Ornithogalum failure to flower

Nathan Lange plantsman@comcast.net
Mon, 08 Dec 2014 12:45:45 PST

Since most commercially grown Ornithogalum dubium crops likely 
consist of genetically identical individuals, I don't think comparing 
their flowering to genetically heterogenous populations in situ is 
valid in this instance. Significantly less than 100% flowering for a 
commercial O. dubium crop suggests three possibilities.

First, the bulbs may not have yet reached a state of physiological 
maturity following the last vegetative growing cycle even though the 
foliage has already died down (I'm not referring to bulb size here, 
although the bulbs do have to be large enough to flower). For 
example, as is frequently the case, the foliage prematurely died 
because the plants were not adequately cared for after the flowers 
senesced, or perhaps the bulbs were harvested too soon from the soil 
resulting in the bulbs not fully maturing. The temperature during the 
bulb enlargement stage of many species can also affect the 
physiological state of the bulbs at harvest.

Second, the bulbs reached a state of maturity and became fully 
dormant but there might now be a dormancy breaking requirement (not 
necessarily warm temperatures) needed before the bulbs can perceive 
the floral induction stimulus (presumed to be warm temperatures). 
Assuming such a dormancy breaking requirement even exists for this 
species, without meeting this necessary dormancy breaking 
requirement, subsequent warm temperatures will not induce flowering. 
Such a dormancy breaking treatment could be something as simple as a 
period of relatively cooler (not vernalization) or even warmer 
temperatures prior to the warm floral induction period.

Finally, the third possible reason for less than 100% flowering is 
that the warm floral induction stimulus was inadequate. The bulbs 
were mature and dormancy (as defined by the ability to respond to a 
floral stimulus) was broken but subsequent temperatures were not warm 
enough and/or for long enough. In the situation of growing plants in 
pots, not fulfilling all three of these potential requirements could 
easily account for less than 100% flowering.

That being said, Hugh's comments are spot on. Whatever their needs 
for full flowering, the major wholesale growers already have this 
species figured out.


At 10:15 PM 12/7/2014, you wrote:

>In nature, many bulbs practice dormancy. It is a means to reduce losses in
>droughty years.
>San Diego

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