Re: CULT: roots
iris@hort.net
  • Subject: Re: CULT: roots
  • From: L* M* <l*@lock-net.com>
  • Date: Sun, 21 Nov 2010 06:03:35 -0500
Interesting. I see a lot of variation in rate of root growth in newly planted rhizomes here, especially some of the Oz/CA and even OR bred ones, so it may be some of the same effect you are seeing. I had never thought of it being temperature related.
I can't take the heat, and definitely can't provide adequate care for newly planted rhizomes in hot weather. So I'm usually not ready to plant, even in pots, sitting in the shade, until September, even later this year. After most places have quit shipping. So even if I have to purchase in August, they usually sit in a bag or box till cooler weather.
I just checked yesterday and potting temperature was between 45 & 50oF at the end of the day, regularly getting cold enough to frost, but no really hard freezes so far. 11 out of 23 new arrivals had not grown roots out the bottom of their 1 gallon pots a week before, but I found roots coming out the bottom of one of those 11 yesterday. And two of the 11 are a very late order from Schreiners, not planted till mid October, so they may make it yet.
So that leaves 8 with not much root growth to speak of, 7 are GBK (Ghio, Blyth, Keppel). If it's a temperature effect, that would also explain why rhizomes shipped all the way from Oz, planted in spring, seem to establish better than those planted in fall.
And it also may help explain why covering all the storeboughts over the winter with floating row covers has given much better survival & spring bloom. I've assumed it was just because it was protecting from all the up and down temperatures, but it also does keep things generally a bit warmer. And our warmer winters may also help.
Interesting that they won't grow roots in the relative cold of your winter, but will bloom! crazy plants. 


I have set out iris rhizomes in September when
the temperature was 108 degrees and they grew rapidly and bloomed well in
the spring, while my late, cool replantings did poorly.  Perhaps that is
another characteristic of my hot bred irises.  They can take more heat than
I can now days.
I see no sign of rebloom on anything yet.

Francelle Edwards  Glendale, AZ  Zone 9


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