Your cart is currently empty!
How to create an outdoor container display for summer | ‘Thriller, filler, spiller’ formula
How to create an outdoor container display for summer | ‘Thriller, filler, spiller’ formula
The ‘thriller, filler and spiller’ formula: A guide for creating an outdoor pot display for summer. — with Elly Keen (@daydream.green)
The 2025 Spring Gardening Series is supported by Gubba Garden Store.
It’s that time in the garden when your early spring crops are coming to an end. As the season goes on and the weather warms, you’ll notice that bulbs, like daffodils, tulips or ranunculus will be yellowing — signalling the end of their lifecycle for another year.
If you haven’t already, take this opportunity to fertilise your spent bulbs with an organic product that contains phosphorus. The bulb stores its energy for next year’s flowers through its leaves so allowing these to yellow and die back naturally is an important part of its process.
It’s also time to create a new outdoor pot display for the summer months…
How to create an outdoor container display for summer
Choose the right pot or container
Don’t skimp on size here – the bigger the better. This really makes all the difference come summertime when rainfall is low and water restrictions come into play. Pots or containers need more watering over the summer months, so choosing something at least 30cm x 30cm is recommended.
Or get creative with a Greenstalk vertical planter from Gubba (discount code here).
Soil matters
On first inspection the soil might look ok, but it is so important to refresh your soil mix prior to planting.
Potting mix generally has a shelf life of around 3 months (unless specified) so grab a new bag of potting mix or add some compost / worm castings to inoculate microbiology back into a soil that would have been leached of nutrients over the spring period.
Further reading: A simple guide to soil mixes & amendments
Retain moisture
As noted, pots have a tendency to dry out over the summer months. One option is to use a wetting agent in the pot to keep the soil moist and lessen the need to water. Watergel water storing crystals can be handy as they can last for several years, and are also an organic product that biodegrades harmlessly.
Plant selection
Now you’ve dealt with all the boring bits, it’s time for the fun part. Plant selection! Not all plants are suitable for pots, and it’s important to consider the shape and size before planting. But a container display is a chance to be a little creative and have some fun!
When it comes to plant selection, consider the ‘thriller, filler and spiller’ formula. This method will help you to create pot displays that are multi-layered, with interesting texture, form and pattern.
The ‘thriller, filler & spiller’ formula
Thriller
Thriller plants are tall plants that will provide height in the pot. They are generally the star of the show and bring a bit of drama. These plants add some structure and form.
Examples of thriller plants for pots include dahlias, salvia, Verbena bonariensis or ornamental grasses such as Miscanthus sinensis ‘Morning Light’ and Calamagrostis ‘Karl Foerster’
Filler
Filler plants are usually very leafy, and they provide depth, contrasting colour and texture. They are generally mid height and add bulk to the design.
Examples of filler plants for pots include begonias, pelargoniums, petunias, heucheras or lamb’s ear.
Spiller
The spiller category includes cascading plants that trail down over the edges of the pot. They help to soften and naturalise the design by hiding the container.
Examples of spiller plants for pots include bacopa, nasturtium, phlox, alyssum, Cranesbill geranium or thyme.
Position and layout
Once you have selected your plants, it’s time to fill the pots. The thriller plant will be positioned directly in the middle, followed by filler plants as the second layer and at the outer edges of the pot goes the spiller varieties.
Caring for your pots
Feed and mulch
Always finish off with a drink of seaweed solution to lessen transplant shock, and mulch with a bit of compost to help retain moisture. A handful of sheep pellets or organic slow-release fertiliser will keep your pots looking happy over the summer months.
—
While it is sad to say goodbye to our early spring flowering bulbs, a switch to warmer weather means we can now enjoy many of our beloved summer flowering annuals and perennials.
A quick refresh of soil and other prep now will give your pot display lasting power throughout the hotter days ahead. While the ‘thriller, filler, spiller’ formula will guide you when selecting the right plants to create an interesting and well-balanced display.
The Spring Gardening Series is proudly supported by Gubba Garden Store.
www.gubba.co.nz | @gubbagardenstorenz
