Collecting PCI Seeds
When pollination is successful, after the flower fades, the ovary will begin to grow. Normally, the seedpods ripen in about nine weeks. As they ripen, the pods go from green to yellowish to brown. If pollination was not successful, the pods do not enlarge and ripen, they wither and turn brown early.
In the garden, when the pods are ripe, they split open in three sections, throwing the seeds out — typically on a warm day when you are not around to collect them! To catch the seeds some gardeners tie mesh organza bags over pods to contain seeds as they ripen. These bags are open mesh, so water drains and dries quickly, keeping the seeds together and in good condition.
Other gardeners prefer to pick the stems early, at 8-9 weeks, and dry the seeds in envelopes. At this point the pods are usually developed enough to hold fully mature seeds, even when these pods are not yet brown. The seeds inside are typically viable when the pods are cut open.
After collecting, you may sow the seeds when fresh, or store them. To store, seeds should be air-dried in paper bags for a week or so in a warm dry place, and when thoroughly dry, held in a cool, dry place.
PCI seeds can live for several years when dried and stored properly. Although the germination rate decreases over time, members have successfully germinated seeds that were twelve years old!
SPCNI holds a seed exchange every winter. Members donate seeds to be shared with all members of SPCNI as a way to raise funds for the society.
Germinating PCI Seeds
Pacific Coast Iris (PCI) seeds require a period of cool, damp conditions to germinate, so the optimal time to germinate seeds depends heavily on your local climate.
In Northern California and the Pacific Northwest, this occurs naturally in late summer to early fall where seeds can be planted directly outside without any special treatment when seeds are fresh. Seeds in this region can also be sown late winter to early spring when moderate temperatures return to your garden. Seeds can be presoaked in water for up to one week prior to sowing if the seed pots are not going to be placed outside and exposed to the elements.
In colder regions, sowing seeds in late winter or early spring is often more successful, as it helps seedlings avoid harsh cold during their early growth period in late winter and early spring. If you have access to a cool (60°F or below), frost-free cold frame or greenhouse, you can sow PCI seeds throughout the winter.
In warmer climates, fall sowing allows seedlings to establish and grow larger before the stress of summer heat.
Cold stratification can help improve germination and start the growing season early to maximize growth before the summer heat. Holding seeds at 40 F for 20 days has been found to promote rapid and even germination. Limit the chill to 20 days in the refrigerator and make sure seeds have enough moisture.
Sow the seeds at a depth of ¼ inch in a well-draining, in neutral to mildly acidic potting mix. Place the containers in partial sunny conditions and water well. Then water between 1x/ and 2x/ week. Some gardeners cover seeds with ¼ inch layer of #3 poultry grit or coarse sand to protect seeds and prevent damping off after they sprout. And don’t forget to label your pots! Do not rely on your memory to recall which seeds were planted where, and when.
Seeds appear to germinate most readily at temperatures between 40 and 60 F. Higher temperatures inhibit germination in several experiments: starting PCI seeds at 70 F resulted in no germinations; colder temperatures (below 40 F) reduced germinations. Gene Loop and Lewis Lawyer researched germination inhibitors in the 1990s and concluded that PCI do not have germination inhibitors.
Note: Two species definitely prefer 50 F and cooler temperatures: Iris innominata and I. tenax. These are also the most cold-tolerant PCI species. Iris munzii germinates as well at 60 F as it does at 40 or 50 F, so this species may tolerate slightly warmer temperatures.
Fresh PCI seeds typically germinate in a few weeks following cold stratifying. Older seeds may take longer. Seeds may take 2 to 4 months or longer to germinate. If they don’t come up in the first season, consider leaving them until next spring where new seedlings often pop up when left to the elements.
Growing PCI Seedlings
When the seedlings are a few inches tall, transplant them into individual containers or into the ground with a small amount of time-release fertilizer. Take care not to disrupt roots when transplanting.
Some gardeners transplant from a seedling pot to 4 inch pots, and then on to 1-gallon pots in a few months to give each young plant room to grow rapidly. Other gardeners transplant once into 4 inch pots, then into the ground the next fall. PCIs started indoors should be hardened off for a time outdoors in their pots in a sheltered spot before transplanting.
Once plants are fully rooted in their pots, they can be planted out into the garden for flowering in a year or two depending on soil nutrient levels. In extreme conditions it is best to separate seedlings into individual pots to grow until established, then plant out.
Individual plants should be set out 1 to 2 feet apart at the same depth that they were growing in the pot. For the first year or two, seedlings are very forgiving of growing conditions and able to tolerate crowding. After this, they may die rapidly if not given their preferred conditions.
You have come full circle with your PCI, from plants to flowers to seeds, to new plants. Congratulations, and good luck with the next generation!
Looking to purchase seeds? Visit our Seed Exchange page for more info! (Link Seed Exchange)
What to learn more about how cross pollinate Pacific Coast Iris? Visit our Judging and Hybridizing Pacificas page. (Link to Hybridizing Pacificas)
Need tips on cultivating Pacific Coast Iris? Check out our Growing Tips.
References
Lawyer, Adele. 1996. Seed: Harvesting and planting, SPCNI Almanac, Fall 1996, pp 10-13.
Lawyer, Lewis. 1995. More on Seed Germination, SPCNI Almanac, Fall 1995, pp 10-14.
Loop, Eugene. 1994. On the germination of PCI seeds, SPCNI Almanac, Fall 1994, pp 5-7.