Chris Hogg wrote:

snips ...
I have P. alata, P. molissima, P. vitifolia, P. 'quadrangularis' as it
is popularly called (most probably P. x decaisneana) and P.
antioquiensis growing in an older-style SW facing conservatory that I
keep at about 10C in the winter months with a small fan heater. It
needs heavy shading in the summer otherwise it gets much too hot, and
the P. antioquiensis shrivels in direct sunshine. Both it and P.
molissima are high-altitude species, and don't like it too hot. It
inhibits the flowering of the latter until the cooler autumn and
winter months (it's been sporadically flowering all winter). P.
antioquiensis hasn't flowered yet. I used to have P. x Incense but
space is limited and I prefer the larger and brighter flowered
species!

I grow them in large planters and troughs, as they like plenty of root
space. I use John Innes Ericaceous compost, with about 25% extra grit
or grit-sand added to improve drainage. They need to be kept well
watered, especially in the summer, usually twice a week, but check the
soil moisture before you do it. I feed every three weeks or so with
ericaceous fertiliser at the recommended strength.

With the exception of P. antioquiensis, I've had then all about four
years. They flowered well in the first two years, but since then
flowers have got fewer and leaves smaller. I shall re-pot them this
spring, and probably cut them back fairly hard. They don't seem to
mind, provided you leave two or three feet of stem for re-growth. The
roots will also get trimmed.

My P. molissima suffers badly from red spider mite and it had thrips
last year. But the big-leaved P. alata and P. quadrangularis haven't
suffered from either yet; perhaps the leaves are too tough. I treat
both with natural predators, as RSM in particular is resistant to most
insecticides, and once you've introduced the RSM predator you can't
use insecticides for any other bugs as you'll kill the predator.

If you want a good book on passifloras, I recommend 'Passion Flowers'
by John Vanderplank, the MIT press.

Thank you - useful information.
--
Larry Stoter