Onco and Juno Iris

[Erika]

Hello,

I live in Toronto Canada and have been growing I. paradoxa for approx. 6 years,  I. kirkwoodii for 2, and Iris rosenbachiana for 1 year. All are mature and should be blooming. I grow them successfully in my cold greenhouse, but cannot seem to bloom them. Could anyone offer some advice or suggestions? My mix is grit, pumice and coarse sand. I give them some moisture during the winter, and keep them dry in summer.

Thanks,

Erika

[ebbie]

Hello Erika, I have a couple of candidates that bloom rarely, too - Iris lycotis, Iris nusairiensis. I think them lack the light in the winter and maybe the heat in summer. Could that be with you?

[Maggi Young]

Hello Erika, welcome to the Forum!

I'm not growing these Iris nowadays but there are others here who have great success with them- I'm sure they'll be able to help.  Ebbie's suggestion seems a good starting place.

[Erika]

Hello Maggi and Ebbie. My greenhouse is south facing so they get enough light, and we have warm/hot summers here, so they get the bake. It can get warm in the greenhouse i.e. 15 Celcius on some days, but I keep it heated between 3-8 Celcius. I wonder if perhaps it could be the higher temperature?

[Luc Gilgemyn]

I'm not a specialist, but I do grow some Onco and Juno Iris.
Difficult to determine what makes them flower or not - I think they do like some cold in Winter, which as I understand it they don't get in your greenhouse. 
With me, some species also skip flowering every now and then for unknown reasons.
I think that sometimes they need to recuperate a year from flowering if conditions have not been ideal for them during their growing season.

[Erika]

Hi Luc,

They do get enough cold in my greenhouse. It's strange. 

[brianw]

Are you feeding them at all? Your growing medium seems to be supplying minerals only.

[Erika]

Yes I feed them biweekly or every 3rd week with 10-52-10 fertilizer.