How to Create Stunning Container Gardens

The Thriller, Filler, Spiller Framework for Container Gardening Ensures Success

Thomas here!

Creating stunning container gardens is as simple as remembering three words: Thriller, Filler, Spiller. This proven gardening formula ensures your pots and planters look lush, balanced, and visually appealing, no matter your style. By understanding each component, you can confidently choose plants at your local nursery to create a personalized masterpiece. (Paid subscribers make sure to access my spreadsheet of top container plants by light and moisture requirement at the bottom of this post.)

Understanding the Thriller, Filler, Spiller Concept

• Thriller: This is your focal point—a plant that’s tall, bold, and eye-catching. Thrillers add height, drama, and a central anchor to your design. Examples: Ornamental grasses, Boxwood topiaries, small trees like Japanese maples or olive trees.

• Filler: These plants surround your thriller, adding fullness, color, texture, and visual interest without overshadowing the central focus. Examples: Begonias, geraniums, lavender, salvia, culinary herbs.

• Spiller: These plants cascade over the edges, softening the container’s lines and adding elegance. Examples: Creeping Jenny, ivy, sweet potato vine, trailing rosemary.

Selecting the Right Container

Choosing the correct pot size is essential. A general rule of thumb is to select a pot at least 12 inches in diameter but 18-24 inches is preferred for this method, allowing adequate room for root growth and visual impact. Bigger containers reduce watering frequency and give your plants a healthier environment.

Plant Quantity and Spacing

For balance and visual impact, follow this guideline for an average-sized container:

• Thriller: Typically 1 plant per container.

• Filler: 2-4 plants depending on the pot size.

• Spiller: 2-3 plants to cascade around the container evenly.

Ensure plants have about 2-4 inches of spacing between them initially. This allows growth room while ensuring the container looks full from the start.

When NOT to Use This Method

The Thriller-Filler-Spiller approach is excellent for creating three-dimensional impact and structure. However, it may not suit minimalistic designs or succulent arrangements, where uniformity and simplicity are key.

Inspiring Combinations to Try

Here’s some inspiration images as well as some specific examples you could make.

1. Culinary Herb Garden:

   • Thriller: Upright rosemary

   • Filler: Basil, parsley

   • Spiller: Thyme, oregano

2. Classic Boxwood Container (great for shadier area like front porch):

   • Thriller: Boxwood topiary

   • Filler: White impatiens

   • Spiller: English ivy or creeping Jenny

3. Mediterranean Olive Container:

   • Thriller: Dwarf olive tree

   • Filler: Lavender, sage

   • Spiller: Trailing rosemary, oregano

4. Elegant Window Box:

   • Thriller: Geraniums or dwarf grasses

   • Filler: Bacopa, petunias

   • Spiller: Variegated ivy or calibrachoa

Dual-Purpose Plants: Fillers & Spillers

Certain versatile plants can beautifully perform as both fillers and spillers, especially useful in smaller containers or window boxes. Some examples include:

• Sweet Alyssum (my absolute favorite): Dense blooms, fragrant, trails gently over edges while filling gaps.

• Calibrachoa (Million Bells): Continuous blooms, compact growth fills spaces while trailing gracefully.

• Bacopa: Soft, airy texture; creates lushness within and around containers.

• Trailing Petunias: Rich, continuous color; fills spaces densely and spills beautifully.

• Verbena (Trailing varieties): Abundant blooms that both fill gaps and cascade elegantly.

Watering Tips for Large Containers

Drip irrigation systems are the most reliable way to keep large containers hydrated. But if drip irrigation isn’t feasible:

• Self-watering Containers: Built-in reservoirs provide a steady moisture supply.

• Moisture-retaining Crystals: Mix into the soil to retain moisture longer.

Fertilizing, Feeding, and Deadheading

• Fertilizing: Feed containers every 4-6 weeks using a balanced, slow-release granular fertilizer or liquid feed bi-weekly during growing seasons.

• Deadheading: Regularly remove spent flowers to promote continuous blooming and maintain a tidy appearance.

By following these simple guidelines, you can confidently create and care for stunning containers suited perfectly to your style and space. Happy gardening!

Want Even More Container Gardening Guidance?
We've created a comprehensive Google spreadsheet of the Top (and most commonly available) Container Plants by Light, Moisture, and Design Role (Thriller, Filler, Spiller). Use this to plan your containers using our meticulously curated plant database, saving you time and money at the nursery. This valuable gardening tool is exclusively available for our paid subscribers—a special thank-you for your continued support.