If you ever visited Europe, flower-minded or not, you returned with enthusiasm for the window boxes they have seen-the red geraniums in Germany and Austria, the tuberous begonias of Switzerland… So think how beautiful cities might be if private houses, railroad terminals, apartment houses, department stores, and office buildings could all be decorated with window boxes.
Europeans have had rich experience in growing plants in boxes. We see them high above the streets of London, Dublin, Copenhagen, Paris, Rome, Vienna, Heidelberg, and Geneva. Along narrow, winding streets, they are a charming decoration throughout the growing season. In spring, daffodils, tulips, hyacinths, pansies, wall flowers, and English daisies appear in profusion; in summer, geraniums everywhere radiate their dependable brilliance.
Gardens in Window Boxes
Boxesat windows offer apartment dwellers the enjoyment of a little garden from within or without. If you live in just one room or on a very small property, you, too, can have a window-box garden filled in spring with pansies and primroses, in summer with petunias or fuchsias, and in fall with chrysanthemums. In winter, greens and berries, like bittersweet or California pepper berries with pine, give color. Where English ivy is not exposed to wind, it can provide trailing green all winter.
Size and Materials
A window box must be large enough to accommodate comfortably the plants of your choice. For good results, a window box ought to be at least three to four feet long but not more than six feet. If larger, it is too heavy to suspend and secure properly, and it cannot be lifted easily, even by two people. Boxes resting on broad window ledges and on firm porch railings might be eight feet long, but hardly more since moving them becomes too hazardous. Keep to a minimum depth of eight to nine inches, with a width of ten to twelve inches across the top. Of course, lengths must vary according to the window, or series of windows, or railing to be decorated.
The most common material for window boxes is wood. California redwood, which becomes a neutral gray if not painted, and cypress will last for years. Cedar is recommended, as is a good grade of white pine. Other materials include metals, which are attractive and, for the most part, light in weight. However, they have the disadvantage of conducting heat, thus overheating the soil. Other suitable and durable lightweight materials are plastic, stone, fiberglass, spun glass, and gardenglas.
Choose the Colors
Select a color which will not detract from the plants. Traditional dark green is satisfactory, though commonplace, unless you use a tint like apple green. Have in mind the colors of the flowers, especially of plants that trail over the sides. Dark flowers do not show up against dark paint, as blue browallia or lobelia against dark green or black. The same is true of white flowers against light surfaces, as white petunias against white or pale yellow boxes.
Since houses are painted various colors, some bright, others dark, window boxes can be colored to match. A light blue house, for example, can have dark blue boxes or boxes in a harmonizing color. Against weathered shingles, blue is pleasing.
On a dark red house with white trim, white boxes with blue and white flowers look well, and in all-white boxes, green and variegated foliage plants are attractive. A white house offers every possibility. Boxes may be of red, pink, lavender, blue, gray, turquoise, or rust, although trim is sometimes a factor.
With a bright color like red, limit flowering plants to one color. I once saw a blue house, with white trimmings and blue boxes, planted with large hybrid white petunias -a cool, effective combination. Also delightful were blue boxes, with pink geraniums, white alyssum, and blue lobelia on a white house with blue shutters and trim.
Usually with a traditional house conservative green or black boxes look best. These are the colors of the window boxes on Beacon Hill, Boston, chosen to adorn the nineteenth century brick facades. Where the period is not a consideration white or cream-colored boxes look well on brick.
To hold window boxes securely, use bolts or lag screws and treat them beforehand to prevent rusting. Leave an inch or so of space between box and house for the movement of air. If boxes are to rest on a terrace or other solid surface, raise them on cleats or set up on bricks or blocks of wood so drainage holes won’t become clogged. Some space under boxes is also important for air circulation, which will dry up run-off water.
When you plant a box, put an inch layer of broken flower pots, crushed brick, small stones or pebbles over the bottom to enable water to escape freely through the openings. Above this, spread a piece of wet burlap or a layer of moist sphagnum moss, old leaves, hard coal clinkers or cinders to prevent soil from washing into the drainage area. If you use cinders, first sift to remove ashes, then break up with hammer or stone into half-inch pieces. These will let water pass through, yet retain moisture and some of the fertilizer that washes down.
Soil and Spacing
Plants in boxes need rich soil for luxuriant growth. Space larger kinds-geraniums, coleus, and fuchsias-eight to ten inches apart; smaller kinds-lobelias, annual phlox, wax begonias, sweet alyssum, and browallia-six inches apart. An eight-inch-wide box accommodates two rows of plants, with the tall ones in back and the low ones along, the front. Boxes, ten inches wide, take three rows of plants, tall, medium, and low for edging.
