Pernettya mucronata

Pernettya mucronata, or Gaultheria mucronata (the two genera were merged into one, Gaultheria, in 1990), is a small heathland shrub, remarkable for its decorative fruits in autumn and winter. It displays numerous red berries from September, which contrast well with the dark green evergreen foliage. Resistant to frost, they can remain on the plant practically until the next flowering. From May onwards, small white bell-shaped flowers typical of the Ericaceae family, to which Gaultheria belongs, appear. Tolerating morning sun, this shrub thrives in partial shade, in cool and acidic soils. It takes several years to establish itself well and then suckers to form wide cushions 1.20 m (3 ft 11 in) wide and 1 m tall, without becoming invasive.

Pernettya belongs to the Ericaceae, a large plant family comprising about a hundred genera, the most well-known being Rhododendrons, blueberries, heathers (genera Erica, Calluna, Daboecia)... In general, they are known as "heathland plants", i.e. plants that grow in soils composed of organic matter with an acidic pH, with a few exceptions (Mediterranean heather Erica multiflora also grows in slightly alkaline soils...). They can also be recognised by their flowers, usually bell-shaped due to the fusion of the petals (they are called "gamopetalous").
Gaultheria therefore flowers around May, displaying pretty little white bell-shaped flowers characteristic of its botanical family. This rather discreet flowering is nonetheless visible against the shrub's dark green foliage, and its small bell-shaped flowers, about 1 cm (0.4 in) in size, are reminiscent of lilies of the valley. They give rise from September to small berries, 1 cm (0.4 in) or more in diameter, shaped like slightly flattened spheres. Their red colour is particularly decorative, and as they can withstand temperatures as low as -8 to -10 °C (17.6 to 14 °F), they can persist on the plant until the following spring, depending on the year.
Note that this species is dioecious, meaning that individual plants are either male or female, so they should be planted together to ensure good fruiting (1 male plant for every 4 to 5 female plants). Also, be cautious in the garden, as these lovely little fruits are toxic.
In terms of cultivation requirements, Pernettya fits perfectly into the typical general framework of Ericaceae, with a preference for acidic soils (no tolerance for limestone), remaining fresh, especially in summer. This shrub can be planted in the sun in cool climates, but it fears excessive sunlight combined with high temperatures, so in such climatic conditions, it is best to plant it in partial shade.

For lovers of heathland plants who do not have suitable soil, this shrub can be planted in a container, taking care to choose a suitable acidic potting mix, a location protected from direct sunlight, and regular watering. In a garden with acidic or neutral soil enriched with peat, Pernettya can be planted in a bed at the foot of taller heathland plants. Classic options include camellias or rhododendrons, but more original combinations can be created with mountain laurels (Kalmia) with their superb white, pink, or red blooms. The lesser-known but remarkable Sourwood will also be a suitable companion, with its flamboyant autumn colouration enhanced by the contrast with the dark foliage of the Gaultheria.