Only a few bulbs lend themselves to formal plantings, but these can create some striking effects. The classic bulbs for formal plantings are tulips, usually planted in large numbers of the same variety. They are particularly effective when underplanted with other flowers in contrasting or complementary colors. Violas, grape hyacinths, alyssums, wallflowers, forget-me-nots, candytufts, and primulas are all used for underplanting.
Formal plantings are costly and difficult, but stunning. The effect comes partially from the uniformity and precision of the planting. To achieve this precision, new bulbs of a uniform size must be bought each year. The bed must be excavated and leveled, the bulbs set precisely in place and covered, and then the companion flowers planted.
Massed to accentuate the erectness, density, and uniformity of their spikes, garden hyacinths are particularly effective in formal beds. Daffodils, Dutch irises, or bearded irises can also be used for formal spring displays; and lilies, dwarf cannas, or the larger alliums are good for summer displays.
A formal effect can also be achieved with identical containers of bulbs arranged symmetrically—for example, matching urns of tulips flanking steps or a walkway. But in most gardens, bulbs are easier to use and more appropriate in an informal setting.