Tropaeolum tricolor, was Mystery bulb identification

Jane McGary
Fri, 16 Feb 2018 08:47:05 PST
Tropaeolum tricolor is one of the hardier species in its genus, able to 
survive ambient temperatures in the 20s F but not much lower, in my 
experience. I lost my old plants after training them on metal supports 
inside the bulb house; the metal apparently exacerbated freezing 
temperature around 18 degrees F, and the upper parts of the tubers 
rotted. However, one of them had leapt to the wire mesh side of the bulb 
house and flowered outside, where hummingbirds pollinated it (these are 
the natural pollinators), so I have a few self-sown seedlings now that 
are about flowering size. I hope they survive the 23 degrees F predicted 
for next week.

Tropaeolum speciosum is usually considered the hardiest species (it 
comes from a climate similar to that of the coastal Pacific Northwest), 
but Tropaeolum brachyceras, which someone mentioned is in flower in a 
greenhouse now, is also pretty tough. There are alpine species, but in 
nature they're protected under snow in winter and emerge in spring. I 
also grow Tropaeolum azureum (and may lose it next week as it's now too 
tall to cover, but you never know). All the ones I've grown except T. 
speciosum do well with a dry summer dormancy.

Tropaeolums form large seeds and you have to watch them closely in order 
to harvest them before they drop off and are carried away by ants.

Jane McGary
Portland, oregon, USA
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