Trellis was first offered in the very late 1920s. The flatware is basically the same as the Newell shape, but has periodic embossings on the rim of two different trellis designs. The hollowware has a flattened look in contrast to Newell's rounder shapes.
The line was used as a basis for Quaker Oats promotions. Such pieces are marked simply, "Trellis." Otherwise, most items will carry the general HLC backstamp. If a piece of Trellis has a single digit such as a "1" or "2" as the year for the date code as in B 1 N 8 or D 2 N 8, this it is from 1931 or 1932. Many make the mistake these are from 1921 or 1922.
Most treatments used on Trellis are stylized floral decals but some solid colors exist such as green and light yellow -- two glazes popular in the Depression era. Another type of treatment unique to Trellis involved the handles and finials with hand-painted trim work in either green, red, orange, black, and platinum in various combinations on the light yellow glaze.
Trellis flatware isn't terribly difficult to locate, but the hollowware is a different story. The line was discontinued shortly after 1932 making its production run less than six years.