And I’ve got to say, not every flowering plant is a good candidate for a window box. Think about how narrow and petite the typical window box is (often 8 to 12 inches wide and equally shallow) not a lot of room especially if you have roots that want to spread long and grow deep:-)
Flowering plants come in all shapes and sizes, yet the root confining nature of window boxes calls for just the right tenants for a win win window. Keep in mind that you’ll want to give additional TLC. For example, unless you have an automatic watering system, You ARE chief waterer. On days that are HOT, you’ll need to water daily, possibly more. Great quality, moisture retentive, potting soil is also a must. Coconut coir or peat moss are two important moisture retentive ingredients, along with candidates like perlite, vermiculite, etc. Choose a well formulated potting soil mix that includes one or more of these ingredients.
But back to the answer. I’m a fan of perennials overall. So this list of eleven includes flowering plants that are perennials where I live, USDA zone 10, but may very well be annuals where you live. If I had to pick my favorite of those below, it would have to be ivy geranium. Specifically, the single flowered ones you see trailing and festooning from window boxes and hanging baskets all over France and Europe 🙂
Top Flowers Choices for your Window Box
1. Bidens – This is a short lived yellow flowering perennial with a trailing habit. It enjoys full sun and moderate water; and will flower profusely.
2. Bacopa – This is a very adaptable flowering perennial for part shade, and it comes in the ever popular white and lavender.
3. Calibracoa – (Check out hybrid: Superbells.) This plant requires no deadheading just enjoy its small petunia-like flowers all season on cascading/trailing growth. It’s available in colors: gold, purple, pink and white. This fast growing, strong bloomer likes sun & well drained soil, a must.
4. Ivy Geranium – (Pelargonium peltatum = Ivy geraniums.) I love the single flowered ones like: ‘White Blizzard’ – ‘Dark Red Blizzard.’ There are a lot of semi-double beautiful choices available too!
5. Zonal Geranium –
8. Petunia Supertunia – (Supertunia: This is a vigorous series) with bright flowers in magenta, red, blue purple, bubble gum pink that is ever-blooming and long-lived. Blooms are fragrant and growth is trailiing. This is considered a perennial where climates are mild.
9. Scaevola ‘New Wonder’ – Eye-catching fan shaped flowers; this fast growing plant is great for hot, humid areas and it’s quite heat tolerant. Plant in sun to part shade. It likes moist soil. Add coconut coir to your potting soil for better moisture retention if needed.
10. Verbena hybrid (Temari and Tapien)–
11. Viola ‘Freckles’
ps: Always wanted a window/deck planter? If you have space along a window or deck (and water runoff is not an issue), there are many great, easy to install planter choices online. Two good options are the flat iron planters with a coco coir liner or the more lightweight, plastic planters made to look like terra cotta.