I live in the Czech Republic and cycads grow about 15 years.
Most Encephalartos directly imported from SA.
You will find some interesting reading to grow here in Europe
Unfortunately, I do not know France and even my English is not too good
Here some photos from the collection






Ngoyanus

Cupidus

Alti x trispi


Msinganus

Horridus

Hildebrandtii

All larger and more stable from April to September are grown outdoors
Only small seedlings in the greenhouse are.


Josef