Usually it will appear like this.
It's not dead yet but it's not living either.
It had seen good days before when the plant is full of beautiful leaves,
robust and filled the pot with bushy leaves but now it is this.
You have done everything according to the rule book of Begonias.
Water only when it is required - no over-watering.
Kept in bright shaded area - no direct hot sun.
All was looking good but after about a couple of weeks,
you started noticing the leaves started to mature and falling off
but there was new growth and so you thought there was nothing to be worried about.
And so, you bought again, this time you tried differently.
You gave more attention to it. Cared for it like a baby and it did so well.
You didn't allow any water from touching the leaves and carefully water the medium only. It lasted longer but it still succumbed and died.
So What Went Wrong?
Let me explain:
Most, if not all begonias are actually brought from Cameron Highlands
and they were planted in coco-peat.
In that highland condition,
where they receive high humidity & they were never watered heavily
(perhaps mist lightly)
And so the begonia had accustomed to the climate and the medium used for growth.
What happens is that when these begonias are brought to low-land climate
where it is very hot and exposed to harsh climate.
Even during the transiting time where it is exposed to low humidity and rough handling.
After the initial shock, the plant now get suffocated due to the condition it is now.
Coco-peat medium tends to get compressed and hardened
when it is watered heavy in lowland hot climate.
And so, the roots suffocate like the medium had choked all the moisture from in between them.
This process normally takes few weeks to months
and the dying process takes place progressively.
You will find that even-though they are heavily soaked and watered
the plant had gone to major stress and had started to shut down.
Most Rex Begonia are Rhizome types and so - it will start to appear going into dormancy.
The worse case scenario is when the Begonia is facing Root Rot.
The fungus / bacteria attack makes it more difficult and no chance for the plant to survive or recover. In most cases - it will die.
So How Do I save my Begonia from Dying?
The Step is To Take Precaution Before The Plant Dies.
1) Always take cuttings and propagate the Begonia for Spare.
Either using Leaf Propagation or Rhizome Propagation.
2) Begonia is not Perennial
These plants may live for few years but they will die due to old-age,
root rot, fungus attack or any other factors.
The best thing to do is plant spares, just in case - the mother plant dies.
What should I do Now?
you are in a current situation now and you are out of options on what to do?
Please click into this link below
for Step by Step detail on What to Do:
3) Saving My Begonia Using Rhizome
4) Saving My Begonia Using Leaf Propagation
Please note, that once the Root Rot or Stem Rot sets in,
the chances of survival is very very low.
So do consider the factor to safe the plant before it dies by propagating spares.
Begonias are actually sensitive plants - they are not hardy.
Another most important factor I noticed is the type and the Brand of Fertilizer used.
They don't do well without fertilizer either.
And so, it's more of a trial & error of finding
what is best for the plant and what works best for you.
I had used goat manure and suddenly shocked to note that the plant started to have fungus attack, the leaves started to rot and falling off. I had stopped using goat manure every since.
I had also used the conventional red granules type (easily available & cheap)
and it too had caused burns and leaf drop.
As for now, I only use orchid foliar fertilizers.
It may be slightly pricey but it doesn't kill my begonias.