Tropaeolum notes
Jane McGary (Wed, 08 May 2013 11:16:39 PDT)

The flowering season of the small Tropaeolum species I grow is coming
to an end. I had never obtained seed from Tropaeolum tricolor before,
but this year one of the plants found its way to the outside of the
bulb house and climbed up the wire mesh that forms the side panel,
where hummingbirds had access to it. Many seed capsules are forming
on the outside flowers, and none on those inside the house.
Apparently only birds can pollinate this species. In contrast,
Tropaeolum brachyceras has yellow flowers that are flatter in form,
and I saw bumblebees on these, both inside and outside the bulb
house. It has frequently formed seeds, and most of the plants I have
now are volunteer seedlings from my original one grown from Watson's
collection. Bumblebees must also have come to Tropaeolum hookerianum
subsp. austropurpureum, because it's ripening seed for the first
time, having been grown from a Watson collection in the late 1990s.
It will be interesting to see if the offspring show signs of
hybridization with the similar T. brachyceras; I hope not, because
the purple-flowered species is pretty and uncommon in cultivation.

I hope someday to obtain some of the larger, montane Tropaeolum
species. Tropaeolum incisum came up from a discarded seed in the bulb
frame at my former home, but I couldn't find the tuber though I dug
around for it quite a bit. It may have plunged very deep. I bade
goodbye to the little emerging plant the other day, having finally
sold the house. The tropaeolum has survived three years without
overhead protection.

Jane McGary
Portland, Oregon, USA