Bob Sussman 10/24/18

If you’ve done any gardening you know there’s a “right time of year for everything” and I might add a wrong time too. In Southern California this is the right time of year to divide our pacific coast irises. This goes on from mid-October through the end of November. Before or after the time frame it’s not so successful. This varies a little bit from year to year as well as geographic location. Up the coast it might be a little earlier and in the Southern Hemisphere exactly 6 months later as one might guess. You likely will want to divide your pacific coast irises every 4 to 6 years. If you don’t the flowers can tend to be fewer and smaller.

Okay, now how does all this work? First, figure out which ones you want to divide. Look for multiple fans – groups of leaves. I make sure that there are plenty of labels for each of the divisions because it’s really easy at this stage to get them mixed up.

dig up you pacific coast iris or take it out of the 5-gallon pots, which is how we store them. Dig deep enough to make sure you get all the new “white” roots- so maybe 1’ should be fine. Second, shake off all the soil and begin separating them and they should look as shown below.

You can see from the clumps above the natural divisions/rhizomes with the new white roots coming down indicating they are beginning to grow. Third, after your rhizomes have been separated soak them in a mild bleach/water solution about 1 or 2 oz/gallon of water. Let them sit for a couple of minutes to sterilize the tear then pull them out of the water and rinse them off with clean water and begin potting them or planting them out. Below is what they should look like before you plant them out or put them up.

Fourth and finally you’re ready to plant or put them in a pot/container. We put them in small containers with a very well draining mix and give them the secret drench of the anti-fungal and growing solution. You can try diluted 1oz/gallon of hydrogen peroxide and some balance fertilizer and that will work just fine too. Water 2x/week – since we use a very well draining mix or 1x/ week for heavier soils.

Wait until spring and they should bloom first year!

That’s it….that’s all there is to it!

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Featured Plant



Botanical Name

Iris germanica TB 'Bernice's Legacy' Re

Common Name

Bernice's Legacy


Flower Color


Mature Size

2-1/2 tall × 2 wide

Climactic Requirements


Full Sun / Filtered Sun


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