But there is a utility as well as creative aspect to gardening in window boxes, as there is in all containers. Window containers, by definition, are restricted in size, width and depth. This makes them, especially in our dry-summer climate, very, very thirsty. You would do well, when prepping your window boxes, to rig some kind of irrigation, whether it be drip lines, soaker hoses or just placement near a spigot or faucet. For it is not unheard of to have to water every single dang morning. Potting soil embedded with water-retentive polymers also helps.
If you have, or are building, a wooden window box, keep in mind that this much-needed water, while nourishing your plants, is also slowly destroying your planter. To counter that, insert galvanized or even plastic liners to plant in.
Just as these liners have drain holes at the bottom (so roots don't rot), so should your window box (so the box itself doesn't do the same). For aesthetics, your window box should be about the length of the window. But you knew that. Ten inches wide and 8 inches deep is about the minimum. It can get cramped in there. And when placing this crate, for goodness sake make sure you can open your window - and open it without decapitating your flowers.
When considering flowers for your window box, some things are out of your hands. Is your box completely shaded? Then no cheery little roses for you. Do reflective white walls and overhanging eaves act like an Easy-Bake Oven? No sun-shy hostas here, ma'am. And as much as the garden world still stands agog over the use of flowering perennials, you will probably want to stick with mostly annuals in your window boxes. The not-all-that-many perennials that are accorded the adjective "long-blooming" still measure their bloom time in weeks. Annuals, however, tend to bloom themselves silly all season long. Foliage plants, of course, do yeoman duty for as long as you need them. Remember: Flowers are fleeting, but foliage is forever.
More window box tips- Use plants of differing heights, texture and character, just as you do in your garden proper. Think: spillers, fillers and thrillers.
- If you happen to have boxes so large or deep that weight might be an issue, put down a bottom layer of plastic packing peanuts or a new product call Packing Pearls to take up space. (Careful: Those biodegradable peanuts made from cornstarch turn to a cloggy mess when wet.) You can also invert a row of small garden or nursery pots under the soil.
- If you can't find a liner that fits your box, you can always insert a row of regular containers. Might even want to camouflage this fact by obscuring the edges of the pots with moss. Also, if you keep backup planted pots at the ready, you can slip out containers of faded or scorched plants and pop in a fresh pot presto-change-o.
- Fuchsias: a showy, romantic spiller.
Magnificent window box plants for shade
- Ferns: especially the Japanese Painted ones that come in so many colors.
- Hostas: so many sizes and colors - even twin tones - to choose from.
- Ivy: variegation is the spice of life.
- Begonias: now ranging from squatty to towering.
- Coleus: pick a color. Any color.
- Margarita potato vine: really lights up the shade.
- Helichrysum: a silver-gray or chartreuse cascade.
Magnificent window box plants for sun
- Phormium: great architectural accents.
- Lobelia: especially the little trailers in varying shades of blue.
- Alyssum: a bulletproof waterfall in white, pink or purple.
- Miniature roses: but give them some room.
- Artemisia: it's not invasive if it's in a pot.
- Blackie sweet potato vine: exquisite dark foliage.
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