[Arisaema-l] Arum Seed

[www.rareplants.de]

David,

in addition to Ellen's excellent recommendations: strictly Mediterranean 
Arum pictum pictum, Arum pictum sagittifolium, Arum hygrophilum, and to 
a lesser extent Arum italicum will readily germinate throughout the 
year, if pots are kept at around 20°C/67°F. If sowed at these 
temperatures in spring  and kept in a cool and fresh spot during summer 
(partial shade), they tend not to go dormant in summer, but to keep 
their first leaf till autumn and then to make their second and probably 
third leaf during autumn and winter. This way tubers are significantly 
larger than those which are sowed at higher temperatures and thus will 
not germinate till autumn.

More continental species (e.g. Arum maculatum) will require a cooling 
period prior germination. They will not germinate if seeds are not 
exposed to cool temperatures for several weeks/months. Pots should be 
placed in a protected spot outside during winter, where soil may not 
freeze through. A perfect spot would be in a cold frame and pots sunk 
into the soil. A touch of freezing on the top is ok, but seeds 
themselves should never be deep-frozen.

Cheerio

Bjørn