Cuphea hyssopifolia Purple

Cuphea hyssopifolia 'Purple' is an undershrub of Mexican origin, very popular in gardens with warm climates. It forms a highly branched bushy clump, as wide as it is tall, remaining compact without requiring pruning. Its dark green evergreen foliage is adorned with small single purple-violet flowers which renew from May to autumn. Only gardens located in the mildest areas will be able to grow it in the ground. In cooler regions, it can be planted in a pot to be brought indoors to protect it from frost. Withstanding heat well, it is easy to grow in full sun provided it is regularly watered.

The genus Cuphea, which includes more than 250 species, is a member of the Lythraceae family, which includes genera of herbaceous plants in many climates (including Purple Loosestrife in Europe), and also woody plants in warm climates, like pomegranate. Cuphea hyssopifolia is an undershrub native to Mexico and Honduras, hence its common names of Mexican heather or Mexican star. It is a short-lived plant, but easily self-seeds in warm climates, and can even become invasive. It also has the particularity of easily layering when branches touch the ground.

'Purple' is a horticultural variety very similar to the species, with purple-violet flowers. This undershrub forms a dense and highly branched clump, 50cm (20in) tall and as wide, or a little more, as it tends to widen over time. It bears small evergreen leaves, which are elliptical, elongated, and narrow, measuring 2 to 3cm (1in) long. The leaves are a fairly dark green colour. It has thin, erect and slightly arched branches, with lateral shoots often oriented in the same plane. The branches orient themselves in all directions, resulting in a balanced habit that does not require any pruning. From May, small single star-shaped flowers appear, about 1cm (0.4in) in diameter or more, and are well distributed in the foliage. This lovely flowering, which pleasantly contrasts with the dark and glossy mass of the foliage, extends until October. Cupheas are champions of long-lasting flowering, and this species honours that reputation. Slightly hardier than Cuphea ignea, this species can only develop in the ground in warm areas with mild winters. Resistant to light frosts of around -3 to -5°C (26.6 to 23°F). Occasionally, the foliage can be burnt during colder than normal winters. In this case, a light pruning in spring generally allows the plant to produce new shoots. It requires the best conditions to withstand winter: a sunny exposure, well-drained, non-calcareous soil, and a sheltered position against the mistral wind. Regular watering is required during the flowering period (it is a tropical plant, after all), as well as regular low-dose potassium-rich fertiliser applications (mixed with the watering water).

In cool regions, it should be planted in a pot to be sheltered in winter in a frost-free, bright room.

WIth its small dimensions, Cuphea hyssopifolia 'Purple' is an excellent border plant for gardens that can accommodate it. Plant it at the base of a clump of Strelitzia reginae, the bird of paradise, to create a strong contrast between its large leaves and flowers, and the miniature ones of the Cuphea. You can also play with shapes by planting a white-flowered Agapanthus, like Thumbelina, next to it, whose design is quite different from that of our little Cuphea. And if your climate is too cold to plant it in the garden, opt for a beautiful decorative pot. To create an exotic and blooming scene all summer long, accompany your Cuphea with Cassia floribunda, whose magnificent yellow flowers will bloom during the same period.