Flower gardening in containers

On my pursuit for a rambling floral backyard, I have become an accidental container gardener.

I’m lucky to have a generously-sized urban Christchurch plot and equally lucky to have mature trees and high fences which create quite the haven. However, these also provide enough shade to be problematic for my flower-growing goals and once I understood the life-giving powers of direct sunlight, I had to set a new course.

a variety of containers catching the sun for me at home.

After much observing, I pinpointed sun-drenched zones in the paved areas around my back porch and began construction on what has come to be known as “pot city”.
Like all developments, pot city started slow, made up of mostly affordable, small pots gathered along the way from hardware stores and secondhand shops. We cut our teeth on “containing” trees with the experimental transfer of a dwarf Japanese maple into a ¾ wine barrel – a successful test given that it is still thriving four years on. Soon we added a potted ball topiary, a limequat tree, a bay tree and a series of short troughs under the living room window planted up with shasta daisies, geraniums and pansies.

A japanese maple in a wine barrel, limequat and topiered teuchrium that has been since replaced with a topiered bay tree.

But the real turning point was the success of growing dahlias in two home-built, trough-style containers made of wood and lined with plastic. I had essentially achieved my wished-for dahlia border on concrete and the beautiful display made me hungry for more.
Buoyed by this success, in 2020 pot city moved into a major expansion phase with a couple of wine barrels being cut into planters of differing heights, painted internally with a waterproofer and made mobile with three heavy-duty castors on the bottom. These were then planted up with a dwarf apple tree, itself underplanted with nemesia and chives. Another was filled with four varieties of dahlias, while the other two housed a hybrid tea rose called “Blue Moon” and I piled echinacea, rudbeckia and verbena bonariensis into the last.

Essentially, I was leaving behind my polite, pot-appropriate planting for the big, bold, bossy flowering plants I love in gardens. In a collection of my favourite lightweight pots from my local Mitre 10, I planted a tall, architectural stand of verbena bonariensis and verbena rigida, paired with dustbin plantings of equally airy sanguisorba officinalis.
With my dahlias graduated to other pots to stand over their garden planted cousins, I did away with our home-made planters and replaced them with two very large but lightweight concrete troughs I won on Trade Me. In these, aiming for the same vibe as a tall romantic garden border, I transplanted bog sage along the back with poppies and nigella spilling at the front edges.

All in all, pot city really has thrived this growing season but not without daily check ins, which is a real pleasure when you see your planting spring to life.

Dahlias in the garden flanked by pots on the patio to create a lush banked vibe!

Some keys to container-based flower growing that I have learned along the way:

Be diligent at watering

The smaller the pot the more often you will need to water it during the summer. So when you have the chance, scale up.

During the summer months, I monitor my containers on a daily basis, taking into account the weather, recent rain and physically sticking my finger into the soil to hunt for moisture if I am unsure. When it is very hot and sunny you may be watering daily.

The trick is to water only either early or late in the day to avoid evaporation and to really soak them, gently applying water until you see a good trickle coming out the bottom. For my pot city, hand-watering by hose with a good nozzle takes an hour – but nothing good comes without effort.

Mix containers

To create that abundant vibe that a garden bed can give, look to mix pot heights and shapes. I love nothing more than to “bank” them, scattering shorter pots in front of the taller ones.

Let your planting do the talking and keep your pots pretty neutral in colour, helping them act as the solid structure within your scheme. I stick to a loose palette of terracotta, greys and the wooden wine barrels and steer clear of patterns or brights.

Containers of perennials to bring great joy during summer months

Poppies that happen in late spring in front of bog sage that comes into its own in late summer/autumn.

Verbena bonariensis and verbena rigida in a tall pot beside sanguisorba offinalis in a dustbin and shasta daisies and paper daisies below the window.

Use quality potting mix

Give yourself the best chance of success by spending your hard-earned cash on quality, outdoor container-specific potting mix. This makes a huge difference to healthy plants going forward and especially with trees that aren’t easy to whip out and freshen up. Ask at your garden centre if you are unsure of your options.

Be bold

In the last few years, I have skipped the research on what was “best suited to pots”, instead choosing to grow what was “best for my eyes”. The resulting chorus has surprised many, including myself, with great successes with tall growing perennials and a real spotlight on my thriving wine barrel rose.
I pursued mostly summer-flowering perennials, focusing on wonderful colour and floral forms.
I love the tall and architectural forms waving at me across the broad green leaves and velvety blooms of others. For your own mini pot city to deliver on the garden vibe, variation in planting is vital.

Mixing plants of different heights and varieties within a single container really gives bang for my buck.

“Blue moon” rose very happily living in a wine barrel.

Consider the seasons

Although this is an area in which I’m still dragging my feet, pots offer a brilliant way to bring spring brightness to your space by underplanting perennials and annuals with tulips and daffodils.
here is a terrific book that will really get your ideas going called The Pottery Gardener by young UK gardener Arthur Parkinson. He shows what total joy can be delivered with potted planting and breaks down ideas on seasonal succession planting for a long display.

Plant evergreen as well

Just like in your flower garden, a little evergreen structure goes a long way to maintain interest during the wintery downtime. My potted bay, topiaried ball and limequat really assist with this as does my large hebe which I have sitting, potted up amongst my stand of Japanese anemones in the garden.
Once again, watering is your key to success here closely followed by regular offerings of plant food to top up the depleted potting mix after a year or so.

Whether container gardening offers you freedom as a renter or is the best option for a tight space, rest assured that you truly can achieve your own wild refuge to be sat in or cut from to take inside.

This article was first featured in my Stuff ‘Homed’ gardening column for beginners and The Press on February 18 2021
All words and images are my own, shot in my garden in Christchurch, New Zealand.