Araucaria excelsa (Christmas tree)
Araucaria excelsa (Araucariaceae) is a beautiful, evergreen, conifer tree of pyramidal shape which reaches up to 65-70 m tall in its original habitat. It is native to Norfolk Island (a sub-tropical Island in Pacific Ocean). Araucaria excelsa is also known as Christmas tree, Norfolk Island Pine, Andes pine and Australian Pine etc. It is the synonym of Araucaria heterophylla. The tree has straight vertical trunk that is 1.25-1.75 m in diameter. The branches are heavy, horizontal and spreading throughout without any support. The leaves or needles are crowded together on branches in spiral shape. The mature needles are ovate and scale-like. The male cone is 5 cm long, oblong in shape while female cone is erect, sub-globose in shape, 10-12 cm long and 12-15 cm in diameter. The seeds are oblong in shape, winged and up to 3 cm long & 1.2 cm wide.
Landscaping ideas of Araucaria excelsa
Araucaria excelsa can be grow as ornamental plant that reaches up to 1-2 meters in height when keep in indoor. It grows slowly in indoors approximately less than 15 cm a year. This property makes it an attractive plant at homes, living rooms and entrance halls in containers. Araucaria excelsa is the only specie of Araucaria which can be use as indoor Christmas tree. It can also be plant outdoors separately in gardens, streets and avenues. The tolerant nature of plant from salt and wind makes it an ideal plant for coastal areas in tropical and sub-tropical regions.
How to propagate Araucaria excelsa
Araucaria excelsa can be propagate through seeds or cuttings. The cuttings taken from dynamic material will grow upright. But the cuttings take from horizontal branches will maintain horizontal growth instead of normal upright growth. The rooting take place within 2 to 3 months. The plant should be planted in large enough container for it rooting. However, it will take several years to reach the size of purchase plant.
How to take care of Araucaria excelsa
- Light Exposure: Araucaria excelsa grows well in medium light.
- Soil: It prefers well drained soil however, it can grow on acidic and salty soil.
- Temperature: The ideal temperature for plant growth is 7-24˚C.
- Humidity: It prefers relative medium humidity therefore, occasionally mist spraying is require.
- Dryness: The plant will show loss of needles if the atmosphere is too dry or exposed to sun.
- Space for roots: If the plant is keep in indoor in a container, then it require enough space to spread its roots.
- Watering: Do not allow the water to stand in pots because it do not need much water.
- Pruning: It do not needs pruning at all but dead branches should be remove.
- Frost Tolerance: It is tolerant to the frost but extremely low temperature cause damage to pot plants.
- Fertilization: It requires liquid fertilizer after every two weeks for rapid growth.
- Diseases: The most common disease of this plant is “Stem rot” which turns the stem into brown coloration that leads to the death of plant.
- Pest Attack: Mealybugs are the most common pests of Araucaria. They causes white areas on leaves and stems but can be remove by spraying with appropriate pesticide.
Uses of Araucaria excelsa
- The wood of Araucaria excelsa is soft, high quality and good for turning. At one time it is use heavily for construction purposes.
- It is grow as an ornamental houseplant in areas where winters are too cold and used as a Christmas tree.
- The stem releases resin and gum which showed antiulcerogenic and antibacterial properties.
- Its leaves used as an effective, cheap and environmental friendly biosorbent that removes chromium (Cr) and lead (Pb) from nature.
- Araucaria excelsa is one of the 50 plants list by NASA that have air purifying property and reported to absorbed formaldehyde.
- It has gain the Royal Horticulture Society Award of Garden Merit.