Pacific Coast Iris Germination 2014

[GordonT]

In 2013, I decided to follow a recently recommended method to improve my germination rate, as it had been quite disappointing in 2012 Kathleen Sayce ran an experiment documented in volume 40, Spring 2012 edition of the SPCNI Almanac. This year I followed the same technique. I used a nail file or simply my fingernail, to scratch away as much of the seed coat as possible, on every seed. The seeds were placed in leakproof ziplock bags, partially filled with water, and sealed. These were left at room temperature, out of direct sun (but not in darkness). The water was replaced once or twice during the month long soak- some batches of seed caused the water to discolour  at first, as plant extracts leached out of any remaining seed coat.


Over the past two weeks, seeds have begun to germinate. As soon as a bag shows signs of germination, the contents are transferred to seed flats for growing on. Germination rates have greatly improved since I began using this method, sometimes verging on nearly 100% germination, when my first attempts barely reached 40% success.

[meanie]

I need to say a thank you for drawing this to my attention! I fail with Iridaceae regularly, although I have been successful with some members of the family (mostly Ferraria).
Diplarrena is one that is especially troublesome, even with fresh seed. So having read your post I decided to employ this method and after just over a week the first two D.latifolia are germinating. Thanks

[Maggi Young]

I need to say a thank you for drawing this to my attention! I fail with Iridaceae regularly, although I have been successful with some members of the family (mostly Ferraria).
Diplarrena is one that is especially troublesome, even with fresh seed. So having read your post I decided to employ this method and after just over a week the first two D.latifolia are germinating. Thanks

  Result! 

[Brian Ellis]

Thanks for sharing this with us Gordon, last year I had terrific germination in moist vermiculite, but not so this year so am now giving them a soak

[Lesley Cox]

The convenor of our local Iris Group has an odd method which I'm about to try. The seeds are put, with label, in a small cotton bag then a number of little bags stacked upright in a small bowl or cup. A cup of cold tea is added and left for 24 hours, then changed each day for a total of 4 days. The bags are drained properly and germination has often started already but if not, the plumped up seeds are transferred to a pot of damp mix and proceed to come up like hairs on a dog's back. Any already germinated are plced in small pots and covered lightly to grow on. It really works. I saw them at the weekend. Wondering if it would help for oncos.

[GordonT]

Hi Leslie, and a belated Happy Birthday to you. Your method sounds similar to another I have heard described... Place the seeds in a muslin or cotton bag, and suspend the bags securely inside the tank of a toilet below water level. The water is changed with each flush.

I haven't tried this technique, but use another method for I ensata, and the Sino Siberian group. These get scattered on moist paper towel, then into ziplock bags in the refrigerator for 2 to 4 weeks. When I removed the last batch of ensata seed from the fridge, I experimented, and scratched off the spongy 'exocarp' (wrong term, but best I could think of) surrounding the true seeds of half the lot. Each batch of seeds were planted and the pots went into our unheated greenhouse. Rapid germination was observed on the seeds freed of their exocarp.

This year I decided to remove the exocarp on some seeds before they went into the fridge (Iris bulleyana, chrysographes, delavayi, forrestii, and wilsonii) to see if this would speed germination even further. Will report on what I discover. The more I play around with these seeds, the more I think that the exocarp is where most of the germination inhibitors are stored.

[Lesley Cox]

I think you're right Gordon, saying the inhibitors are storred in the exocarp (I'm not surre of the right term either) and especially it's true of such things as Daphne and Trillium for example. Both these are candidates for the "hanging in the toilet tank" treatment. The frequent flushing of water over them really does seem to wash away the inhibitors. A few years ago I had Trillium seed germinate well soon after being drained, having spent a full year or more, unseen in a bucket of water which had been gradually filled with windblown leaves and rain but been negected in various cleanups.

I'd be very interested to hear of any experiments you try on iris seed. I'll try the ensata one, an Auckland friend having recently sent me a total of about .25 of a kilo of various forms of ensata seed. I plan to plant the whole South Island with the results.

[Jeffnz]

I have improved my germination rates of PCI seed by soaking the seed for4-5 days in a solution of dilute hydrogen peroxide then sowing.

[Otto Fauser]

as I get more self sown seedlings from my PCI than I can accommodate in my garden ,I do not have to worry to improve germination rates .

[Tony Willis]

I just sow them when ripe and they germinate freely in spring having been left out over winter. Nothing special needed.

[Jeffnz]

I am sure that freshly harvested seed sown before desiccation sets in will always have a higher germination rate than older seed. Most of my PCI seed is from northern hemisphere sources and desiccation is an inevitable possibility.