Iris seed starting basics

 This post is meant to be a quick stab at the topic of starting iris seeds.

On the surface, this should be straight forward. Stick seeds in dirt, watch them come up, poof! Irises.

My first experiments with growing irises from seed started with Siberian iris, 'Caesar's Brother' which had plentiful seeds the year before.

 

And the truth of the matter is that it is a little bit more complex than that... but not that terribly difficult.

The first question is where does one get iris seeds? What sort of iris seeds are you wanting to try to grow? Do you have enough room to grow a lot of plants or just a few? Wait, I thought I said this was going to be simple. Okay, the simplest place to get iris seeds is from your own irises. If bees have pollinated your plants, you'll see lovely swollen seed pods where the flowers used to be. Let those seed pods dry until just before they crack open. Then harvest them (with notes about what the name of the variety you gathered them from [this is the pod parent]) and let them dry in a shallow dish or a paper bag for a few more weeks until they are completely dry. Then those seeds can be stored in a labeled envelope until ready to plant. You might be able to swap seeds with a fellow iris grower nearby too. Alternately, you can buy iris seeds from places like SIGNA (Species Iris Group of North America) http://www.signa.org, NARGS (North American Rock Garden Society) https://www.nargs.org/ or even places like Seed Savers Exchange or seed swapping groups on Facebook. 

The topic of what type of iris seeds to grow could be its own article. Let's jump back to HOW to get these seeds started. 

iris versicolor seeds, from SIGNA in 2023

 

Irises need just a little special treatment to jump-start germination. There is a coating on iris seeds that inhibits germination... and that coat needs to be washed off. Once the inhibition coat has been rinsed off, the seeds need a lengthy cold period called stratification. This seeds to a cold, moist period that helps prepare seeds to germinate once the weather warms up. There are a few ways to get seeds through this rinsing and stratification process. The simplest is to plant your seeds outdoors in pots usually in late fall when you're planting bulbs. Plant them twice the depth of the seed, not too deep, (dont forget your label!), then water them and leave them be till spring. Many years you'll get some germination in early spring, with the caveat that without washing off the inhibition coat you might see some germination staggered over the summer and into the following year. 

 

winter-sowing in milk jugs, some closed and others wide open

Some gardeners have successfully started iris seeds with the winter-sowing method of using gallon milk jugs with seeds stratified throughout the long winter. 

Alternately, if you wash your seeds by soaking them and changing their water daily for about 10 days, then store them in your fridge (in moist but not wet, peat moss in a lidded container for about 90-100 days, you'll see a much higher rate of successful germination. Chuck Chapman's website has fantastically detailed instructions on this process. http://www.chapmaniris.com/Sci-HappySeeds.htm

Iris seedlings in milk jugs in early spring, with the tops of the jugs removed. Some of the seedlings have been moved to module trays (top right).

Once you have your germinated seeds they will need gentle care until they are ready to transplanted into a bed where they can grow for 2-3 years before you see the first bloom. Keep in mind, these seedlings will not be clones of the parent, but instead they will be crosses of that parent that set the seed, and whatever plant donated the pollen. No matter what, it will be a unique iris. Give it a few years in your garden to see how it develops, multiplies, blooms, etc. It might fail to impress the first year it blooms. Or you might be pleasantly surprised. 

Iris seedlings, transplanted into the garden in July. Note: each seedling has a label because I am growing many different varieties in a limited space.