I finally got around to adding a window box planter to my home this spring—and I immediately fell down the rabbit hole of researching how to fill it and what flowers to use. While there are plenty of great planter guides out there, I noticed very few focused specifically on cottage style flowers—and that’s exactly the look I wanted to create.
So, I put together this post to walk you through everything I learned:
- How to fill your planter based on box size
- What types of flowers to choose for that dreamy European cottage style vibe
- A peek at the exact combo I used (and how it turned out!)
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Planter Box Sizing Guide: How Many Plants You’ll Need
Here’s a simple rule of thumb using the thriller, filler, spiller method:
- 24″ Box: 1 thriller, 2 fillers, 2 spillers
- 30″ Box: 1-2 thrillers, 2-3 fillers, 2-3 spillers
- 36″ Box: 2 thrillers, 3 fillers, 3 spillers
- 48″ Box: 2-3 thrillers, 4-5 fillers, 4-5 spillers
I absolutely adore the window planter I bought—it’s vintage-inspired, made of iron, and gives total countryside charm. You can shop the same or similar styles here! They also carry the cutest cottage garden décor!
Cottage Garden Flower Recommendations
These are my favorite thrillers, fillers, and spillers for a romantic, overflowing look:
Thrillers:
- Foxglove 🌞/⛅
- Delphinium 🌞/⛅
- Snapdragon 🌞
- Salvia 🌞/⛅
- Lavender 🌞
- Veronica Spicata 🌞
- Agastache (Hyssop) 🌞
Fillers:
- Geraniums (Zonal or Ivy) 🌞
- Pansies or Violas 🌞
- Million Bells 🌞
- Alyssum 🌞
- Daisies 🌞/⛅
- Dusty Miller 🌞
- Dianthus 🌞
- Nemesia 🌞
- Scabiosa 🌞
- Miniature Roses 🌞
- Petunias 🌞
Spillers
- Creeping Jenny 🌞
- Orange Eye (Thunbergia) 🌞/⛅
- Vinca Major 🌞
- English Ivy 🌞
- Sweet Potato Vine 🌞
- Bacopa 🌞
- Lobelia (trailing) 🌞
- Trailing Verbena 🌞
- Trailing Rosemary 🌞
- Scented Herbs 🌞
My Window Box Planter
What I used in my 40″ planter box: 3 thrillers (Salvia – Hot Lips), 4 fillers (two pink petunias, and two daisies), and 4 spillers (two orange eye and two vinca major). I went with the color scheme of whites, and pinks with a little green from the vinca major – it turned out so cute, the perfect cottage style I was going for!! The pictures below only represent about 5 weeks apart – the growth is crazy, and looks so beautiful!
If you’re craving that cottagecore curb appeal, a thoughtfully planted window box is such a simple way to make a big visual impact. Let me know if you try any of these combos—I’d love to see your version! 😍
