Rosebuds and newly opened blooms can be arranged in different lengths in a tall vase or just one in a bud vase or small snifter. Avoid full mature blossoms; although beautiful, they will release pollen into the water causing it to yellow. Also, leaves must be removed to avoid mold.
Stems of tiny carnations in tall cylindrical glass vases not only look attractive but have longevity as far as flowers are concerned. Since all flowers have the tendency to float, carnations have hardy stems that are easily weighed down using fishing line and sinkers.
Although vines of blooming orchids may be more challenging to weigh down than those of other flowers, the lineal effect of the blooms of species such as dendrobium and vanda are well worth the work. All or part of the vine can be submerged in water, or the upper part may be out of the water and cascading down the outside of the vase. Single orchids may also be displayed in glass bowls.
A spring event can use tulips or daffodils. Their strong stems and linear shape work well in tall cylindrical vases. Also, because their new blooms hold together well, they can be placed either singly or in small groups in bloom bowls. Use newly opened buds to discourage pollen pollution in the water. Tulips and daffodils also have "clean" stems which mean that they do not have hairs or fibers on them to trap air bubbles.
All types of lilies, especially the gloriosa lily, the sandersonia and the calla, work well in water. The multiple flowers of the gloriosa lily and the sandersonia give continuous color throughout the tubular vase, and the stem is strong enough to anchor them securely. The calla lily, with its long, graceful stem and waxy bloom, works well in submerged arrangements. The stem is easily weighed down, and the waxy, stiff, thick petals resist mold and do not get water-logged easily.
The red or pink amaryllis makes excellent underwater centerpieces, as does the white with burgundy markings amaryllis. Their long stems are hardy and their colorful blooms large, so they work best in larger vertical vases or in single blossom glass bloom bowls.