HI All
A nice parcel of 'common' and 'exotic' tubers arrive in the post today
(common = fresias & achimenes, exotic to me, at least being Gloriosa
and Sandersonia).

The last two warned against 'overpotting'.
At the risk of asking a silly question - I'm guessing that this means
'don't put them in too big a pot'...
..... am i correct ??

The gloriosa, in particular, is a very strange-looking beast - being a
long tuber, a bit like a very long, fat potato chip - and it was quite
a challenge to find a suitable container to sit it in and fit into the
propogator. Finally ended up with a fruit-juice carton with one side
cut out and drainage holes added, laid on its side....

Now, when the thing bursts into life, I'm not sure how I can get it
into a suitably large pot without 'over-potting' it....

Maybe I can 'cheat', as you might with chitted potatoes, and cut the
tuber in half - ending up with two 3" tubers rather than one 6"
tuber....

Any thoughts please ??

Having to resort to 'indoor gardening' as we've got one of those 'soft
Irish days' out here today - visibility just about as far as the
garden gate, if you're lucky g

Thanks
Adrian

Adrian wrote:

The gloriosa, in particular, is a very strange-looking beast - being a
long tuber, a bit like a very long, fat potato chip...

Adrian this is far easier to do than explain, so don't hesitate to ask
for clarification if necessary. Anyway here goes...

Every year Gloriosa produces a new set of tubers, the old ones
shrivelling away as they nourish the growing shoots. Unlike many
tubers, Gloriosa has its growth buds concentrated at the tip and not
scattered along the length. Normally, they are paired rather like a
two-pronged fork and joined at the base of the previous year's shoot.
If these the apical buds (those at the tip of the tuber) are damaged
then the entire tuber usually dies.

It's not a good idea to cut the tuber into sections since latent buds
rarely form along its length and you are effectively reducing the
amount of nourishment that will be available for the new shoots. In
the Gloriosa world, the longer and fatter the tuber, the stronger the
new growth, which will produce more flowers over a longer period.

As you've found, these tubers are very difficult to accommodate.
Planting them horizontally means that you need a much wider pot than
is necessary. They should be planted vertically at an angle in a deep
pot with the cut or broken end of the tuber uppermost at the edge of
the pot. The 'active' tip should be towards the centre and several
cms. deeper. This reduces the need for such a wide pot.

When I grow Gloriosas, I dont try to bury the entire tuber and allow
the first few cms.of the cut end to remain above compost surface.
Also, if the tuber is relatively short, it can be planted vertically
in a sweet pea tube and once growth is well under way, the lot then
transferred to a bigger container. Larger tubers are probably better
started in home-made (non-plasticised) cardboard tubes about 10cms.in
diameter and 20 - 25cms. deep. These are then easily transferred to
large pots at a later stage. The cardboard degrades naturally and
roots will grow through it..

Gloriosa tubers are very prone to rotting if the compost is kept too
wet, hence the advice to avoid 'overpotting'. It is very important
that the compost is free-draining and the addition of 1 part
horticultural grit/sand to 4 parts compost ( a good quality, not cheap
multi-purpose is OK) is ideal. Water well and then allow the compost
to nearly dry out between waterings. When the new shoot appears, you
can gradually increase the frequency of watering, but never allow the
compost to remain sopping wet. Once the new shoot is about 12 -
15cms high, you can repot into 25-30cm diameter container and it is
best to insert support canes at this stage rather than risk damaging
the roots later.

After a few weeks you should start to apply a general purpose liquid
fertiliser at 10 - 14 day intervals. This will promote strong growth
and encourage the formation of flower buds. When flowering has
finished, continue feeding and watering until the leaves start to
yellow. It is during this time that the new tubers are being formed
to provide next year's plants so they need a bit of encouragement.
Gradually reduce watering until the top growth has completely
yellowed. Overwinter dry in a frost free place and then carefully
remove the new tubers from the compost in early spring. This time you
will have a pair, which you can either split or keep together. Just
make sure you don't damage the ends.

HI Dave

Firstly - many thanks for the reply.....

On 27 Feb 2007 00:59:28 -0800, "Dave Poole"
wrote:

Adrian wrote:

The gloriosa, in particular, is a very strange-looking beast - being a
long tuber, a bit like a very long, fat potato chip...

Adrian this is far easier to do than explain, so don't hesitate to ask
for clarification if necessary. Anyway here goes...

