Monday, February 20, 2012

Leucadendron argenteum (Silver tree)

Leucadendron argenteum is one of our best loved and most beautiful indigenous trees. The long silky hairs on the leaves give the tree it’s attractive, characteristic shimmering silver sheen. This striking silver sheen is more pronounced in the dry summer months when the hairs lie flat on the surface of the leaves to prevent drying out. In the wet Cape winter the leaves lose their shine as the hairs stand upright to facilitate water loss and air circulation, giving the tree a dull green appearance. The handsome Silver tree is so popular that the Cape Peninsula Parks and Forestry department plant around 1000 of these magnificent trees annually. To survive the fires that are a common feature of fynbos, Leacadendron argenteum has evolved a reseeding strategy. The seeds of adult trees that are killed in a fire are kept safe in the sturdy cones that remain on the tree, and are released en masse after the fire. The Silver tree is dioecious meaning that the male and female trees are separate.
Botanical Name
Leucadendron argenteum
Common Name
Silver tree
RSA National Tree No’
The lovely Leucadendron argenteum is a versatile and showy addition to any landscape. When planted as a single specimen, these trees add interesting colour and texture to even the smallest garden, and for larger gardens, a group of three or five of these magnificent trees create a stunning effect.  The Silver tree requires good drainage, and , plenty of acid compost made from pine needles and oak leaves should be added to the planting hole. As these beautiful trees have a dense but slender upright growth habit they are extremely useful for planting along a boundary fence for privacy, as well as creating an effective yet highly attractive wind break. Leacadendron argenteum is widely used in parks and built up urban areas where the beautiful silver foliage is a perfect foil for other plants. Squirrels and other small mammals relish the seeds in the cones while a number of bird species are attracted by the small beetles that are found on this popular tree.
8 – 10 m
2 - 3 m
Growth Habit
The Silver tree is a forest margin species and occurs naturally on the cool eastern and southern mountain slopes below 500m
The smooth bark is thick, up to 20mm, and whitish to pale grey with horizontal leaf scars
The 15 x 2 cm lanceolate leaves are densely covered with fine, light reflecting, silky silver hairs and distinct veins
The solitary, roundish, cone-like terminal inflorescences are surrounded by involucral bracts. The male is yellowish silver while the female is silvery and often tinged with pink.
The fruit consists of a nutlet with a feathery perianth attached which acts as a parachute carrying the fruit on the wind
The large, dark roundish seeds are 10x8.5x5.5mm in size and are contained within the female cones.
Growing regions
Although it has been suggested that the lovely Leucadendron argenteum is endemic to the eastern slopes of Table Mountain on the Cape Peninsula, there are also notable populations on Paarl mountain, Simonsberg and the Helderberg
Growing conditions
Silver trees prefer a sunny to semi shaded aspect with well drained, acid soil and some protection from frost. Winter watering is required when planted outside the winter rain fall area
Best season
All year
Leacadendron argenteum will tolerate windy and dry conditions as well as some frost. Protection from heavier frost is advised
The Silver tree is propagated from seed which has been planted in a good seedling mixture and kept moist until the seedlings appear or, if quicker results are preferred, from cuttings, grafting or budding
Growth rate
The celebrated Silver tree was first recorded in the early 17th century when it was widespread on the mountains of the Peninsula area. The tree was so popular that it inspired landowners to give their properties names such as Witteboom, Silverhurst and Silverboom. The leaves of the Silver tree were pressed and dried and used by artists to paint local scenes which were sold as souvenirs to tourists. In 1753 the Proteaceae family was originally named after the Silver tree by Linnaeus as Protea argentea and only in 1771 did he redefine the Protea resulting in our understanding of this popular genus today.
      L. argenteum Flowers & Leaves   L. argenteum Seed           L. argenteum Bark

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