The 40 Best Flowers and Plants for Gorgeous, Thriving Window Boxes

When you want to elevate your home's charm and curb appeal, plant a window box. Attach one or more under your windows, use them on a porch or deck railing or mount them on a wall, fence or gate. They're beautiful whether they're filled with showy blooms, vibrant foliage or a colorful combination of plants, and you can grow bulbs, annuals, perennials, ornamental grasses, small conifers and herbs -- almost anything goes. There aren't any hard-and-fast rules, but our tips will help you find the best plants for window boxes and know how to take care of them.

How to Select the Window Boxes

Start by choosing the best window box planters for your exterior style. It's easy to add window boxes; drill some holes in them for drainage, if they don't have a way for water to escape, and fill them with fresh potting soil. Bagged soil with a slow-release fertilizer will get your plants off to a good start.

How To Choose the Right Plants for Your Window Box

As a rule of thumb, the best plants for window boxes, whether they're flowers or foliage for sun or shade, will...

• Have shallow or compact root systems. This way they can thrive in relatively small containers
• Be somewhat heat and drought-tolerant. Window boxes, especially if they're made of wood, heat up faster and dry out quicker than garden beds and borders)
• Not need to be deadheaded. If your window box is hard to reach, trimming, pruning or cutting back your plants won't be easy, so consider flowering plants that are self-cleaning (that is, they shed their old blooms naturally).
• Rebloom for a long time. This way, you won't have to replace them very often.

Pair Plants with Similar Sun and Water Needs

Decide whether the window planter box will get sun or shade, so you can pair sun-lovers with other sun-lovers, and shade-seekers with plants that like shade. Choose plants that have the same basic requirements for water, too, so you won't drown drought-tolerant plants or let thirsty ones get overly dry.

Refresh Plants Based on the Season

Annuals live for a single growing season, while perennials that are cold-hardy in your USDA Gardening Zone can come back for years. Try refreshing your plants when the calendar changes.

In spring: look for early-flowering bulbs, perennials and cold-hardy annuals, ornamental grasses, herbs and edibles like leafy greens.

In summer: replace finished spring plants with warm-season plants or edibles like Tomato Kitchen Minis® 'Red Velvet'.

In the fall: grow mums, asters and other plants in autumnal colors. As winter approaches, select cold-hardy plants. Chuck Pavlich, Director of New Product Development for Terra Nova Nurseries, recommends plants like coral bells (Heuchera) ‘Green Spice’ or ‘Red Lightning,' for example, for the dramatic red veins they show off in cold temperatures. If your winter window box is empty, or the plants go dormant, use it as "a base for holiday arrangements of boughs, holly, bows and plastic ornaments," Chuck says.

Plan Your Window Box Layout

Many gardeners use a layout of thrillers, spillers and fillers. Thrillers are tall window planter box plants. Spillers are flowers or foliage plants that trail or tumble gracefully over the sides. Fillers are often rounded or mounded plants used to help fill up the box.

Keep small window boxes simple; plants in the same color or a few colors are enough. In boxes of any size, put tall plants on the sides to frame your window and avoid blocking the view, or at the back, behind shorter ones. Chuck says plants that are all the same height can make a box look boring, while different heights and textures add interest. Find window box design ideas here.

The 20 Best Flowers for Window Boxes

Annuals Vs. Perennials for Continuous Blooms

Few perennials bloom all year, but you can use perennials or other plants with staggered bloom times to keep the flower show going. Many gardeners add annuals to their window boxes with their perennials or when the perennials finish.

Creating Color Schemes with Flowers

Window boxes planted with just one or two kinds of plants can make a big impact. "I really love mixed window boxes but sometimes a clean mono-planting of one variety can have a very polished and elegant look," says Marcus Jansen, Product Development Manager for PanAmerican Seed.

Window planter box plants can complement the exterior colors of your home or contrast with it. Go neutral with green and white and add one more color to make a special plant pop. Plant a window box using these stunning summer "recipes" or play with colors to find your favorites. Art supply shops and other stores carry inexpensive color wheels to help you match or contrast colors.

Best Flowers for Shady Window Boxes

• Begonia such as Dragon Wing® Begonia
• Fuchsia
• Pansy
• Johnny-Jump-Up
• Wishbone flower (Torenia)
• Impatiens such as Beacon® Impatiens 'Lipstick'
• Hellebore (Lenten rose)
• Geum
• Browallia
• Nepeta

Best Flowers for Sunny Window Boxes

• Petunia
• Geranium
• Lantana
• Zinnia
• Verbena
• Salvia
• Scaevola
• Calibrachoa
• Angelonia such as Serena Mixture
• Vinca such as Titan-ium™ Vinca

The 20 Best Foliage Plants for Window Boxes

Incorporating Foliage for Texture and Interest

Textured foliage plants, used by themselves or mixed with flowers, make your window boxes more visually interesting. Choices for texture include fine-cut Maidenhair or asparagus ferns, ornamental grasses, sweet alyssum, big-leaved hostas and coral bells with ruffled leaves.

Use Trailing Plants for Dramatic Effects

Plants that trail soften the edges of window boxes, help them look lush and full and add a sense of depth and movement. "I like to utilize double-spilling layers in a window box," says Marcus, who grows trailing Dichondra underneath spreading Wave® Petunias. Try creeping Jenny, trailing Lobelia, nasturtium, trailing pansies, cascading petunias, ivy, sweet potato vines and licorice plants.

Foliage Plants for Shady Window Boxes

• Coleus such as 'Kong Jr.'™ coleus
• Hosta
• Ajuga
• Fern such as FuzzyFern™ Frizz Asparagus
• Caladium
• Mint
• Ornamental peppers
• Carex ornamental grass
• Coral bells (Heuchera)
• Inch plant (Tradescantia zebrina)

Best Foliage Plants for Sunny Window Boxes

• Croton
• Lamb's ear
• Dusty miller
• Sedum
• Dwarf fountain grass (Pennisetum)
• Sun-tolerant hostas and coleus
• Japanese Sweet Flag (Acorus gramineus 'Ogon')
• Sweet potato vine
• Licorice plant
• Little Bluestem (Schizachyrium scoparium)

How to Care for Your Window Box Plants

Watering Tips for Container Plants

Some window box planters are self-watering or have built-in irrigation systems. If you're doing the watering, apply water to the base of the plants and keep it off the foliage to help prevent disease. Add water until it drains out of the bottom of the box. Small or shallow boxes tend to dry out fast, so you may need to water once or twice a day. It's usually time to water if you put your finger about an inch deep in the soil and it feels dry.

Fertilizing for Optimal Growth

Mix a granular slow-release fertilizer into the potting soil when you plant, or use a potting soil that already has it in it. You'll probably need to add a balanced, water-soluble liquid fertilizer designed for container plants weekly, in the amount indicated on your product's label. Apply it as often as indicated, too.

Pest Management Strategies for Healthy Plants

The best strategy is to keep your plants healthy in the first place, by watering and fertilizing properly and giving them the right amount of sun. If needed, use neem oil, insecticidal soap or other natural controls to target only the pests on your plants; avoid products that kill indiscriminately, so you don't harm beneficial insects. Remove dead or diseased plants or plant parts as soon as you see them, so problems don't spread. For big pests--think squirrels or birds--you may need to put netting over your plants or insert plastic or stainless steel spikes into the soil.