Less is more when it comes to woody stems, like quince, cherry, and dogwood. Select just three or four sculptural specimens, and use a heavy oblong vase that’s about a third as tall as the branches. Aim for an asymmetrical spray so the branches reach rather than lean.
For stiff-stemmed flowers, like roses, irises, and mums, a low cube guarantees a graceful grouping. Remove all but the top leaves, which add color while they frame and differentiate blooms. Work in loose layers, weaving stems together to form a mound. Dense arrangements are forgiving: Even if you snip too short, it’s easy to fix the overall shape, because the blooms support one another. Push and pull so that the final product looks natural—slightly imperfect. Set on a coffee table; the best view is from above.
If you constrain tulips (or calla lilies or ranunculus) about two-thirds of the way up with a cylinder vase, the natural arc of their soft stems will take care of the arranging.