It's an agave plant Maisie. it only blooms once when 10 to 25 year old, then dies. As it decays into a pile of mush as I said, the stem falls over and all these little things at the top spread thousands of seeds for new plants. I planted this one about 16 years ago as a thumb-sized plant. Another one planted (read: stuck in the stony soil) at the same time bloomed a couple of years ago.
İf you go to Datça you will see loads of them at the beach restaurants festooned with lights. Not live ones - they cut them when they bloom. dry them and paint them. Very decorative and useful.
Now I know what it is (thanks to all those who responded), I looked it up in Wiki.
Interesting plant. Also, it says that some plants have been known to take 60 years to flower!I So planted for a baby at birth, they could be nearly pensioners before they see the flowers.
I asked because this looked similar to a plant which grows next door. It is about 12-14 feet high, so not the same. Many years ago, we cut this down for the elderly lady who lived there. It was growing in a silly place, and she wanted it gone. Obviously, we didn't get all the root out.
The house was later split into two flats, and this plant grows at the bottom and to one side of a flight of stairs from upstairs. It now 'belongs' to the upstairs flat after garden division. There have been a successioon of people living there, and the current tenants are 'garden-blank'. I have seen the chap cutting forsythia back with an ordinary pair of scissors! Plonker!