Dividing Pacific Coast Irises
Dividing Pacific Coast Irises-First, why would you want to divide them? We’ll when they get really big, after several years, they produce fewer flowers. Dividing them between 4 and 6 years keeps up the flower production. The other reason to divide them is just “greed”. If you have a favorite, then two favorites are almost twice as good as one favorite. Now let’s say you have a few picked you that you’d like to divide, what next.
Well, you have to divide your PCI’s at the right time of year. In Southern California that’s between mid November and early January. I’ve tried doing this earlier and later and it doesn’t work. I’m embarrassed to admit I’ve done this more than once. You’re almost ready for action. I would water your irises a couple of days before you divide them to stimulate some root growth. Next, dig them up from the outside and try pulling them up intact in one large clump. Shake the dirt then wash off with a garden hose; you can’t let the roots dry out. Place the large clump on a table and divide them. It’ll be really easy to see where they should be divided. You’ll see individual rhizomes, which tells you where to divide/tear. Now take the pieces that you’ve separated and let them sit in a solution of 1% to 2% bleach and water for 5 minutes or so. Rinse off the bleach and water then let them sit in a bucket of water while they are waiting to be planted. You want to plant within an hour or so.
Ready to plant! PCI’s in Southern California need to be planted in a shady place. You can plant them back in your garden or a container. In either case the soil needs to drain really well and you have to plant “high” so the water doesn’t drain and sit in the crown or they will rot. You can incorporate a bit of bone meal into the planting mix or some time release fertilizer. Read the label on the fertilizer and divide by 2. Now water!!!!!! You want keep up the watering about 1x per week so they don’t get too wet but they don’t dry out. If it rains you’re most likely off the hook for between 1 and 2 weeks. And you should also get flowers from about half of your new divisions in the first spring.