These simple formulas for filling out window boxes will have you itching to plant your own.

Sweeping Vines Window Box Trio
Jen Stringer Obi designed this stop- and-stare sight. A trio of boxes filled with white caladiums, red ti plants, and dramatic swags of creeping Jenny and ivy enlivens the facade of this historic home. Designer Tip: "Start with a well-draining potting soil–you don't want to use anything too heavy. Don't plant in topsoil, as it will rot your plants out."—Jen Stringer Obi
| Credit: Hector Sanchez

Window boxes are a no-fail way to add immediate curb appeal to your home. And there's something about those lush, colorful planters that give your house a major dose of southern charm. Just take a look at the Instagram posts shared with #windowboxwednesday and you'll find endless inspiration for unique combinations of color and texture—and you'll realize that you can always count on Charleston to have gorgeous window boxes on every block.

Filling up only a small container, window boxes are a mini-garden of sorts that anyone can handle. And mastering the art of picking and arranging the plants inside is easier than you may think. If you don't already know it, the not-so-secret formula for a well-proportioned and beautiful window box arrangement is a combination of thrillers, spillers, and fillers. Thrillers are your statement-makers, typically a tall and large plant (like leafy caladiums or evergreen shrubs) that adds vertical interest and drama to your window box—plus you can usually see these plants from indoors as well, an added perk. Spillers will also add vertical interest to your window box, but in the opposite direction. Smaller trailing plants like ivy or jasmine will cascade over the edge of your box, taking advantage of the height off the ground. Finally, your fillers will add in color and texture, taking up the box-level real estate. Think: pansies, mums, snapdragons, and even kale or cabbage.

WATCH: How To Plant A Window Box

If you're ready to mount some mini-gardens under your windows, here are 5 easy window box recipes that will be sure to add some lively, colorful beauty to the outside of your home all year round.

Make It Interesting
Credit: Photo: Van Chaplin, Window Box Design: Tracee Lund

A classic combination of leafy greens accented with punches of pink and purple is the perfect way to usher in spring.

In this box: Pink geraniums pull double-duty with leafy green stems filling out the box and large, tall blooms bringing in height and color. They're perfectly paired with large-leafed Pink Beauty caladiums, while purple petunias spill over the sides.

Versatile Outdoor Plant Container
Mix mums with lush greenery for a container bursting with colorful blooms and textural foliage.
| Credit: Hector Sanchez

The mums in this arrangement can be swapped for other flowers during different seasons, but this color palette is perfect for leading into fall.

In this box: Mums and tropical croton take center-stage in this planter, with always-popular sweet potato vine filling in the box and spilling over. Texture-rich Angelina sedum fills in at the sides.

Tropical Window Box
This window box by Kelli Shaw illustrates her characteristically bold and unexpected design approach. A red-centered, starlike bromeliad appears to burst from the box. And red-stemmed caladiums echo that color. In contrast, spiky maroon cordyline, deep purple heuchera, pink begonias, and trailing 'Outback Sunset' golden globes fill out this arresting showpiece. Designer Tip: "Plants need to be watered before they're planted. Water them while they're in the little plastic pots. Don't put a bunch of dry plants in a box and then try to water it—the water will just roll around the dry root ball and never wet it." —Kelli Shaw
| Credit: Hector Sanchez

Contrary to what you might think, window boxes don't need to be flower-dominant and they certainly don't need to be symmetrical, as this stunning tropical-leaning arrangement shows. Paired with the navy window box and shutters, these vibrant tones of red and green really pop against the creamy exterior of this house.

In this box: A large red-centered bromeliad and red-stemmed caladiums are the thrilling show-stoppers in this box, accented with trailing golden globes. Purple heuchera and pink begonias provide the filler.

Zinnia Container Garden
Credit: Robbie Caponetto

You don't necessarily have to incorporate a lot of variety into your window boxes if you prefer a more consistent look. Just be sure to pick a plant that you can count on to bloom and properly fill your container—you won't have any backup if your singular star disappoints.

In this box: Zinnias are an easy sun-loving summer flower that will give you a variety of color and lush, full blooms. Plus, they do best when you regularly trim them, so you'll have bright arrangements indoors as well. Pair them with a simple vine or ivy like Asiatic jasmine or creeping jenny so you still have a contrasting green spiller cascading over the edges.

Color with Kale
Credit: Photo: Ralph Anderson

You don't have to worry about withering window boxes during the colder months of the year if you plan accordingly. Evergreen shrubs are ideal year-round thrillers, and when summer blooms start to fade, switch them out for ornamental kale or cabbage for full and colorful boxes throughout fall and winter.

In this box: Nagoya and Peacock kale thrive during cooler months—the frost brings out their rich colors. Fragrant lemon cypress shrubs add height and texture, accented by purple violas.

Looking for more inspiring combinations? Check out our most creative container gardens—many of which can easily work in a charming window box.