Does anyone know what cultivar of Sequoia sempervirens this might be? We purchased it as 'Glauca', but that is supposed to be an upright tree. This cultivar is dwarf with a twisted trunk and long, horizontally stretching limbs. The leaves are a bit more glaucus than the species. I can't find any reference to a cultivar like this.
Could still be 'Glauca' - if it was propagated from a small side shoot, it can continue to grow as a 'branch' rather than a tree, and may take decades (if ever!) to develop normal apical dominant tree growth.
This sounds drastic, but worth remembering that Sequoia sempervirens regrows well from coppice: cut it down at the point where the trunk ceases to be straight (at the base if necessary!) and let it regrow from the stump. The new regrowth is very likely to develop a good tree shape. Then all you need do is thin out any competing multiple new stems to a single trunk after a year or two. The regrowth will be fast, a metre or two per year easily.