Tropaeolum polyphyllum hardiness

Rodger Whitlock
Fri, 09 May 2003 21:49:25 PDT
Alberto Castillo wrote regarding Tropaeolum species:

> Polyphyllum, incissum, and sessilifolium spend their winter
> dormancy very dry under show. The zone would be U. S. 8, always
> growing in a scree.

Ten to fifteen years ago I bought a pot of T. polyphyllum and 
unwittingly planted it out in the open garden. My soil is quite 
heavy, and I am a low spot, so winter conditions involve standing 
water after heavy rains. Far from being scree conditions!

The plant survived and is alive to this day, having gradually crept
from the original site to a position under a nearby raised patio, a
distance of perhaps a meter. This new site seems to agree with it
very well: as long as it gets adequate sun (i.e. as long as I hack
back the buddleia that threatens to take over), it flowers
modestly, though not as luxuriantly as specimens I have seen in more 
suitable condition. I have even had viable seed off it, and am 
growing on seedlings in a large pot. They themselves may flower this 

I should add that my concrete patio is very old, has settled a great 
deal, and has large cracks in it; the tropaeolum comes up in the 
crack between the concrete slab and the low supporting wall.

Although not a bulb, Nierembergia rivularis is worth mentioning in 
this context. I have it in the cracks in the patio, and it does 
extremely well there, flowering profusely for a long period in the 
summer. It seems that sites under a concrete slab provide some 
combination of temperature and moisture that agrees well with some 
otherwise tricky plants.

Rodger Whitlock
Victoria, British Columbia, Canada
"To co-work is human,
to cow-ork, bovine."

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