How to Grow a Norfolk Island Pine? A Detailed Guide to the Latest Cultivation Methods

The Norfolk Island pine is also known as the Australian pine, scale-leaved Norfolk Island pine, tower-shaped Norfolk Island pine, etc. It is a tree of the genus Araucaria in the family Araucariaceae, and together with the cedar, Japanese umbrella pine, coast redwood, and golden larch it is known as one of the world's 5 great park tree species. It originated in the southeastern coastal regions of Oceania, and is now cultivated outdoors in courtyards in Guangdong, Fujian, Taiwan, China, Hainan, Yunnan, Guangxi and other places in China. Let's take a look below at how to grow a Norfolk Island pine!

Growth Habits of the Norfolk Island Pine

The Norfolk Island pine likes light, while seedlings prefer shade. It likes a warm, humid climate and is not tolerant of drought or cold. It likes fertile soil. It grows relatively fast, has strong sprouting ability, and is highly wind-resistant. In winter it needs plenty of sunlight, and in summer strong direct sunlight should be avoided. It fears the dry gales of northern springs and the blazing sun of midsummer. It grows best under environmental conditions with a temperature of 25-30°C and relative humidity above 70%. For pot cultivation, a loose, fertile potting soil with high humus content and strong drainage and aeration is required.

Propagation Methods of the Norfolk Island Pine

1. Sowing: When propagating the Norfolk Island pine by sowing, because the seed coat is hard and the germination rate is low, it is best to break the seed coat before sowing to promote germination. In addition, seedlings from sowing are easily harmed by pests and diseases, so the soil used should be strictly sterilized. It is best to germinate the seeds in a sand bed or use the above-mentioned seed-coat-breaking sowing method to increase the germination rate. Generally, germination takes about 30 days.

2. Cuttings: Propagation of the Norfolk Island pine by cuttings is relatively easy and is widely used. Cuttings are generally taken in spring and summer, but the main branch must be selected as the cutting; plants grown from side-branch cuttings are crooked and not upright. The cuttings are 10 to 15 cm long. After planting, under conditions of 18°C to 25°C and relatively high air humidity, they can take root in about 4 months. If the base of the cutting is soaked in 200 ppm indolebutyric acid for 5 hours before cutting, rooting can be promoted earlier.

Transplanting Techniques for the Norfolk Island Pine

1. Root protection: Norfolk Island pine seedlings have few lateral roots and fine fibrous roots, which can easily wither and dry up if not handled carefully, so protecting the seedling root system is very important. First, they should be transported with the pot and soil, and the original potting soil should be kept moist. Second, after the seedlings are bought back, they should be planted immediately. If planting cannot be done right away, they should be placed in a cool, humid place and must not be exposed to the sun, so as to protect the seedlings, especially the roots, and keep them fresh and alive. In addition, when winter temperatures are low, the roots are easily frozen during transport, so attention should be paid to keeping them warm.

2. Careful planting: When planting the Norfolk Island pine, the seedlings should be kept with their original soil as much as possible. The planting soil should be loose and fine, and too much force should not be used to press the soil at the root. After planting, water thoroughly to settle the roots. In addition, seed-sown Norfolk Island pine seedlings have long taproots, so it is advisable to plant them somewhat deep to prevent the root system from being exposed and the plant from lodging, which would affect survival.

3. Heat preservation: The Norfolk Island pine is not cold-tolerant. If seedlings are bought and planted in winter or early spring, in addition to protecting against freezing during transport, heat preservation measures should also be taken after planting, such as planting in a greenhouse or covering with an arched plastic film. At the same time, the Norfolk Island pine is a shade-tolerant flowering plant, and seedlings are even more afraid of exposure to the sun, so they should be shaded immediately after planting.

4. Broken and damaged parts: Norfolk Island pine seedlings have tender tissues and are prone to breaking and damage. The following methods can be used for remedy. For seedlings with broken roots, wash them with clean water and insert them into plain sand; at a suitable temperature, they can re-root from the cut surface in 1-2 weeks, and after the root system is well developed they can be planted. For seedlings with broken buds or broken stems but with leaves, they can be planted as usual, and after surviving they will sprout new buds after a certain period of time.

Cultivation Methods for the Norfolk Island Pine

1. Soil: The Norfolk Island pine is cultivated in Guangdong, Fujian, Hainan, Yunnan, and Guangxi in China, while in the major cities of the Yangtze River basin and to the north it is grown in pots and overwintered in greenhouses. The most suitable potting soil for cultivation is prepared with leaf mold, garden soil, and river sand at 1/3 each, plus a small amount of base fertilizer.

2. Watering: The Norfolk Island pine likes a humid environment, so during dry seasons and summer, clean water should be sprayed on the leaves frequently. This not only increases air humidity but also keeps the leaf color fresh and bright, which is very beneficial to its photosynthesis. During the maintenance period, watering should be appropriate. In summer, watering should be sufficient to promptly replenish the needs of leaf transpiration and avoid drought damage. However, watering should not be excessive, causing water to accumulate in the pot. Usually, it is best to keep the potting soil constantly moist.

3. Light: The Norfolk Island pine likes sufficient sunlight. In northern regions, it is generally moved in early May to a south-facing balcony or a sunny spot in the courtyard, and after summer begins, appropriate shading should be provided to avoid exposure to the sun. In northern regions, cultivation should be moved indoors by late September to early October, placed in a sunny spot, and watering should be controlled

4. Temperature: The Norfolk Island pine likes a warm, humid climate and is not tolerant of drought or cold. It can grow under a variety of different temperatures, but its cold tolerance is not strong. The optimum growth temperature is 7-24°C. If the temperature rises, the air humidity around the plant should be increased.

5. Fertilizing: The Norfolk Island pine grows relatively quickly, so during its vigorous growth season it needs frequent topdressing to supplement the nutrients needed for growth. Generally, starting from when new buds sprout in spring, apply 1-2 times per month of decomposed dilute cake fertilizer water for it to absorb and use, so that it can grow strong and healthy.

6. Pruning: The Norfolk Island pine easily develops a phenomenon in which the lower branches and leaves gradually turn yellow and fall off, causing the whole plant to be top-heavy and affecting its appearance. Careful management and necessary pruning are required during maintenance.

7. Pests and diseases: The diseases of the Norfolk Island pine include leaf spot, branch blight, and root nodule disease. For leaf spot and branch blight, spraying with 70% thiophanate-methyl 800 times solution or 65% zineb wettable powder 500-600 times solution can be used for control. For canker disease, apply 40% asomate 100 times solution or potassium permanganate 1000 times solution to disinfect. For root nodule disease, soak with streptomycin 1000 times solution. The main pest is scale insects. When only a small amount occurs, wash the leaves with clean water; when more serious, spray with 40% omethoate emulsifiable concentrate 500-1000 times solution to kill them.