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Grow Siberian iris from seed

I have several Siberian iris pods that have dried and split and produced seeds. Can I plant them to grow new irises? When is the best time to plant?

Siberian iris croppedAfter the irises bloom in the spring, they may form seed pods, and those ripe seeds (which should be dark and shiny) can be saved and planted to grow new irises. But they require specific conditions to germinate successfully, including a period of cold weather, so the best time to plant iris seeds is in late fall and winter.

Iris experts suggest two ways of germinating iris seeds. This information comes from Margie Valenzuela of the Tucson Area Iris Society and Sally G. Miller at the Dave’s Garden online community of gardeners:

Soak the seeds in water for at least 48 hours, or for several days, changing the water every day. This causes the seeds to plump up and allows them to germinate faster. Plant the seeds about a half-inch deep, about a half-inch apart in a planter box filled with seed-starting potting mix, and keep the soil moist (but not wet) at all times. You may want to cover the container with wire mesh to keep squirrels from digging in the pot. You can also plant the seeds directly in the ground this winter, in a prepared bed. When they begin to germinate, iris seedlings look a bit like grass, but the leaves soon acquire their typical flattened growth pattern.

Other experts provide information about growing seedlings indoors, under lights. They still need a period of chilling – about 12 weeks in the refrigerator, after soaking the seeds in a sterilizing solution of one part bleach and ten parts water. After they’ve had their chill, plant the seeds in seedling mix and grow them under fluorescent lights indoors, moving the seedlings to the prepared garden bed as weather permits, and keep them well-watered during the first year.

Irises grown from seed may not bloom the first year. And when they do bloom, you may find they don’t emerge as the exact plant that grew them – they likely will be interesting hybrids, fertilized nature’s way by bees and other pollinators.

When will Siberian irises bloom?

Question: I received several clumps of Siberian irises from a friend last spring. I didn’t plant them right away, but when I finally did plant, I watered them well and added some fertilizer. They looked a bit limp for awhile and finally recovered, but they didn’t bloom. Should I expect blooms this year?

siberian irisIrises are among the season’s loveliest flowers. The big, beautiful bearded irises that are putting on such a show right now seem to be unconcerned about when and how often they’re moved and usually bloom without fussing. But according to the American Iris Society, Siberian irises don’t like to be disturbed once they’re established, so they may sulk for awhile when they’re moved. If the roots dried while they were waiting to be planted, that may have dealt them another blow. AIS cautions that the roots should never be allowed to dry out while they are out of the ground, and they should be watered heavily after they are transplanted.

Last year, the newly planted irises may have spent the spring and summer getting a strong root system established. By this year, you may have a few blooms.

In general, here is what Siberian irises need to do well: slightly acidic soil in a sunny location (though AIS says they can tolerate light shade), and regular moisture. While the rhizomes of bearded irises should be planted almost on top of the soil, Siberian and other beardless varieties should be set slightly deeper in the ground. All beardless irises should be fertilized regularly.