Which Part to Bury? : How to Determine the Top of Caudex Bulbs.
Most often, caudiciform plants are sold as naked tubers. No leaves, no roots, as is and just like a potato or a ginger. Question is, which part goes in the soil?
Find the Upshoot.
Inspect your bulb and there should be 2 points that has tiny nubs on each ends. You'll find that on one side, the nub will look more like a "belly button" with protruding 'button' in the centre whereas the other side has small indent dots on it; showing the previous root points.
☘️ Erecta has only 1 growth point, unlike Suberosa & Kaweesakii (fka. Sp. Nova). A few branches can sprout out from this 1 growth point, giving it a much lusher look.
Pointiest at the Top.
From first glance, you can identify the top of bulb; the pointiest one. You'll find several old stem growth points on it. The 'fatter' portion of the bulb is the store point for water and it should go in soil. Depending on the size of your bulb, you can bury the bottom halfway in the soil or fully (also depending on your aesthetic 😉). Good rule of thumb is, at least 50% of the bottom portion is to be buried in.
☘️ Phyllanthus Mirabilis has multiple growth points, but all in 1 area/cluster.
Pointiest & Barky-est at the Top.
Similar to Phyllanthus Mirabilis, it is obvious at first glance which part goes in the soil. But for Firmiana Colorata, an extra physical sign is the top portion is a lot barkier & darker looking than the bottom portion. And similar to Phyllanthus Mirabilis, you'll find several old stem growth points at the top and a 'fatter' portion of the bottom bulb as well. Good rule of thumb is, at least 50% of the bottom portion is to be buried in.
☘️ Firmiana Colorata has multiple growth points, but all in 1 area/cluster.
STEPHANIA KAWEESAKII (FKA STEPHANIA SP NOVA)
Smoothest to the Bottom.
Kaweesakii growths are irregular and totally random, which is why they are the unique ones out of the Stephanias family. Since the growths are irregular, it is usually hard to detect where the bottom is if it's a completely bare root bulb like the pic below. In many cases, I find that the most jagged surface is the top of the bulb which is a total opposite with other caudexes! So when in doubt, just ask the seller to point/mark the top of the bulb for you.
☘️ Stephania Kaweesakii has multiple growth points and it is random throughout the top of the bulb.
Bunched Up Bottom.
Unlike Erecta, although there's a growth point at the top, their stem growths are random but still within/around the point. Although sometimes both sides might look similar, one side will have a more protruding look and the top will usually have a more 'sunken' look. Good rule of thumb is, at least 50% of the bottom portion is to be buried in. ☘️ Stephania Suberosa has random growth points but all in 1 area/cluster.
Burying Wrong Side of the Bulb?
So you've determined the top side and you've buried them properly. Months and months goes by and still no sprout?! I would usually check the other side of the bulb.
Yes, it can happily sprout in soil too! They generally look quite short, with thick pink/pale sprout (almost milky white in color due to absence of light and thick stumpy stem from being filled with water). It almost looks like a tiny bean sprout! Just switch the sides around and continue the same potting routine. You'll notice the sprout will become greener in color in time and taller too - depending on your lighting condition.