Bulbs for Beautiful Pot Plants
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.
Actually, it is not the freezing of the soil that injures 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, bulbs are bruised and thrust out of the soil, their roots torn. Where there is no hard freeze, but sufficient cold weather, hardy bulbs can be grown successfully in containers of small size.
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 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. 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, frostproof room or greenhouse in winter. This is an old-time favorite, often seen in gardens of Europe.
Calla Lily. Showy, hardy 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 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 with white-spotted leaves. Rest bulbs after foliage ripens and grow again.
Dahlias. Colorful and free-flowering, they 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 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, frostproof place, they can be grown for years. Check bulbs during winter, and if shriveling, sprinkle lightly.
Gladiolus. Summer-flowering with spearlike leaves and many hued spikes. Corms can be planted in containers outdoors after danger of frost is passed. Set them six inches apart and four to six inches deep. If several containers are planted every two to three weeks, there will be a succession of bloom. 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 thrips. Store corms in a dry place at 45 to 55 degrees F.
Gloxinias. Summer-flowering 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.
Lilies. Gorgeous and hardy, with blooms in many colors. It is now possible to have a lily container garden, with flowers from May to frost. Open the season with the dainty Lilium pumilum and continue with madonnas, Golden Chalice hybrids, Olympic hybrids, auratums, and specios-ums. Lilies can be planted in fall, like daffodils and tulips, and they will also flower from bulbs set out in early spring. In cold regions, the rules for Dutch bulbs outdoors in winter apply also to lilies, which do well in large planters, two feet wide and two feet deep. Group several of one variety for a good effect. Plant smaller sizes in individual six or eight inch pots to be wintered in coldframes. Plant larger sizes in eight or ten inch pots. After flowering put containers out of sight while stalks ripen.
Nurserymen and florists offer pot-grown lilies in early spring ready to plant in containers without disturbance of roots. Try combining several in large containers, with English ivy, vinca, grape ivy, dwarf annuals, or other low plants for softening effects. After flowering, bulbs can be planted in the garden, grown again in containers or given to friends.
Tuberose. Tender and summer-flowering with narrow foliage and tall spikes of single or double white flowers, fragrant and long-lasting. Where seasons are short, bulbs are best started indoors six to eight weeks before planting outdoors. Plant in six-inch pots and feed with liquid fertilizer. Tuberoses need rich, well-drained soil and full sun and staking of the tall spike. Since bulbs do not flower well a second-year start with fresh stock each spring.