Every year Gloriosa produces a new set of tubers, the old ones
shrivelling away as they nourish the growing shoots. Unlike many
tubers, Gloriosa has its growth buds concentrated at the tip and not
scattered along the length. Normally, they are paired rather like a
two-pronged fork and joined at the base of the previous year's shoot.
If these the apical buds (those at the tip of the tuber) are damaged
then the entire tuber usually dies.

OK


It's not a good idea to cut the tuber into sections since latent buds
rarely form along its length and you are effectively reducing the
amount of nourishment that will be available for the new shoots. In
the Gloriosa world, the longer and fatter the tuber, the stronger the
new growth, which will produce more flowers over a longer period.

Also OK - it was just a thought ! g


As you've found, these tubers are very difficult to accommodate.

That's what prompted me to 'ask the audience'..

Planting them horizontally means that you need a much wider pot than
is necessary. They should be planted vertically at an angle in a deep
pot with the cut or broken end of the tuber uppermost at the edge of
the pot. The 'active' tip should be towards the centre and several
cms. deeper. This reduces the need for such a wide pot.

Right....
The instructions mentioned the need for maintaing a temperature of 25c
in order to break the dormancy - about the only place I can do that
(reliably) is in my propagator - which is designed for seed-trays - so
has limited headroom. Do you think that my juice carton will do the
trick, at least until the tuber starts sprouting ?? If not, I'll have
to work on a 'Plan B'....

When I grow Gloriosas, I dont try to bury the entire tuber and allow
the first few cms.of the cut end to remain above compost surface.

I must reexamine the tuber - I didn't notice a cut end.....

Also, if the tuber is relatively short, it can be planted vertically
in a sweet pea tube and once growth is well under way, the lot then
transferred to a bigger container. Larger tubers are probably better
started in home-made (non-plasticised) cardboard tubes about 10cms.in
diameter and 20 - 25cms. deep.

Hmm - I could certainly make one of these - but then there's the
question of where to put it for the necessary warmth (no sarky
suggestions anybody !)

These are then easily transferred to
large pots at a later stage. The cardboard degrades naturally and
roots will grow through it..

Sounds like a good plan...


Gloriosa tubers are very prone to rotting if the compost is kept too
wet, hence the advice to avoid 'overpotting'.

Not sure I understand the term (......still - bit slow on the uptake
this morning !)

It is very important
that the compost is free-draining and the addition of 1 part
horticultural grit/sand to 4 parts compost ( a good quality, not cheap
multi-purpose is OK) is ideal.

OK - currently the tuber is in about 25% vermiculite and the rest is a
'bog-standard' peat compost. I do have a quantity of peat-free compost
- would you think that would be better ??
Don't have any hort. sand..... but I'm sure I can get some...

Water well and then allow the compost
to nearly dry out between waterings. When the new shoot appears, you
can gradually increase the frequency of watering, but never allow the
compost to remain sopping wet. Once the new shoot is about 12 -
15cms high, you can repot into 25-30cm diameter container and it is
best to insert support canes at this stage rather than risk damaging
the roots later.


OK - that all makes good sense...

After a few weeks you should start to apply a general purpose liquid
fertiliser at 10 - 14 day intervals. This will promote strong growth
and encourage the formation of flower buds. When flowering has
finished, continue feeding and watering until the leaves start to
yellow. It is during this time that the new tubers are being formed
to provide next year's plants so they need a bit of encouragement.
Gradually reduce watering until the top growth has completely
yellowed. Overwinter dry in a frost free place and then carefully
remove the new tubers from the compost in early spring. This time you
will have a pair, which you can either split or keep together. Just
make sure you don't damage the ends.

Right.....
a bit more complicated than hyacinths, then ?? g
Same principles, I suppose....

I also have a Chinese Lantern Lilly (Sandersonia aurantiaca) tuber -
which looks broadly the same as the Gloriosa - but on a much smaller
scale - and has two 'branches' joined together in a bulb-like thing.

Any special suggestions for 'which way up' on this one ??

The funny thing is, many many years ago I successfully raised Gloriosa
from seed (using the simplest of equipment and 'not knowing it was
difficult') This year I've tried again, armed with propagator and
another 20 years experience - and I've ended up with four tiny (really
tiny !) seedlings, which I've potted on more in hope than
confidence...

Guess there's a life lesson there somewhere !

