Timing for bulbs changing hemisphere?

Paul Tyerman ptyerman@ozemail.com.au
Fri, 11 May 2007 15:19:21 PDT
Howdy All,

It has been brought to my attention that my last emails were blank to 
the list....... here's a resend.



Thanks for the response (well it was in response to Lee, but was 
still a help to me! <grin>)  I am interested in input from anyone on 
this, as everyones experiences differ.  If I could ask a couple of 
questions of you?...

>Their first physiological requirement after dormancy is the warm dry
>period - when they are completely dormant. We in the UK were then going into
>autumn with falling temperatures. To pot them then and place them in
>ordinary greenhouse conditions would not give them this and cool dampness
>would probably cause rapid rotting of the bulbs.

This was one of the reasons I was asking about the whole shifting 
straight after dormancy thing.  Would it actually be better for me to 
leave the bulbs a couple of months after they go into dormancy (i.e 
half way into summer, but still long before they would naturally be 
activating again) and then send them to people in the North? That way 
they would get a half dormancy here, then start into growth on their 
arrival in the colder climes up in the north.  I figure then a short 
growing season and normal dormancy would put them into sync with the 
northern hemisphere?  I have often wondered if this is the way to go 
or not, as it gives them a short summer here before sending them.  I 
know if I leave it until late in summer they I have had failures in 
the past, but I also haven't left it late enough that they were just 
starting to activate growth as I sent them.  I am still wondering 
whether this is viable or not, as they then have their short growth 
season and then go dormant again?

>I could have opted to try a spring planting but a) there would not have been
>a long cooling down period to get the bulbs active and growth would have
>been curtailed by rising temperatures in early summer (although the hot dry
>dormant period would have ensued, enabling growth to restart in autumn as
>temperatures drop.)

This is where I am wondering whether bulbs conditioned for my climate 
would regard the rising temperatures in many of the colder areas as 
warm enough to be summer, and so they would grow for a bit longer as 
they are expecting it to be hotter?  Am I correct in assuming that 
they will have acclimated to my hotter summer by perhaps growing into 
slightly higher temperatures than they would normally continue in up north?

>In keeping such bulbs dormant over extended periods it is esssential that
>they do not desiccate, so they must be packed in some insulating material
>(vermiculite or sand, etc) to prevent this.

This one is just so important isn't it!!  The poor bulbs that are 
forced to sit through an extra 6 months of dormancy have to use their 
internal reserves to keep themselves alive for that long.  Even 
though they are dormant they're still keeping themselves alive 
throughout that time, not just in a complete suspended animation that 
can last forever. <grin>

Thanks again for the email.


Paul Tyerman
Canberra, Australia - USDA Zone Equivalent approx. 8/9

Growing an eclectic collection of plants from all over the world 
including Aroids, Crocus, Cyclamen, Erythroniums, Fritillarias, 
Galanthus, Irises, Trilliums (to name but a few) and just about 
anything else that doesn't move!!  

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