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  Cultivation of Taccarum
From: "Marek Argent" <abri1973 at wp.pl> on 2011.12.03 at 17:36:23(22443)
Hello,

I've had Taccarum weddellianum since 2005, every year it produces a leaf and usually a "baby" tuber.

But... it doesn't grow in size almost at all, although the tuber very slowly increases, the leaf is 20-30 cm tall every year.

I use regular pot soil, and the plant is fertilized with natural biohumus.

It grows in a southern window.

When it's dormant I store it without soil in the normal room temperature.

What do I do wrong? What should I do to make it grow larger?

Here are photos of my plant:

http://abrimaal.pro-e.pl/araceum/taccarum/weddellianum.htm

Please help,

Marek

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From: "Ertelt, Jonathan B" <jonathan.ertelt at Vanderbilt.Edu> on 2011.12.08 at 07:54:43(22454)
Marek,

Greetings. As usual, I have no magic answers Ė but I have had them get larger and come along and flower. I guess originally just judging from the size the leaf was getting to I overpotted, and then watered and fed the plant abundantly. I have multiple new ďbabiesĒ every year, but I also have had several of the impressive flowers come along. I donít pull it out of the soil during the winter, and in the old greenhouses it would even get hit occasionally with water while dormant (the death knell for some, but not this one). Hope this helps. Good Growing.

Jonathan

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From: Hannon <othonna at gmail.com> on 2011.12.08 at 15:31:05(22458)
Marek,

It looks like your mix does not dry out at all. I recommend allowing the surface of the soil to dry completely between waterings. Also, the soil in the pot should come right up to the brim so that the plant+soil does not sit so low in the pot. I have done well with this species in a mix of peat+sand+perlite. When the leaf is fully formed the plant is thirsty and dries out a lot between waterings; this does no harm and in fact may help. My plants are also pot-bound-- the largest blooming specimens are in 8" pots. Keeping plants pot-bound in general is of great benefit to a wide range of species.

I wonder if you might have here T. warmingii instead? Essentially the same culture.

Best of luck,

Dylan

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From: Zanezirklejr at aol.com on 2011.12.09 at 05:53:02(22459)
Your problem is taking it out of the soil, it needs to be kept in the pot and moist at all times, also needs to be outside not in a window.

In a message dated 12/7/2011 11:47:28 P.M. Eastern Standard Time, abri1973@wp.pl writes:

Hello,

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From: Hannon <othonna at gmail.com> on 2011.12.09 at 18:46:29(22461)
Agreed that keeping it in its pot when dormant is a good idea, as with all geophytes. But Taccarum should be kept DRY when dormant. This is true for probably most but not all tuberous aroids.

On 9 December 2011 05:53, wrote:

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From: "Marek Argent" <abri1973 at wp.pl> on 2011.12.12 at 11:02:14(22469)
Dear Hannon,

I keep all tubers dry when they're dormant, even I dont water them until the new bud grows enough large to break.

As for the soil - should the tubers stay in the old soil during the dormancy or should I change it as the roots wither

or when it starts to grow again?

In all the methods there are good and bad things.

1. Leaving the tuber in the old soil means leaving it with all pests and the soil itself often remains wet too long at the bottom of the pot what may cause rotting. Next season the tuber can start to grow too early and repotting it while producing new roots may be fatal.

2. Repotting it shortly after the leaves wither - the new soil left dry for a few months loses its moisture and structure, it turns into dust and sand.

So when is the best time to change soil in pots?

Marek

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From: Hannon <othonna at gmail.com> on 2011.12.12 at 16:38:17(22473)
Dear Marek,

The best protection for dormant tubers is the soil that surrounded them in the growing season. It acts like a perfect cocoon. A tuber will have greater exposure to pests and desiccation if taken out of its soil. The idea of unearthing bulbs and tubers after the growth period persists in many hobbyist circles and I believe it is the wrong approach in most cases.