Many thanks for the info Dave - I'll report back when the
sun-room is a mass of vines & flowers with small tropical birds
nesting g

Adrian
West Cork, Ireland

Adrian wrote:

Right....
The instructions mentioned the need for maintaing a temperature of 25c
in order to break the dormancy - about the only place I can do that
(reliably) is in my propagator - which is designed for seed-trays - so
has limited headroom. Do you think that my juice carton will do the
trick, at least until the tuber starts sprouting ?? If not, I'll have
to work on a 'Plan B'....

Well, I would dispute that it needs 25C to start sprouting - 20C is
enough, but it will certainly make a rapid start at those
temperatures. You will need to be extremely careful when transferring
to a pot later - unlike many plants a broken root will not branch, it
will die back completely. If the clear plastic cover is restricting
headroom in your propagator, there's nothing to stop you fashioning a
bigger one using stiffish wire and heavy duty polythene.

... Larger tubers are probably better
started in home-made (non-plasticised) cardboard tubes about 10cms.in
diameter and 20 - 25cms. deep.

Hmm - I could certainly make one of these - but then there's the
question of where to put it for the necessary warmth (no sarky
suggestions anybody !)

A warm windowsill would be enough, just don't let it get too cold at
night especially if you've watered it that day.

Gloriosa tubers are very prone to rotting if the compost is kept too
wet, hence the advice to avoid 'overpotting'.

Not sure I understand the term (......still - bit slow on the uptake
this morning !)

Over-potting means putting them in a pot that is too large in relation
to the size of plant. A small plant with a limited root system cannot
take advantage of a huge volume of compost immediately. The compost
remains too wet for too long, becomes compressed and air-less and
starts to deteriorate, which in turn causes the roots to rot. Plant
roots are stimulated by changing conditions within a pot. As the
compost dries out, they grow in order to 'search' for more moisture.
Keep them growing and you can't go wrong.

OK - currently the tuber is in about 25% vermiculite and the rest is a
'bog-standard' peat compost. I do have a quantity of peat-free compost
- would you think that would be better ??
Don't have any hort. sand..... but I'm sure I can get some...

Well it's a matter of choice. I don't like vermiculite because it
does not improve drainage or aeration in the compost and holds on to
water for too long. Perlite is better - it provides drainage,
aeration and doesn't hold on to excessive amounts of water. I have to
admit that I have never found a truly satisfactory peat-free compost,
but that's a personal thing I can just about live with.

You weren't sure which end was which with your Gloriosa. Generally,
on a fully dormant tuber, the 'active' end will be rounded, fatter and
can be almost toe-like.

I also have a Chinese Lantern Lilly (Sandersonia aurantiaca) tuber -
which looks broadly the same as the Gloriosa - but on a much smaller
scale - and has two 'branches' joined together in a bulb-like thing.

Any special suggestions for 'which way up' on this one ??

This makes things easier... Sandersonia aurantiaca is quite closely
related to Gloriosa and a complete Gloriosa tuber will look vaguely
like a giant version of the Sandersonia, but without a swollen rhizome
in the middle. The uppermost "bulb-like thing" is a swollen rhizome
connecting the tubers, but the growth will arise from the tips of the
tubers. Sort of 'shoulders uppermost, arms down' with the new shoots
developing at the ends of the arms. A bit of a strange analogy, but
I'm sure you'll be able to see what I mean. If you plant upright with
the 'shoulders' just below the surface of the compost the Sandersonia
will be fine.

The same applies to Gloriosa, but because they are quite valuable
suppliers split the tubers and they get at least two for one. A very
well grown plant may produce several tubers and at one time you could
get a complete set for your money, which gave at least two strong
shoots. Not so now

I'll report back when the
sun-room is a mass of vines & flowers with small tropical birds
nesting.

And when you've grown your plant on for a few years with plenty of
tubers to spare, you could try planting one out in a sheltered, sunny
spot in very well drained soil. It can be grown outside in milder
regions (as can Sandersonia and another 'cousin' - Littonia modesta),
but that's another story.

HTH.

HI Dave
Many thanks for the info....

On 28 Feb 2007 00:37:49 -0800, "Dave Poole"
wrote:

Adrian wrote:

Right....
The instructions mentioned the need for maintaing a temperature of 25c
in order to break the dormancy - about the only place I can do that
(reliably) is in my propagator - which is designed for seed-trays - so
has limited headroom. Do you think that my juice carton will do the
trick, at least until the tuber starts sprouting ?? If not, I'll have
to work on a 'Plan B'....

