Acacia dealbata Gaulois Astier

Grafted Acacia dealbata Gaulois Astier has all the qualities of the Mimosa or Blue wattle, but does not have the suckering characteristic that is rightly criticised when it grows on its own roots. It also has the advantage of tolerating limestone soils very well. Its only weakness is the low hardiness of its rootstock, which perishes below -5 to -6°C (23 to 21.2 °F) if not protected. It is a large and beautiful evergreen bush that flowers early in late winter or spring in mild climates, in an abundant and fragrant yellow pompon-infused cushion. This mimosa is a fantastic hedge shrub or a very beautiful specimen to plant in isolation in favourable climates. It will also make a superb specimen, planted in a large pot, to be stored away in winter in cold regions. Its flowering branches are sublime in winter bouquets.

Acacia dealbata, native to Australia, should not be confused with the tree we call acacia, which belongs to the Robinia genus. The latter is a true small tree, suckering when it grows on its own roots, fast-growing but with a short lifespan. It was imported to Europe as early as 1771 and arrived in France in 1804. This plant, belonging to the Fabaceae family and the Mimosaceae subfamily, was widely planted in the 19th century on the French Riviera, which offers a mild, warm, dry climate in summer, and a slightly acidic soil – very favourable conditions for its establishment – to such an extent that this species has become invasive there and poses a threat to the survival of the local flora. 

It is available as a plant grafted onto A. retinodes, the non-suckering perennial mimosa that tolerates limestone soils much better. This small tree with a single trunk has a rounded and dense habit, reaching 5 m (16 ft 5 in) in height and 4.5 m (14 ft 10 in) in width at maturity in favourable conditions. Its dimensions can easily be contained through post-flowering pruning or cultivation in pots. The bark is smooth and greyish in colour. It flowers abundantly in a truly spectacular fashion from January to March, depending on climatic conditions. Its small round flowers consist of bright yellow stamens in clusters and are gathered in axillary racemes. Their scent is highly distinctive: a very fresh herbaceous start gives way to a divine scent of honey and a powdery fragrance. Its velvety branches bear strongly divided leaves, green with bluish and silvery reflections. Each leaf is divided into leaflets, themselves divided into tiny leaflets. It is hardy down to a minimum of -6 °C (21.2 °F), but it has excellent resistance to summer drought.

Blue wattle Gaulois Astier, when planted in the ground in mild climates, can be placed as a standalone specimen, in a hedge or in a row, as a natural privacy screen, due to its shading power. It can be combined with other tender shrubs with an exotic appearance, such as evergreen ceanothus, Caesalpinia gilliesii, Jacaranda mimosifolia (Blue Flamboyant), Sesbania punicea, escallonias, callistemons, Grevillea robusta, or Coleonema album.

For your bouquets: pick the branches when the flowers have just opened. Place them in slightly sweetened warm water and regularly add water to the vase. Keep your bouquet in a moderately heated room and take it out at night if there is no frost.