About Grevillea exul subsp. rubiginosa (Brongn. & Gris) Virot
Grevillea exul grows as either a shrub or small tree. In sheltered areas, it grows as an open tree reaching up to 10 m (33 ft) tall, while in open areas it grows as a spreading shrub up to 4 m (13 ft) tall. Its leaves are 4.5–13.5 cm (1.8–5.3 in) long and 0.5–5.7 cm (0.20–2.24 in) wide, with a lanceolate to elliptic shape, conspicuous veins, and a blunt apex. The flowers are white with a greenish style end, arranged in terminal inflorescences 5–20 cm (2.0–7.9 in) long. The perianth measures 10–15 mm long and 2–3 mm wide, and is slightly dilated at its base. Before anthesis, the anthers enclose the style end, and separate after anthesis. The pistil is 26.5–42.5 mm (1.04–1.67 in) long, with a slightly oblique, elliptical conical pollen presenter. Flowering occurs from May to January, starting later in the year at higher altitudes. The fruit is a follicle that is 12–20 mm (0.47–0.79 in) long and 9–15 mm (0.35–0.59 in) wide. This taxon is widely distributed across New Caledonia, where it occurs on valleys, ridges and slopes from 6 to 1,250 metres (20–4,101 ft) above sea level. It grows in open forest or scrub, in a range of soil types including serpentine schist, skeletal soil, and alluvial sand. Grevillea exul was cultivated at the Royal Botanic Gardens in Sydney from 1850 until at least 1903, and fell out of cultivation early in the 20th century. In 1988, garden staff recollected the species to re-establish it in cultivation, and shared plant material with the Grevillea Study Group of the Australian Native Plants Society. Today, it is grown in a number of botanical gardens across Australia, including the Brisbane Botanic Gardens and the Southwest Pacific Island collection at the Royal Botanic Gardens Victoria. It is a hardy, adaptable species that can grow in a wide variety of climatic conditions, ranging from tropical climates to cold, wet winters. It can tolerate frosts down to -2 °C (36 °F) and survive dry periods with little negative impact. Plants grown on their own roots grow just as well as plants grafted onto a rootstock, most commonly Grevillea robusta. It is a long-lived plant that produces abundant flowers in its blooming season, and may be used as an ornamental shrub.
