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First pick for any chocolate garden has to be the chocolate cosmos, Cosmos atrosanguineus, for its deep red, velvety flowers and dark chocolate scent. A new variety, ‘Chocamocha’ is smaller (45cm), sturdier and more strongly chocolate-scented than the species. It gives a long show, from June to September, in a hot, sunny spot with good drainage. It is half-hardy, so either lift it and store it over winter, or protect the roots with a cloche or a thick layer of dry mulch. Buy three ‘Chocamocha’ plants for £12.99 or six for £16.99, saving £8.99. All orders include free p&p. To order call 0330 333 6856 quoting ref GUA637. Or shop online at guardian.co.uk/offers/plants. Supplied as jumbo plug plants. Delivery from next month.

By contrast, the spring-flowering chocolate vine, Akebia quinata, requires no attention. It will grow in any soil, in sun or shade, but to appreciate its chocolate-vanilla scent to the full, drape it over an arch or trellis, where the clusters of delicate, burgundy flowers can dangle at nose height. In my garden, it romps through a hedgerow, where it easily withstands attack by clipper and flail: it can make 10m high x 2m wide in a more orderly setting.

Equally easy and vigorous is Clematis montana var. wilsonii (3-5m), a white-flowered montana clematis with a powerful chocolate scent. The nodding, pink-flushed buds are a delight, opening later than other montanas to crinkly flowers with tousled green bosses. Feed it well, and it will grow in cheerless spots in many town gardens, tolerating shade and lighting up a dull space from May to July.

Jenny Gaunt of Dark Star Plants in Yorkshire specialises in plants with dark leaves and flowers. Selecting only three foliage plants from her extensive list causes her anguish, but she settles on ones that will thrive in almost every situation. For a shrub, she looks no further than the chocolate tree, Physocarpus opulifolius ‘Diabolo’. It is hard to think of anything less devilish than this obliging creature, which seems to thrive in the poorest soil, in sun or shade, swiftly making a shapely fountain of foliage (3m x 5m) that provides an elegant backdrop for showier silvers, golds or lime greens. Red flowers look knockout against it, too.

For the front of the border, Dark Star Plants recommends knee-high ‘Chocolate Ruffles’ – one of the earliest and best of the evergreen, dark-leaved heucheras. The ruffled, cocoa-brown leaves have deep pink undersides. Finally, the glorious Angelica ‘Ebony’ – a spectacular umbellifer (90cm) with deep-cut leaves the intense near-black of best bitter chocolate. Although biennial, this angelica seeds freely.

Chocolate’ is a popular moniker for flowers, but rarely accurate – the delphinium ‘Kissed By Chocolate’ is a mottled white, the dahlias ‘Karma Choc’ (above) and ‘Chocolate Sundae’ both brooding crimson.

The bearded iris ‘Dutch Chocolate’ is perhaps more chestnut than chocolate. But who cares? It has the silky sumptuousness of a luxurious Leonidas truffle, with huge, fragrant blooms that can last up to four weeks, and will often return in autumn after a hot, dry summer. It needs a well-drained spot in full sun, and should be planted with the top of the rhizome exposed. The delicate chocolate columbines are different in their appeal. Aquilegia viridiflora ‘Chocolate Soldier’ (30cm) has dark bells in neat, green jackets – a diva for the alpine trough or rock garden. ‘Fruit And Nut Chocolate’ (35cm) is tougher, and its spicily-scented flowers arriver earlier and last into May.

Equally dainty is Digitalis parviflora ‘Milk Chocolate’ (above), a perennial foxglove (60cm) with spires of tiny trumpets in the smudgy brown of milk chocolate fudge. It does well in both sun and shade, and looks wonderful planted in large drifts. The flower spikes last well into the autumn – a boon to wildlife as well as chocaholics.