David Shepherd wrote:
The plant is in the second year of life, I've only ever given it rainwater
and deionised water. It has plenty of sun, but maybe not much humidity. It
started to grow a flower just before these problems happened. I cut the
flower off after reading that it takes too much energy from the plant.
Hopefully it was the right thing to do.



Given the apparent health of the plant, cutting the flower was probably
for the best. Fowering diverts energy away from vegetative growth. If
the plant is struggling it may not have enough energy to spare. BTW,
flowering is perfectly normal for flytraps. It's generally not a sign
of poor health. Unfortunately flytrap flower cues often take precedence
over ability.
You're obviously doing right with regard to water quality and sunlight.
How much is 'not much humidity'? 60-80% is around optimal but mine are
outside and get down to 30-40% in summer without much set back so long
as the water is kept up to them.
A few questions:
How big is the pot?
4"-6" pots are suitable (or bigger if you want). The 2" pots are OK for
seedlings etc but they do restrict root growth and if you're watering
by sitting the pot in a tray of water (as is usually recommended) it
can stay a little too wet. With pots over 4" you can sit the pot in an
inch of water the plant will still have enough root space above the
water level.

When was the last time it was repotted?
Peatmoss + sand mixes are most common for these plants. Unfortunately,
wet peat (which flytraps like to grow in) sours easily. Replacing the
mix every two years is recommended. It might be a little late in the
season to disturb the roots and repot yours. Repotting in winter/early
spring is recommended (ie when it's dormant). You may be able to buy
time until then by 'potting up' the plant into a larger pot using fresh
peat mix (2 peatmoss: 1 sand) around the undisturbed rootball.

Did you let it go dormant?
Flytraps are native to southern North Carolina crossing over into the
northern part of South Carolina. ie they are temperate plants and need
a cool winter dormancy. ~Zone 8-10 winter minimums will probably give
the best rest period. If you're in a subtropical/tropical area or
growing them indoors (windowsill/terrarium) you will need to find a way
of providing them with a ~3 month cool dormancy period.

If you really want to succeed with these plants, I'd suggest you do
yourself a huge favour and track down The Savage Garden by Peter
D'amato. It's reasonably priced (I think it's still in print), and
gives a fairly thorough coverage of how to grow flaytraps and most
other carnivorous plant genera. The writer is an accomplished grower of
carnivorous plants so the info is reliable. To be honest, you've got
the most important requirement (low ppm water) under control. With a
bit of fine tuning in your culture you'll soon realise that flytraps
are dead easy to grow.

Good luck,
Andrew