Over the past two years, I have accumulated a little collection of terracotta pots in a sheltered corner of the Garden Museum in London, where I am head gardener. The largest is no wider than 30cm (12in), the smallest the size of my hand. They allow me to trial plants I haven’t grown before, and together form an uplifting, colourful display. Through spring they have bulged with yellow uvularias, bright dicentras and the tubular blooms of corydalis. Most enjoyable is the ease of maintenance: I can water by hand, feed as necessary and rearrange to my heart’s content.
With spring now almost over, I’m transferring these plants to suitable homes throughout the garden and preparing to refill the pots. Like many gardeners in lockdown, I want bright, long-lasting blooms, but also low maintenance: pot-tolerant species able to cope with my reduced visits to the garden.
With a little substitution here and there, hard-wearing, colourful plants can be potted to rousing effect, whether you have a garden, a balcony or a single front step. Here’s how to do it.
Prepare your pots
Tin cans, colanders or packing crates can all be repurposed into plant containers. But small-scale terracotta is surprisingly inexpensive, especially secondhand, and you want your pots to last. I’m fairly addicted to the Pot Company’s Long Tom Terracini range: simple, attractive and sturdy.
Next, the potting mix. While the plants mentioned here prefer free-draining soil, in the pot you’ll want a water-retentive medium. A base layer of broken crockery or horticultural grit will take care of drainage; then add a handful of woodchip, homemade compost, coir fibre or garden soil to ordinary potting compost. These improve water-holding capacity and offer alternatives to vermiculite, perlite or peat. After planting, a top mulch of grit will further reduce water loss.
Pots for a sunny spot
The daisy tribe is a good place to start for dependable summer colour. Of the marguerites, Argyranthemum frutescens is most popular, but try the all-yellow A. ‘Jamaica Primrose’ for its looser frame and generous blooms. Smaller is the Mexican fleabane, Erigeron karvinskianus, while the North African daisy, Rhodanthemum ‘Marrakech’, offers a pink to rival the brightest seaside thrift.
Succulents are practically built for sunny containers, supplementing shallow roots with water-storing foliage. Hylotelephiums (try ‘Herbstfreude’ or ‘Brilliant’) flower beautifully, as do saxifrages, with their elegant sprays of pink-white petals. Consider the lighter ‘Headbourne’ agapanthus hybrids in place of typical moody blues; and for pelargoniums try the cheery ‘Lemon Kiss’ or elegant P. sidoides. Forgo petunias for the similarly trumpeted Mirabilis jalapa.
Flowering herbs
Herbs make great pot plants and there are bright-flowering alternatives to all the usual suspects: the lemon-yellow pompoms of Santolina rosmarinifolia, aromatic ‘Silver Queen’ thyme or the white-flowered Teucrium chamaedrys ‘Album’. For lavender there’s L. angustifolia ‘Rosea’ (a soft pink mirrored in Verbena rigida ‘Polaris’) and feverfew (Tanacetum parthenium) makes a lovely scented addition. Chives (Allium schoenoprasum) are cheerful, and last year, I fell in love with anise hyssop (Agastache foeniculum); bees and butterflies adored it, too.
Long-lasting fillers
Within the same plant family as agastache are calaminthas and salvias, both offering a long flowering period and compact foliage. Frothy calamintha cultivars such as ‘White Cloud’ or ‘Montrose White’ could be repeated to tie pots together, as could the striking variants of microphylla and greggii salvia species. ‘Trelissick’, ‘Stormy Pink’ and ‘Royal Bumble’ extend slender stems of vibrant, bell-shaped flowers that will continue well into autumn. The white, tender perennial Euphorbia hypericifolia ‘Diamond Frost’ also creates a mound of prolific, airy flowers.
Pots for semi-shade
Shadier pots are more tricky, but strong yellows can be found in Oxalis spiralis ‘Zinfandel’ and the tall spires of Ligularia przewalskii. On the blue-pink spectrum there is Geranium pyrenaicum ‘Bill Wallis’, Lobelia erinus ‘Cambridge Blue’, Aconitum napellus (all parts are poisonous) and my new favourite, Tinantia pringlei – a Mexican native with spotted foliage and lavender flowers. For whites, try Eurybia divaricata (wood aster), rugged Liriope ‘Monroe White’ and aromatic Houttuynia cordata, whose flowers practically glow in the dark.
The all-rounder
If you grow just one potted flower, choose Campanula poscharskyana. This purple bellflower favours sun or partial shade, creeps mischievously from its pot and will flower right up until the trees drop their leaves.