After planting, spread an inch mulch of peatmoss or other mulch over the soil to delay drying out and keep weeds in check. In a month, give a liquid fertilizer and follow up with feedings every seven to ten days. Foliage fertilizers can also be applied, but only as a supplement to root feeding.
Kinds of Plants
The choice of plants for window boxes is limited only by size. Plants over a foot high do not look well unless boxes are exceptionally large. Otherwise, you can grow almost anything you want. For early spring, you might start with Dutch bulbs. In cold regions, these can be purchased already grown, or you can raise your own.
Try hyacinths with pansies or early tulips or daffodils interplanted with grape hyacinths, or basket-of-gold and arabis with scillas, chionodoxas, or leucojum. Include some English daisies and sweet-smelling wall flowers, so common in window boxes in western Europe. Violas, blue phlox, aubretia, and forget-me-nots are other possibilities.
Beauty of Geraniums
The favorite window-box plant is the geranium-red or pink for white, cream, or light or dark blue boxes; white for brown, blue, or red boxes. The familiar trailing variegated vinca is excellent with them. Thriving in sun or shade, the vinca needs constant pinching to prevent it from becoming too long. English and German ivies are other trailers for sun or shade. In the sun, low annuals, dwarf marigolds, lobelias and verbenas make nice edgings as does sweet alyssum, in white, purple or lavender. Petunias vie with geraniums in popularity, and any kind can be planted, though the balcony types have the advantage of trailing gracefully over the sides of boxes.
Ageratum brings “blue” to sunny boxes. Annual phlox, cockscomb, lantana, creeping zinnia, rock rose or lam-pranthus, portulaca, dwarf snapdragons, and dwarf dahlias are also lovely for a sunny set-up.
These for Shade
In shade that is open to the sky, as on the north side of a house, coleus grows superbly, with white-and-green kinds a handsome contrast for those with red-and-pink leaves. Coleus luxuriates in a rich, humusy soil and requires plenty of moisture. Pinch to keep bushy, and to improve appearance remove the spiked blue flowers, unless you especially like them. The Trailing Queen coleus is one of the best.
Other shade-tolerant trailing plants include English ivy and its varieties, creeping jenny, Kenilworth ivy, creeping fig, German ivy, variegated gill-over-the-ground, myrtle, wandering Jew, zebrina, achimenes, chlorophytum, star of Bethlehem or Italian bellflower, and strawberry begonia.
Fancy-leaved caladiums do well in shade, but adapt to sun if they are started directly in the sun from bulbs. In cold regions, start tubers indoors in a mixture of sand and peatmoss in flats or pots and transfer to window boxes when the weather is warm. Tubers need a temperature of 75 to 80 degrees F. to sprout, and will remain inactive for weeks if kept too cool. Tubers may also be planted directly in boxes when the weather warms up, but will take several weeks to make a display.
Patience plant or patient Lucy-in shades of soft rose, pink, peach, scarlet, red, and white-thrives at northern exposures. For trailers you can consider vinca or wandering Jew, either green or variegated, also the silver and purple-leaved zebrina. Tuberous begonias are outstanding performers in window boxes, the large-flowering kinds, with dwarf multifloras along the front. Hanging tuberous begonias create lovely cascade effects in part or filtered shade.
Other plants for shady or partially shady boxes include browallia, with purple cup-shaped flowers, torenia, thun-bergia or black-eyed-Susan vine, pansy, and nemesia. The red, pink, and white wax or semperflorens begonias combine well with grape or kangaroo ivies. A pleasing pair consists of wax begonias and wandering Jew, and these can be rooted from cuttings of indoor plants.
Summer Home for House Plants
Window boxes offer a summering-out place for house plants, provided they are kept out of the scorching sun. Pots can be rested directly in boxes and packed with peatmoss to anchor them and prevent excessive drying. Or cuttings can be taken early in spring to insure a head start. Good trailers among house plants are heart-leaved philodendron, scindapsus, chlorophytum or spider plant, star of Bethlehem, variegated English ivies, strawberry begonia, zebrina, achimenes, German ivy, and lantana, which, though sun-loving, also thrives in partial shade.
Other house plants suitable for outdoor boxes include nephthytis, ferns, alternantheras, foliage begonias, fuchsias, small dracenas, dumb canes, alocasias, maricas, prayer plant, peperomias, asparagus fern, shrimp plant, crown-of-thorns, and bromeliads. If packed in boxes but left in their pots, they can be brought indoors for winter, or cuttings from them can be rooted for the indoor garden.
You can combine hardy foliage plants, like pachysandra with trailing myrtle. You might try hostas, though these are really better in larger boxes or tubs. Ferns, both tender and hardy, green and variegated gout-weed, ajuga, artemisia Silver Mound, and variegated gill- over-the-ground await the imagination of the enthusiastic window-box gardener.
Evergreens and Berried Branches for Winter
After annual plants are lifted, evergreen branches can be inserted in the soil. These will last until spring, when it is time to set out the first pansies. Branches of balsam fir, white pine, red, Scotch, or black pines, and Douglas fir stay green all winter. Spruce and hemlock will shed their needles when it gets too warm, but replacements can be made. In warm areas such broad-leaved evergreens as podocarpus, pit-tosporum, leucothoe, mahonia, and bull-bay magnolia last several weeks and can be replaced from the abundant supply in the garden.
Berries can be added to the greens. Bittersweet is one of the best, but red alder also stays plump and fresh outdoors. Always colorful are California pepper berries, nan-dina, sea buckthorn, and love apples. Cones and gilded or silvered seedpods and branches are festive at Christmas, with artificial berries and fruits as other possibilities. Where squirrels are not a problem, window boxes can also be turned into feeding stations for winter birds.
Windows boxes can be directly planted with small evergreens, needled or broad-leaved. Dwarf Japanese yews are excellent, but small junipers and spruces, bear-berry, leucothoe, leiophyllum, pieris, pachistima, rounded arborvitae and boxwood, where not subject to winter injury, are also candidates. In spring, these evergreens can be planted in the garden and room left again for summer-flowering plants. Or you might have two sets of boxes, one for summer and one to set along the terrace perhaps and bring back for winter.
Large window boxes on firm foundations can be partially planted with small evergreens for year-round green, with geraniums, petunias and other flowering plants added for summer color. In this case, boxes must be large enough to accommodate both groups of plants. Such boxes, often made of concrete, adorn hotels, department stores, restaurants, and business offices as permanent features at windows and doorways.
If you plan to grow evergreens in your window boxes in winter, remember that the plants will need water. In warm sections, where camellias, pittosporum, podocarpus, osmanthus, dwarf hollies, nandina and others are hardy, the soil does not often freeze solidly. Despite cold weather, watering, though less frequent than in summer, is needed. In the rush of the holiday season, this chore is too often overlooked.
When Soil Freezes
In the North, where soil freezes it cannot be regularly watered. Meanwhile plants are constantly evaporating moisture that they are unable to replace. This causes windburning and sunscald. It can be somewhat mitigated by heavy watering whenever there is a slight thaw. These will give roots sufficient moisture for another period of freeze. Gardeners often think that plants in containers do not require watering in winter. This explains why evergreens in window boxes, tubs, and planters are unsightly or dead by spring.
If you do not decorate your boxes in winter, if possible remove and store them until spring. This will prolong their life considerably, for thawing and heaving place a strain on wood or other material. Harmful, too, is the constant exposure to moisture, sun, snow, and ice. Dump soil out, if more is easily obtained in spring, and store boxes in dry place. In winter clean and repair them and apply a fresh coat of paint or stain.
PLANTS FOR WINDOW BOXES IN SHADE OR PARTIAL SHADE
– Fancy-leaved caladiums with German or English ivies or heart-leaved philodendron
– Ferns and coleus with sprenger asparagus
– Multiflora tuberous begonias and small-leaved English ivy
– Patience plant and torenia with vinca or English ivy
– Pink or red wax begonias and variegated vinca
– Red and white wax begonias with green or variegated wandering Jew
– Upright coleus and coleus Trailing Queen
– Upright coleus and vinca or English ivy
– Upright and hanging tuberous begonias Upright and trailing fuchsias
– Upright fuchsias and star of Bethlehem, both blue and white
– White, pink, and red wax begonias alone or with German or English ivies
PLANTS FOR WINDOW BOXES IN THE SUN
– Calendulas with lantanas California poppies with ageratum Dwarf marigolds with ageratum and vinca Geraniums with petunias and vinca
– Geraniums with ageratum or lobelia and vinca
– Geraniums with German or English ivies
– Geraniums and lantanas
– Geraniums with variegated gill-over-the-ground
– Geraniums with lobelia or ageratum and annual phlox
– Ivy geraniums and double petunias
– Lantanas with ageratum or lobelia
– Lantanas with dwarf marigolds
– Petunias with verbenas
– White geraniums with dwarf salvia and lobelia
– Zonal and ivy-leaved geraniums