Cardio. giganteum
Thu, 25 Apr 2013 05:09:15 PDT
Todd we grow all the Cardio taxa here and the approach is the same for each one as adopted here at any rate.

Whether in the ground or in pots, lift the mother bulb, or what is left of it, gently separate off each bulb offset, there may be several at different stages / ages of development. Plant them up individually, perhaps in a nursery holding area or long tom type pots but keep away from direct sunlight prior to final intended position[s]. 
I have never heard of or known a mature bulb to flower more than once but cannot categorically say that it doesn't happen but I suspect what you observed was a daughter bulb doing so subsequently.

We find if the bulbs are not individually disjoined then they become very congested which can both inhibit or delay subsequent flowerings, also the quality + number of blooms per stem are greatly reduced. As I am sure you know Cardios, whatever taxon are gross feeders, also bulbs should only be planted with their 'noses' just about at ground surface level. Due to extremer winter temperatures our Cardios have a deep layer of leaf litter pilled on top in the Autumn with a light sprinkling of sand / soil on top to stop it blowing away. Snow is also piled on top too as this adds to the insulation effect and has allowed us to take all taxa through temps as low as - 26 C. Regular and adequate watering is essential following onset of growth and given our short growing season at this latitude I and others 'cheat' by providing a liquid feed, initially high in Nitrogen, say 20:12:10 or similar, then dropping down to 12:10:10 or similar. This ensures good flowering at the end and helpin
 g to bulk up offset bulbs early on as they obviously are competing for both moisture and nutrients if still bunched up with each other.

Flowering, across the species, is as far as experience here goes, always best from seed originated bulbs, from offsets less so but 8-10 years from seed is enough to test any gardener's patience and settling for offset bulbs at c. 4-5 years is a liveable second best. Being avaricious I flog both horses, the scent is quite something and noticeable from upto 100 metres of an evening. Go for it and enjoy. Iain

More information about the pbs mailing list