As a group,flower bulbs are outstanding plants—colorful, showy, and generally easy to grow for container gardening. Many have evergreen foliage; with others, the leaves ripen after flowering and the bulbs are stored and started again, year after year. Some flower 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, and calla lilies—can be treated like summer in container gardens. This gives the gardener a wide variety to grow from earliest spring to late fall.
Dutch flower bulbs include 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 garden containers outdoors where temperatures drop much below freezing. They require the protection of a shed, unheated cellar or cold frame. Gardening 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 flower bulbs can be left outdoors in gardening pots over the winter.
For best results in a container garden, start with fresh, firm, large-sized flower bulbs each fall. Insure good drainage in the bottom of each garden pot and use a light soil with bone meal added. If in clay pots, plunge during the rooting period in damp peat moss 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 your container garden outside where they are to flower or in a nursery row until they reach the bud stage. After blooming, move your container garden 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 in container gardens.
As already indicated, in cold areas, Dutch flower 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. The garden pots should be one and a half to two feet deep and about two feet wide. Set flower 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 garden pots are made of wood, concrete, or other material; it is the amount of soil they hold that counts.
Actually, it is not the freezing of the soil that injures flower bulbs (this occurs in open ground), but it is the pressure and counter pressure exerted by frost on the sides of containers, which are firm and do not give. As a result, flower bulbs are bruised and thrust out of the soil, their roots torn. Where there is no hard freeze, but sufficient cold weather, hardy flower bulbs can be grown successfully in garden containers of small size.
Here is a partial list of flower bulbs that thrive in container gardens. They will help you with your container garden design。
Achimenes are warmth-loving trailing plants with neat leaves and tubular flowers in blue, lavender, red and white. Related to gloxinias and African violets, they are nice in hanging baskets and window boxes or in garden pots on tables, shelves, or wall brackets. Start the small tubers indoors and give plants a sheltered spot with protection from strong sun and wind. Achimenes, an old standby in the South, is worthy of more frequent planting.
Agapanthus or Blue Lily of the Nile is a fleshy-rooted evergreen plant, with strap leaves, often grown in tubs and urns on terraces and steps during the summer, when the tall blue spikes unfold. Culture is easy, but plants require a well-lighted, frost proof room or greenhouse in winter. This is an old-time favorite, often seen in the gardens of Europe. It is a perfect flower bulb for container gardening.
The Calla Lily is Showy, and outdoors in warmer regions, but a tender pot plant in the North. Most familiar is the white one with large, shiny, heart-shaped leaves. Start bulbs indoors in February or March in rich soil and, when weather settles, transfer to large gardening pots and take outdoors. Calla lilies do well in full sun or part shade, are heavy feeders and need much water. There is also a dainty yellow one with white-spotted leaves. Rest your flower bulbs after foliage ripens and grow again.
Colorful and free-flowering Dahlias provide bounteous cut blooms. Tall, large-flowering kinds can be grown only in large planters and boxes, but the dwarfs, even freer flowering, are excellent in small garden containers. Attaining one to two feet tall, they grow easily from tubers in average soil in sun or part shade. They may also be raised from seed sown indoors in February. If tubers are stored in peat or sand in a cool, frost proof place, they can be grown for years. Check bulbs during winter, and if shriveling, sprinkle lightly.
Gladiolus, the summer-flowering plant has spear like leaves and many hued spikes. Corms can be planted in garden containers outdoors after danger of frost is passed. Set them six inches apart and four to six inches deep. The best way to use these in container gardening is to planting a few every two to three weeks, giving you a succession of bloom in your container garden. Stake stems before flowers open. After the leaves turn brown, or there is a frost, lift corms, cut off foliage and dust with DDT to control the tiny sucking thrips. After dusting, store corms in a dry place at 45 to 55 degrees F for future planting.
Gloxinias, another Summer-flowering plant and tender with large, tubular blooms of red, pink, lavender, purple, or white, and broad velvety rosettes of leaves. Start tubers indoors and don't take outside until weather is warm. Since the leaves are easily broken or injured by wind or rain, put plants in a sheltered spot. The low broad eaves of contemporary houses, with restricted sun, offer an appropriate setting for rows of pots or window boxes filled with gay gloxinias.
