The Sogetsu School was founded in 1927 by Sofu Teshigahara.
Trained  in  the traditional  philosophy  of  ikebana, Sofu had  an  independent
spirit  and  wanted  to  express himself  freely  through  the  arts.  His  vision  of
Ikebana was that it could be made by anyone,  anywhere ,  using any materials.
 He  is  the  one  who  elevated  ikebana from an attractive craft to  a form of art.
Time magazine called him the "Picasso of the Flowers."

This zen'ei ("avant-garde") ikebana style, in which freedom of expression is
preeminent,  appeals  to  contemporary  tastes by largely disregarding the classic
formal  rules  (even  though  it  still  stays  deeply  rooted  in  Japasese  tradition).

All  sorts  of  materials can be used  (without it being  compulsory)  in addition to
  fresh   plants and flowers  like  withered  branches,  roots,  driftwood,  iron,  stone,  
and  all sorts of unconventional materials.

To learn more about ikebana an Sogetsu MarieLN invites you to read
KADENSHO, The book of Flowers by Sofu Teshigahara