Grass Trees are very slow growing with mature plants being centuries old.
Grass Trees only grow in Australia.

These remarkable plants have a lifespan of 600 years but are very
slow-growing. The trunk takes a decade to form initially as it is composed
of a mass of old leaf bases held together by a natural resin. It is then a
further 20 years or more before the mass of thin, linear leaves rises above
it. From then on, it grows only about 1-2cm (0.4-0.8in) in height per year.
We have observed plants which have taken 27 years to grown 30 centimetres
(one foot).

This plant grows to a height of over 4 metres and often has branches. It's
growth rate is only about 1 metre every 100 years. However, the flowering
stalk grows at a rate of 2 - 3 cm per day reaching to a height of over 3
metres. Mature plants will result in flowering every 2 - 3 years.