Oncoseason 2010

[Hendrik Van Bogaert]

wonderfull Hendrick !

and very nice foliage too with some crocus background    ??
I'm waiting for a new one when completly open....

Thank you for your lovely comments.
Indeed Fred, in the background stay a pot of Crocus biflorus ssp. nubigena; you can see pictures of it on the Crocus pages.
Best wishes
Hendrik

[Hans A.]

Superb Plant, Hendrik!
The early flower also surprises me a bit, - it is one of the last to flower here, normally in April. 

[Hendrik Van Bogaert]

Hi Hans,

It's the first year that I have flowers. I have no explication for this early flowering.

Hendrik

[Hans A.]

Hendrik,
the early flowering of your Iris acutiloba might caused in your avanced Lightsystem which could induce the plant to flower earlier than in natural conditions. Your experience with Iris sprengerii points in this direction.
When plants are very well feeded they sometimes tend to flower to death, especially fertilizer with high concentration of phosphorus seem to be dangerous.  Hardly existing (leafy) stalks could indicate this.
Once I grew an Iris paradoxa which started to flower in November and did not stop  until summer - it was to much for this plant and it did not appear again after going dormant. (There is somewhere in this forum a similar report about one plant of Iris afghanica). 
Now I feed very carefully and if a single plant has more than ten flowers i become a bit nervous, but fortunately I had lost any of those.

[arillady]

Hendrik,
Superb photos of a wonderful species. Well done.

[jomowi]

Hans, in my days studying plant nutrition, Phosphate toxicity is a well known and researched problem

[Hans A.]

Thanks Brian,
my knowledge about plant nutrition is only very basic. So please feel free to correct me if I am wrong.

Common fertilizer often used for Oncos are those for tomato or even cacti, with relativ low quantity in nitrogen but high in Phosphate and Potassium. This works fine if you grow them on a sandy soil.
On heavy clay (as in my old garden) phosphate remains very stable so fertilisation has to be much more carefully if it is not completly superfluous for those plants. Maybe a Phosphatefree fertilizer would be helpful.

[Hendrik Van Bogaert]

Hendrik,
the early flowering of your Iris acutiloba might caused in your avanced Lightsystem which could induce the plant to flower earlier than in natural conditions. Your experience with Iris sprengerii points in this direction.
When plants are very well feeded they sometimes tend to flower to death, especially fertilizer with high concentration of phosphorus seem to be dangerous.  Hardly existing (leafy) stalks could indicate this.
Once I grew an Iris paradoxa which started to flower in November and did not stop  until summer - it was to much for this plant and it did not appear again after going dormant. (There is somewhere in this forum a similar report about one plant of Iris afghanica). 
Now I feed very carefully and if a single plant has more than ten flowers i become a bit nervous, but fortunately I had lost any of those.

Hans,
The light system could be the reason, but in 2009 I didn't use the Led's and my Iris sprengeri was earlier than this year.
I think that my onco's will always be earlier in Belgium than in other countries; are autumns are relatively warm en humid; even without water gift my onco's emerge already in september...this due the high air humidity. Belgium is not a land for growing such plants, but I can't resist it...
Hendrik

[Hans A.]

Belgium is not a land for growing such plants, but I can't resist it...

I am not so sure about that  
Many Oncos bloomed here in the past years - but of Iris sprengeri, which is one of my oldest plant I grow never got a flower. It is as other 'northern' species tricky here.

[Oron Peri]

At least 4 weeks earlier this year, Iris petrana in flower.
I grow vary few Oncos. since my garden is too shady and humid for them but some how this one insists on growing...
This form is also known as I. hieruchamensis,
 this name is still used here but apart of blooming a bit earlier and having slightly thinner leaves there is no difference between the two population in the Negev desert and in Jordan.

[Maggi Young]

Ooooh......

[David Nicholson]

.... and me

[Hans A.]

Great plant Oron!
Perhaps you should not work so much, so you could take the pictures in normal daylight.
The Israelian petranas seem to vary more in the colour than those of Jordan, which are said to be quite uniformly dark.
Just for comparision some last year pics of an Iris petrana which should come from Jordan - with backlight the flowers get a reddish tone.

[BULBISSIME]

Oron, 4 weeks earlier in your garden... the same in nature  
Very nice pic,... and I like the light 

[Hendrik Van Bogaert]

Great plant Oron!
Perhaps you should not work so much, so you could take the pictures in normal daylight.
The Israelian petranas seem to vary more in the colour than those of Jordan, which are said to be quite uniformly dark.
Just for comparision some last year pics of an Iris petrana which should come from Jordan - with backlight the flowers get a reddish tone.

Hans, Oron,
Wonderful plants!
Thank you.
There is something I don't understand. Iris petrana grows in Israel in sandy soils at low altitude; the plants I found in the surroundings of Petra (Jordan) were growing at heigh altitude (1500 m) in heavy soil, between calcareous rocks.
Are they the same species?
Hendrik