I'm assuming you're talking about a semi-epiphyte, the kind with flat,
triangular, or even round stems. They may or may not have visible spines but
all will grow arial roots along their stems especially when stressed for
water. This is the most common kind I've come across referred to as night
blooming cereus. They may include Hylocereus, Selenocereus, Epiphyllums,
etc. Regardless of the name, they all want a porous, well-drained, but
moisture retentive mix to grow in. We grow the epiphyllums in a mix of
spongerock and coconut chips with a healthy handful of coconut dust thrown
in each 12" basket. The uprights or rampant growers we pot in 4-5 gal
containers of similiar mix and try to keep them from rooting through the
woven ground cloth into the ground. Pot-bound is not a problem. When their
happy, your main job will be to constrain their growth. We had a Hylocereus
we struggled to keep at 6-8'. We treat them similiar to our orchids by
fertilizing them 1/2 strength every week with bloom builder substituted in
early spring. With strong light ~50% shade, ours bloom over several weeks
with as many as 20 blooms open at a time. There's frequently a rebloom in
late summer.
Now if you are talking about a Cereus peruvianus or similiar relative,
potting in a well-drained mix is still a requirment. Run a large knife
around the inside of the pot right up against the pot to remove the roots
from clinging to the pot. Disturb the roots if they're a tight mass so there
are free ends to grow out into the new mix and repot in the next larger pot.
I don't know many who refer to this as the night blooming cereus, although
the flower is large, opening at night at lasting several days.
I do believe, however, that a person can grow a plant well by its common
name without knowing the technical one. People have done it for many years,
and without ridicule.
"gwayner" wrote in message
...
I have a night blooming Cereus that bloomed about 20 years ago and never
since. What do I have to do to get it to bloom again.