Rhus glabra Laciniata - Fern-leaved Sumach

Rhus glabra 'Laciniata', also known as Cutleaf Smooth Sumac, Smooth Sumac or Vine-Plant, is a bush with long green-blue pinnate leaves divided into dentate leaflets. In autumn, it becomes unique and almost theatrical for two reasons: first, because of the richness of the colours of its foliage, and second, because of its velvety amaranth conical clusters of fruits that persist throughout the winter.

The Smooth Sumac belongs to the family Anacardiaceae and is native to the eastern and western United States (Arizona, Florida to Maine). The growth of this bush is fast and its adult size will not exceed 2.50 to 3 metres in all directions.

The Cutleaf Smooth Sumac has a bushy habit. Its foliage is exceptionally decorative: its pinnate leaves, green-blue and glaucous on the underside, reach 35 to 50cm (13.8 to 19.7in) in length and are divided into lanceolate, dentate, and glossy leaflets. They truly ignite in autumn when gold, orange, crimson, and raspberry red succeed each other and blend in a flamboyant range of colours. The summer flowering (July-August) in the form of greenish conical panicles, 16 to 25cm (6.3 to 9.8in) long, is followed on female trees by intense red drupes, velvety and clustered, 15cm (5.9in) long. The stems are smooth, inermous, red and covered with bloom.

Plant the Rhus glabra 'Laciniata' in any type of soil, even limestone and poor, dry or moist but well-drained soil. It will thrive in partial shade or full sun, but it is commonly accepted that the autumn colours will be more intense with a sunny exposure, the bush should receive at least six hours of direct sunlight per day. A sheltered position from the wind is preferable to preserve the foliage. If not pruned severely enough, this sumac quickly becomes bare at the base and naturally takes on the appearance of a small tree. To maintain a beautiful habit, it may be necessary to remove dead wood or tangled branches. On the other hand, if you want to keep it as a bush, it should be pruned to 50cm (19.7in) from the ground. Pruning should be done before the start of the vegetation (from February to April). Rhus glabra develops trailing roots and naturally suckers. Care should be taken not to damage its roots to avoid accentuating this tendency. It is necessary to monitor the possible appearance of suckers, which can be easily removed.

The Cutleaf Smooth Sumac provides light shade and can shelter a perennial flowerbed with peonies, Brunneras, and can be associated with Scillas, snowdrops, and daffodils for spring, or cyclamens for autumn. It can also be planted as a standalone specimen, creating a changing spectacle by itself. For vibrant backgrounds, it can be associated in a hedge with European spindle tree, Persian Parrotia, smoke trees, or castor oil plants. It is worth noting that its resistance to drought once established, its tolerance to pollution and sea spray, and the hardiness of Rhus glabra 'Laciniata' allow it to be grown in many situations.

Rhus glabra 'Laciniata' carries a toxic milky sap in its branches. It is used in homeopathy but can cause asthma and allergies. The fruits can be macerated in water to obtain a refreshing and acidic beverage (hence its name of vinegar tree).