Most ikebana arrangements are made with two or more types of plant matter that are used as line materials and auxiliary plants. Generally, the first sets the framework of your arrangement and the second supports and completes your arrangement.
The basic structure of a traditional ikebana arrangement is based on the scalene triangle, whose sides are of three different lengths. Given their unequal sides, an ikebana arrangement is always asymmetrical. Yakueda or Shushi refers to the three main line materials that form the basic structure of most traditional arrangements. The individual names of these three lines vary among schools, but they can all be represented using branches, flower stems, or leaves that can be mixed or matched according to your vision.
When using branches from bushes and trees for line materials, look for ones with graceful lines and with interesting radiating smaller branches. Look at the leaf formations and any buds, blooms, or berries on them. You can always cut or trim away parts of the branches to meet your needs. And you can shape some flexible branches by gently bending them with your hands. Other than regular branches, materials like pussy willow, equisetum, grasses or curly willow make excellent line material.
Line materials can also include flowers. Look for ones that have interesting blossoms and sturdy stems and stalks with long lines. Select colors that complement each other. Large and linear leaves of a floral plant or even palm leaves can also be used as line material.
Auxiliary materials can be an other plant material or flower. Many schools keep in mind the sessonality of materials