Well, I would dispute that it needs 25C to start sprouting - 20C is
enough, but it will certainly make a rapid start at those
temperatures. You will need to be extremely careful when transferring
to a pot later - unlike many plants a broken root will not branch, it
will die back completely.

Right - I'll be ultra-careful !
Propogator is in the region of 20 - 25 at the moment -
so it's a matter of keeping an eye on it

If the clear plastic cover is restricting
headroom in your propagator, there's nothing to stop you fashioning a
bigger one using stiffish wire and heavy duty polythene.

Very true...
Back at the last place I built a propogator with a soil warming cable
and heavy-duty bubble-wrap - but that was in the greenhouse. Not quite
so well organised here (yet!) - so propogator is on a wide window-sill
in the sunroom..


... Larger tubers are probably better
started in home-made (non-plasticised) cardboard tubes about 10cms.in
diameter and 20 - 25cms. deep.

Hmm - I could certainly make one of these - but then there's the
question of where to put it for the necessary warmth (no sarky
suggestions anybody !)

A warm windowsill would be enough, just don't let it get too cold at
night especially if you've watered it that day.

Good tip - thanks !


Gloriosa tubers are very prone to rotting if the compost is kept too
wet, hence the advice to avoid 'overpotting'.

Not sure I understand the term (......still - bit slow on the uptake
this morning !)

Over-potting means putting them in a pot that is too large in relation
to the size of plant. A small plant with a limited root system cannot
take advantage of a huge volume of compost immediately. The compost
remains too wet for too long, becomes compressed and air-less and
starts to deteriorate, which in turn causes the roots to rot. Plant
roots are stimulated by changing conditions within a pot. As the
compost dries out, they grow in order to 'search' for more moisture.
Keep them growing and you can't go wrong.

Aha - light goes on over head - now I understand...
Many thanks !

OK - currently the tuber is in about 25% vermiculite and the rest is a
'bog-standard' peat compost. I do have a quantity of peat-free compost
- would you think that would be better ??
Don't have any hort. sand..... but I'm sure I can get some...

Well it's a matter of choice. I don't like vermiculite because it
does not improve drainage or aeration in the compost and holds on to
water for too long. Perlite is better - it provides drainage,
aeration and doesn't hold on to excessive amounts of water. I have to
admit that I have never found a truly satisfactory peat-free compost,
but that's a personal thing I can just about live with.

You weren't sure which end was which with your Gloriosa. Generally,
on a fully dormant tuber, the 'active' end will be rounded, fatter and
can be almost toe-like.

Right - when I investigate in a couple of days time I'll see if I can
work out 'which end's up' from your advice

I also have a Chinese Lantern Lilly (Sandersonia aurantiaca) tuber -
which looks broadly the same as the Gloriosa - but on a much smaller
scale - and has two 'branches' joined together in a bulb-like thing.

Any special suggestions for 'which way up' on this one ??

This makes things easier... Sandersonia aurantiaca is quite closely
related to Gloriosa and a complete Gloriosa tuber will look vaguely
like a giant version of the Sandersonia, but without a swollen rhizome
in the middle. The uppermost "bulb-like thing" is a swollen rhizome
connecting the tubers, but the growth will arise from the tips of the
tubers. Sort of 'shoulders uppermost, arms down' with the new shoots
developing at the ends of the arms. A bit of a strange analogy, but
I'm sure you'll be able to see what I mean. If you plant upright with
the 'shoulders' just below the surface of the compost the Sandersonia
will be fine.

Right - I'll re-plant that then g
Thanks !

The same applies to Gloriosa, but because they are quite valuable
suppliers split the tubers and they get at least two for one. A very
well grown plant may produce several tubers and at one time you could
get a complete set for your money, which gave at least two strong
shoots. Not so now

All comes down to money, doesn't it ??

I'll report back when the
sun-room is a mass of vines & flowers with small tropical birds
nesting.

And when you've grown your plant on for a few years with plenty of
tubers to spare, you could try planting one out in a sheltered, sunny
spot in very well drained soil. It can be grown outside in milder
regions (as can Sandersonia and another 'cousin' - Littonia modesta),
but that's another story.

Well - we're quite mild here (far S/W of Ireland, about 3 miles from
the coast) - don't often get frosts, but the 'well-drained' bit would
need a bit of work ! Ground is pretty much waterlogged at the moment -
but nothing that a drier Spring won't solve. Sun's trying to come out
- in-between today's hailstorms. What fun !

HTH.

Yes indeed - many thanks !

Adrian