Best Flowers for Window Boxes That Bloom All Season

Every spring, I find myself dreaming about colorful window boxes overflowing with blooms.

There’s just something about looking out the window and seeing a burst of color that makes life feel lighter.

When I first tried planting my own, though, I picked flowers that fizzled out after a few weeks.

That’s when I learned the secret: you’ve got to choose flowers that can handle the heat, bounce back after rain, and just keep going all season long.

I’m writing this to help you skip the trial-and-error stage.

You’ll find flowers here that I’ve grown myself and loved—or watched neighbors have amazing luck with.

If you want window boxes that stay bright and beautiful from spring through early fall, this guide’s got you covered.

1. Petunias

Petunias are the classic choice for a reason.

They bloom like crazy, come in almost every color, and love the sun.

Deadheading (pinching off spent blooms) keeps them even fuller.

2. Geraniums

Geraniums bring bold color and handle tough conditions like champs.

They prefer lots of sun but can tolerate a little shade too.

I love their almost rubbery leaves—they smell amazing when you brush against them.

3. Calibrachoa (Million Bells)

Calibrachoa looks like mini petunias and blooms non-stop.

They spill beautifully over the sides of window boxes.

Plus, they’re low-maintenance if you keep them watered.

4. Lobelia

Lobelia’s small, delicate flowers add a soft texture to your arrangements.

The sky-blue or deep purple varieties are especially stunning.

They thrive best in cooler temperatures but can survive summer heat with a little care.

5. Begonias

Begonias are perfect if your window box gets partial shade.

They bloom heavily and don’t need a lot of fussing.

Their thick, waxy leaves help them survive even on hot days.

6. Sweet Alyssum

Sweet Alyssum creates a lovely, fragrant carpet of tiny white or purple flowers.

It spills gently over the edges and fills in gaps between bigger plants.

It also attracts pollinators like bees and butterflies.

7. Impatiens

If your window box is shaded most of the day, impatiens are a must.

They bring bright color without needing full sun.

Just keep them watered—they hate drying out.

8. Verbena

Verbena blooms through heat, drought, and just about anything else.

The trailing varieties look especially beautiful spilling down from boxes.

A little trimming in midsummer keeps them looking fresh.

9. Nasturtiums

Nasturtiums give you bold, tropical-looking flowers plus pretty round leaves.

They love full sun and don’t mind poor soil.

Bonus: their flowers are edible and peppery, great for salads.

10. Marigolds

Marigolds bring that pop of gold, orange, and red that just screams summer.

They’re super tough and even help repel pests like mosquitoes.

Deadheading keeps them lush and full until the first frost.

11. Bacopa

Bacopa’s trailing white or lavender blooms add a soft, airy touch.

They love sun but can handle part shade too.

Keep the soil moist to keep them happy through hot spells.

12. Salvia

Salvia’s spiky blooms add vertical interest to any arrangement.

They thrive on heat and dry conditions, making them almost effortless.

Hummingbirds love them too, which makes the view even sweeter.

13. Zinnias

Zinnias are all about bright color and non-stop blooms.

They’re drought-tolerant and don’t mind intense sun.

Just give them a little deadheading and they’ll reward you with flowers all summer.

14. Fuchsia

If your window box gets morning sun and afternoon shade, fuchsia is a great pick.

Their exotic-looking blooms dangle down beautifully.

They do need regular watering, but the show they put on is worth it.

15. Dusty Miller

Dusty Miller isn’t technically grown for flowers but for its soft, silvery leaves.

It adds a beautiful contrast against more colorful plants.

Plus, it’s tough, heat-tolerant, and drought-resistant.