As a group, bulbs are outstanding plants-colorful, showy, and generally easy to grow. Many have evergreen foliage; with others, the leaves ripen after flowering and the bulbs are stored and started again, year after year. Some bulbs are hardy, others, tender, though what is and is not hardy in a particular area is a matter of winter temperature averages. In cold regions, tender types-tuberous begonias, gloxinias, calla lilies, and gloriosa lilies -can be treated like summer container plants. This gives the gardener a wide variety to grow from earliest spring to late fall.
Included in this group are crocus, snowdrops, eranthis or winter aconites, chionodoxas, scillas, grape hyacinths, leucojums or snowflakes, Dutch hyacinths, daffodils, and tulips, the pride of northern spring gardens. Though hardy, they are not adapted to containers outdoors where
temperatures drop much below freezing. They require the protection of a shed, unheated cellar or coldframe. Pots can also be dug into a trench in the ground for the winter and covered with a thick blanket of marsh hay or straw. Where temperatures do not go below freezing, Dutch bulbs can be left outdoors in containers over the winter.
For best results, start with fresh, firm, large-sized bulbs each fall. Insure good drainage in the bottom of each pot and use a light soil with bonemeal added. If in clay pots, plunge during the rooting period in damp peatmoss to prevent rapid drying out. If this occurs too often, roots will be injured and flowers will be poor. When weather permits, after the danger of freezing passes, put containers outside where they are to flower or in a nursery row until they reach the bud stage. After blooming, place containers where foliage can ripen unseen.
For fragrance, concentrate on Dutch hyacinths, excellent for bedding large planter boxes or raised beds. Daffodils look well grouped around trees or large shrubs, as birches and forsythias. Tulips, formal in character, combine delightfully with pansies, violas, wall flowers, forget-me-nots, marguerites, English daisies, and annual candytuft.
As already indicated, in cold areas, Dutch bulbs cannot
be potted or planted in small window boxes and left outdoors unprotected for the winter. They can, however, be set out in large planters and boxes, deep and wide enough to contain plenty of soil. Containers should be one and a half to two feet deep and about two feet wide. Set bulbs, with at least six inches of soil above them, planting them early enough in the fall so that they can make root growth before soil freezes hard. In penthouse gardens in New York City, Dutch bulbs have been grown successfully in this way, but it is always a risk. It makes no difference whether containers are made of wood, concrete, or other material; it is the amount of soil they hold that counts.