Amorphophallus titanum… Sadly Not!

During the initial stages of my work in the glasshouse I found a dormant, six litre pot, labelled as Amorphophallus sp. I was pretty excited about it and set it aside for monitoring. Amorphophallus is such a cool genus. Everyone knows A. titanum, sporting the largest unbranched inflorescence in the world. A. titanum is a regularly advertised attraction at Botanic Gardens worldwide, at the Royal Botanic Gardens Edinburgh A. titanum has its own twitter account. 
My favourite species has to be A. paeoniifolius. Cultivated as a food crop in Africa and South Asia. This species forms corms weighing up to 8kg, within a year. The inflorescence is much smaller than that of A. titanum, but still manages to reach 80cm high. The foliage is an impressive sight too, rising up to two metres. The stems have the fantastic blotchy patterns often attributed to the genus. I hope to get some seeds soon.

The image above is not mine, link to the owner.

When shoots finally emerged I quickly realised this isn’t Amorphophallus at all, the plant is in fact Typhonium venosum. Though the growth of T. venosum does look similar to that of Amorphophallus sp. the leaf shape is distinctive. T. venosum is common in cultivation and the plant matched an entry in the records, its now labelled with its accession.
The pot contained a rotten central corm with a few larger offsets shooting, surrounding these were around 20 small corms. I repotted the small corms into 5cm pots and the large corms into 11cm, all foliage was removed. They grew well and today I moved them back in six litre pots, though now we have four. I put a larger corm in the centre then four small ones surrounding, five per pot. Again almost all foliage was removed. I expect nice strong clumps in a few weeks, the small corms have already made a huge amount of growth.

T. venosum stems shown above.

A small T. venosum corm, above.

Potted small corm after six weeks, above.

A finished six litre pot today, above.


Material: Plants

Action: Transplanting 

Treatment: None

Medium: 8:5:2:2 Coir:Perlite:Tufa:Vermiculite + osmocote 

Irrigation: Drippers, 2L daily


Divisions Growing

Over the past few weeks I’ve divided a number of species. Various Alpinia sp. Curcuma longa, Hedychium coronarium, Colocasia esculenta, Zingiber officinale and more. Some of this work I have shared here. Lots of the larger divisions in the 11cm pots are beginning to shoot. The photos below show them in the glasshouse.

Moving plants out of the glasshouse has freed up lots of space. Over the next week I will be undertaking a lot more propagation. Expect to see plenty of cuttings and divisions, hopefully some interesting plants too!

Colocasia esculenta, Nodal Division 

A large volume of plant material will be needed to fill the new tropical glasshouse. As I begin moving plants out of the storage glasshouse I’m looking to fill this space. This has led me to maximise the propagation material available to me. Lots of the perennial species in the collection are rhizomatous. I am therefore trying to use the smallest pieces of rhizome possible to produce clones. A plant I’ve done a lot of work on recently is Colocasia esculenta.
C. esculenta is a tropical perennial which is grown as a food crop. Known to have been in cultivation since 5000 bc it’s impossible to know the plants native range. C. esculenta is believed to be one of the earliest known cultivated crops. This makes it an important species for the tropical crop display.
A few months ago we had only two plants. Both were in fairly poor condition, the soil was depleted and the plants root systems were girdled. Since repotting the original plants I have been testing a variety of division techniques, trying to be more and more efficient.
I figured out C. esculenta can be rooted from tiny sections of rhizome as long as that section has one active growing point. The section of original rhizome eventually rots away as the growing point shoots and roots over it. 
Despite being able to take very small sections, I found the density of visible growing points per rhizome very low. On a 10cm rhizome there would be up to four growing points visible. In the past I have experimented with submerging plants to encourage adventitious root formation. I decided to try submerging the plants rhizomes for 72 hours. This stimulated a large amount of growth, shown in the photos below.

Once the growth points are showing they can be cut from the rhizome in small sections. The photos below show the sections being cut, covered with rooting hormone and placed in a tray of 1:1:1 coir:perlite:vermiculite mix. When working with rhizomes or roots I use osmocote in my compost mixes, unlike for stem cuttings. I don’t see any logical reason to exclude nutrients from a root section and from my own observations I think it increases the rate of plant formation.

(The tray above was filled to the level of the growing points)

Material: Rhizome
Action: Nodal division 
Treatment: Rooting hormone
Medium: 1:1:1 Coir:Perlite:Vermiculite + osmocote
Irrigation: Handwater, twice daily (kept in shade)
Finally the photos below show the rooted growing points being potted on. Some plants already have leaves and I expect the others to follow soon. From one rhizome I produced ten plants.


Material: Rooted offshoots

Action: Repotting 

Treatment: None

Medium: 2:1:1 Perlite:Tufa:Vermiculite 

Irrigation: Handwater, Twice daily