Last season I planted a potato vine because I loved the purple flowers
it promised to provide. Well, it got HUGE trellised to the fence,
shooting up 10 feet to resemble a tree, but never put out a single
flower. I can only hope that it'll put on a better display this
season. I'm wondering whether cutting it back might stimulate some
flower production, or whether it'd be advisable in any case. And if
so, how far back should it be pruned?

In article ,
(Fleemo) wrote:

Last season I planted a potato vine because I loved the purple flowers
it promised to provide. Well, it got HUGE trellised to the fence,
shooting up 10 feet to resemble a tree, but never put out a single
flower. I can only hope that it'll put on a better display this
season. I'm wondering whether cutting it back might stimulate some
flower production, or whether it'd be advisable in any case. And if
so, how far back should it be pruned?

I presume this is the evergreen Blue Potato Vine (Solanum crispum
glasnerium). If trellised it should be pruned close to the trellis every
spring or late winter (or even at the end of summer), or it will just
spread further & further away from the wall. It recovers rapidly from even
the heaviest pruning, but don't overdo it, just do what is necessary to
keep it more on than off the trellis, with attractive form. Be careful to
preserve a couple of main woody vines that can thicken up to actual trunks
over time, & take care that you've arranged the main saved sections so as
not to push the trellis forward as vines turn to limbs & trunk. (When mine
is much bigger I plan to let it bush as far away from the top of the
trellis as it wants to reach, so it'll be like a big shrub on top of a
trellised vine with only the lower portion kept pruned to the wall, but
right now I'm trying to keep it all somewhat flat to the trellis.)

I'm not sure if by "last season" you mean last spring, but if so, I'm
surprised it produced no flowers; if you planted it late it may have
decided to stop blooming for a while & work on its roots & leaves. A
pruning about now SHOULD induce it to flower very greatly beginning no
later than May, though I've found it flowers no matter what. A light
dosing of nitrogen right now might give it a burst, though sometimes
fertilizing just increases leaf growth & rangy vining growth on some sorts
of vines, so that might not be the answer. It needs plenty of sun, so if
yours is much shaded, that might be the problem, though mine happens to be
thriving with all-morning sun only.

I began with a small start; it tripled in height in no time & bloomed
continuously deep into autumn with no attention at all, & presently is
again full of new green buds, preparing to start anew. It even provided a
scant handful of flowers out of season during the winter, just one
unexpected spot of blue now & then (this past winter was unusually mild).
Perhaps yours experienced some terrible stress in its pot before you got
it & took this while to establish roots &amp height, so will this year
bloom as well as it is expected to. I've not heard of them being
unreliable for bloom, I've only heard some people complaining they don't
make it through their first winter in zone 8 or below (while others
including me, knock wood, detect no winter stress at all in zone 8).

Last year I gave it a webpage:
http://www.paghat.com/bluepotatovine.html

-paghat the ratgirl

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
See the Garden of Paghat the Ratgirl: http://www.paghat.com/