1. Attentive culture should result in no pests in the soil at all. Such pests should be evident in the growing season and treated then, especially root mealy. When withered leaves are removed I push some soil into the hole left by the petiole to prohibit entry by ants, mealies, etc. When the soil dries out as the leaves yellow there should be no moisture at all at the bottom of the pot. "Dry soil" is not as dry as you might think and will retain some beneficial moisture for months while the plant is dormant. (This can be demonstrated by allowing a few small weeds to stay in the pot and observing them 5, 10 or 15 weeks later after zero watering). When they have had a good season (in plastic pots) aroid tubers/corms will often distend the pot so that it is firm and compact; this 'package' is the ideal state for storage over winter (or summer).

2. At the beginning of the season I wait for new shoots to emerge and repot then, when the plant is active. If they are slow to wake up I will water well just ONCE and see what happens. If nothing happens after a few weeks then I unpot and look for signs of trouble. Unless the new roots are well along (with secondary branching) it is easy to transplant a plant starting its growth. In fact, I often wait until a leaf is formed and then shift to the appropriate next size pot. Usually this does not involve disturbing the root ball at all. Note: some geophytes like amorphos and their kin seem to need repotting every 1-2 years while others (including Biarum) can go on for a number of years before new soil is needed. Keep in mind that any soil mix used by a plant that is dormant half the year is only on duty for about six months. Any soil mix that is exhausted in six months is hardly worthy of the name. The addition of coarse sand helps the longevity of a mix substantially.

It can be difficult to gauge the need of a plant for a particular pot size until it is in full growth and it is impossible to know the vigor of a plant until it is growing. Vigor-- not necessarily tuber size-- determines pot size as well as watering needs and the two are closely related. I prefer a smaller pot that needs more frequent watering rather than a relatively large pot that takes too long to dry out. Soil in a container that takes weeks rather than days to dry and justify the next watering is a sign that the pot is too large for the root system. It is important to let the soil surface go very dry between waterings, assuming everything else is in order. I grow over 70 amorpho species and hundreds of other geophytes in 'cramped quarters' and these techniques has been successful to date.

Dylan Hannon

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From: "D. Christopher Rogers" <branchiopod at gmail.com> on 2011.12.14 at 07:15:06(22478)
Hiyer, Dylan!

What are your local humidity levels? It seems that the more humid you are, the harder time one will have keeping the soil in the pots dry.

Christopher

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From: Hannon <othonna at gmail.com> on 2011.12.14 at 20:15:24(22480)
Hi Christopher,

That is a good point. The "average humidity" for nearby Pomona is 43%,
which in reality means daytime humidity mostly <43% and nighttime humidity
over 43%, often reaching the dew point. The Los Angeles area is a semi-arid
zone with a strong coastal influence. It is not a desert.

The drying of the soil we are concerned with is toward the end of the
growing season and during the dormant period. A plant that has just lost
its leaves by yellowing and withering should already be in relatively dry
soil. It should not be watered until the next growing season in most cases.
If the plant has had a good season with vigorous root growth then this root
system will help pull water out of the soil just before the leaves die
down; the roots are dying back at this point also. Dormant tubers should
not be put away wet so to speak but I don't know if humidity alone is
enough to prevent soil from drying "enough". This issue will vary between
species and genera.

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From: "Derek Burch" <derek at horticulturist.com> on 2011.12.18 at 14:19:33(22485)
Dylan, and anyone else who would like to join in,

Organised notes on this would make a great article for Aroideana, and if
several people want to put in their own experience it could swell to a neat
little 'horticultural' item.

Derek

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From: Hannon <othonna at gmail.com> on 2011.12.19 at 14:23:33(22489)
Derek,

Do you mean something like "Caring for dormant tuberous aroids" ? Or
something broader about growing tuberous aroids in pots? I agree that a
detailed essay in either area would be helpful to many growers. I am happy
to contribute however I can.

Dylan

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From: "Derek Burch" <derek at horticulturist.com> on 2011.12.20 at 10:57:29(22493)
Dylan,

It was the correspondence about what to do when the aroids are dormant that
got me thinking about this, but if you would care to expand it to the
broader topic I think that it would be a great contribution. Thank you for
considering this. Derek

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