Colocasia Illustris staying small in size
This is my fist time planting elephant ears in large containers on my patio (in a very moist mix of potting soil and composted manure). I have planted a Colocasia Illustris (Imperial Taro, not a dwarf) and a Colocasia Black Magic. The Illustris was planted from a small independent offshoot, about 8" tall, and the Black Magic was planted from a bulb.
The Black Magic is only 2-3 weeks old, but has now developed a very strong root system, and is growing at a very rapid rate. The Illustris offshoot on the other hand was planted over a month ago, and has remained at 8" tall, with leaves no larger 4". It is sending new leaves as the old ones die out, but they are not expanding in size. For reference, both plants are planted in the same conditions with partial sun, and temperatures currently ranging 50 at night to 80 by day.
Is there a difference in the growth rate between an elephant ear that was planted as an offshoot, and one that was planted as a bulb? It just seems to me like the bulb has more strength due to stored reserves... Should I just continue to wait on the Colocasia Illustris to start growing once the weather is consistently hot? Any tips would be appreciated from those of you who have grown elephant ears from both bulbs and offshoots.