Ironhard Tacky is a... Discworld plant grown by a Nanny Ogg. What it may be related to is unknown, as are its uses. There are rumors, however....
The hard and long green-blue stems of Ironhard Tacky sprout incongruously violet and orange flowers in late summer. Some people believe the plant could be used as an aphrodisiac, but nobody has ever found a way to make it digestible.
It is not poisonous to eat. On the other hand, except for being very hard to eat, nothing appears to happen if one does consume it. This is very surprising given who grows it. Perhaps only Nanny Ogg knows the secret of the Tacky.
Ironhard Tacky can be found in the following locations: