In the old days, window boxes and pots got filled zonal geraniums (Pelargoniums), some variegated trailing vinca (Vinca minor) and perhaps some “spikes” (Dracaena). Although all of those plants are still available for people who want them, there are scores more to choose from. In fact, there are so many annuals and tropicals available that sometimes it can be hard to choose. Here are some tips for filling window boxes and some suggestions for reliable plants for season-long flowers.
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Think of your container components as Spillers, Fillers and Thrillers. Spillers hang over the edge of the box or pots, Fillers are the mounding plants that create the body of the arrangement, and a Thriller is either a tall, upright element or plants with leaves that aren’t green.
Spillers
Variegated ivy makes a good spiller for boxes that are in shade.There are several varieties of begonias that cascade and are perfect spillers in boxes and pots in shade.Sweet potato vines come in purple, bronze, lime green or variegated. These can be used for spillers in sun or shade boxes.Variegated Plectranthus, commonly called Swedish Ivy, makes a good spiller for sun or shade.Scaevola is a flowering annual that comes in lavender-blue, white, pink or bi-colors. This is a good spiller for boxes in full sun.The shorter varieties of Mandevilla vine, formerly called Dipladenia, make good spillers in full sun. There are several colors available and they don’t have to be deadheaded as ivy geraniums often do.Oregano Kent Beauty is the perfect spiller for a window box that’s filled with herbs.
Fillers
There are numerous begonias that are perfect fillers for shady pots and boxes. Browallia comes in purple or white and is an ideal filler for shady containers. This on e is Endless Illumination from Proven winners.Solenia begonias are useful for boxes because they do well in sun or shade. They are the perfect fillers for situations where some of the boxes are in shade while others get more sun.Pentas make good fillers in sunny window boxes. They come in several colors and their flowers attract butterflies.Many view Diamond Frost Euphorbia as being their “secret weapon” in a container. It flowers all summer and knits the other plants together in a lacy kind of way.Nasturtiums that are a bush form, not a vining type, are good fillers and work well in boxes that contain herbs. The leaves are cheerful, the flowers are bright, and both are edible.
Thrillers
Purple Oxalis is a good filler for containers in shade. You get the pretty foliage and pink or white flowers as well.Dranta Gold Edge is a good thriller in part-sun to part-shade containers.Dentata ‘Little Ruby’ adds colorful foliage that just becomes more vibrant as the summer goes on. Use this when a pot or a box is in full sun.Silver curry plant (one of the Helichrysum varieties) adds a touch of drama to containers in full sun. The foliage smells like curry, but it is not used in cooking and is not the “curry leaf” called for in recipes. Use this for foliage contrast only. Silver plants look especially good with purple-leafed plants and pink flowers.
Don’t be afraid to pack in plants in a window box – the season is short, and it’s fun to have them looking spectacular from day one. Be sure to have drainage holes in your boxes, and use new potting mix every summer.
