cutting onco seeds - forced germination

Peter Taggart
Sat, 15 Nov 2014 15:17:24 PST
I often think of the smaller /northern oncos, paradoxa, acutiloba,
barnumae..... as akin to Iris attica et al, -small mountain plants with,
relatively speaking, no need for great heat in Summer, but wanting a pause
in growth during winter. At the other extreme Iris gatesii, atropurpurea,
lortettii et  al which want to rest in Summer and prefer to have no pause
in growth in winter. Iris sari, meda etc and the regelio cyclus Iris are
the middle ground. Anything which will upset a pogon Iris will kill an
onco. Paradoxa, iberica and elegantissima are in leaf here too, along with
gatesii, lortettii, kirkwoodii, sari, various paradoxa ssp, acutilobas,
barnumaes, autropurpurea, and others.
With the right amount of moisture  they are all evergreen, but to attempt
to maintain that level of moisture in a hot Summer is risky. The moisture
is good if deep down at the roots, but if it rises to the rhizome while
there is heat, the plant will succumb to bacterial rot. If the foliage is
warm and wet it will get 'rust'.

I have never found the embryo exposed by removal of the aril, except with
rotten seeds. I have cut hundreds of seeds, and as pictured in my pictures
on the thread on the Scottish Rock, the hillum end of the seed needs to be
cut for forced germination, as I was taught it, to work.
Peter (UK)

On 15 November 2014 22:33, penstemon <> wrote:

> I studied the pictures on the SRGC forum before proceeding, but I decided
> against cutting the seeds, because there weren't enough bandages in the
> house. If you take a dental pick and gently pull off the aril, the embryo
> is usually exposed. Sometimes it takes a little more effort, but that's
> usually sufficient.
> I grow all the oncos outdoors in raised beds of sand and gravel. I even
> water them in the summer, if I feel like it. Iris iberica and its ilk are
> summer dormant (no leaves), but Iris paradoxa is practically evergreen.

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