GardenBanter.co.uk - Phyllostachys Bissetii Leaves

Giraffeman wrote:
I recently bought a Phyllostachys Bissetii and have kept it in a
container. It was dried out when I bought it but after watering it was
doing really well and putting up lots more culms and lush green leaves,
however, now it's having many leaves turn yellow and not looking as
good.

Does anyone know why this may be? It's been in the same position since
I bought it 3 months ago.

It could be a lot of different reasons. Look into the following:

1. Natural cycle... Bamboos are evergreen, but they do shed 20 to 30%
of their leaves before winter. I have noticed that when mine do this,
the leaves closest to the main culm die first. So, if this is the
pattern you are seeing, then you have no problem.

2. Too infrequent watering... Especially if the root mass is too large
for the container, it could be drying out too quickly and not getting
enough water.

3. Too much water... Too frequent watering can lead to root rot, which
will eventually show via the above groung health of the plant.

NOTE: A meter to check soil dampness is pretty cheap... on the order of
$5 or $10 for the cheap ones. They work pretty well, but they don't
always give an accurate reading depending on the type of soil and how
well the probe makes contact with the soil... Useful, but confirm the
reading by scratching your finger into the top bit of soil.

4. Lack of nutrition: Now is not a good time to fertilize with
nitrogen, because you don't want to trigger shoots that will not have
enough time to harden off before winter. But the plant may be
starved... If you think this is the case, buy a real low-nitrogen
(relatively high phosphorous and pottasium) fertilizer. Something like
a 3-10-10 or 0-10-10 if you can find it. Just a touch should be enough
if this is the case.

5. Over-fertilization: Too much fertilizer (especially high nitrogen)
can burn the roots and show above ground with poor health.

6. The plant has out-grown the pot: This can actually be the main cause
of #2 or #4 above... Container bamboos will grow to displace so much
soil that there is nothing left to retain water and not enough soil for
the roots to pull nutrition from. In this case, you just have to divide
the plant.

Dividing this time of year must not be bad (perhaps if you have a
greenhouse?) because half of the nursery bamboos I have bought had tags
indicating they were divided in Nov. or Dec.

Anyway, it is best to take the plant out and wash off much of the soil
so you can see what you are working with.. Keep it always wet while
doing this, even sticking the parts in a 5 gallon bucket of water while
you are working other parts of the plant if you have to... Letting it
dry out is a really bad thing for the plant.

When dividing, try to cut it into multiple good sized chunks with the
culms attached. You can trim any matted bunched up roots off and
discard them, but try to keep as much healthy root mass attached as
possible. Put each part in a pot that is several inches larger around
than the division you are planting. Use a really loose soil that has
about 30% small bark chips mixed in, and shake the soil down all around
the roots. Don't compress it, but also try not to leave any big air
pockets, such as might be created by a root preventing the soil from
settling down.

Finally, trim the culms down a bit in height. This reduces the chance
that the loose plant will fall over, and also helps balence the smaller
root mass to the amount of leaf mass. If there is only a small section
of rhyzome in the division, trim the top down to where there are only
one or two branches. If there is a good amount of rhyzome and root
intact, you might get away with trimming very little or not at all.

Water thoroughly and if possible, add some B vitamines to the water
(Nurseries sell a transplant mix that includes this).

Good luck!