Practical Seedling Growing

Growing Araucaria from Seeds

    Araucaria are dioecious tree species. So it is necessary that male and female trees will be close to each other to ensure a good fertilisation of the seeds. Empty seeds are easy to detect pressing gently the seed between the fingers. If the seedcoat does resist, there is a fair chance that the seed will be viable. As Araucaria are difficult to climb, usually the seeds can be collected after they have fallen on the ground in September-October (in the Northern Hemisphere). As the seeds are edible, it is better not to wait until squirrels will go for them. Araucaria seeds are difficult to store. It is recommanded to store them moist and even better to sow them immediately. Araucaria seeds can be sowed anytime indoors. The first step is to soak the seeds in tap water. If very fresh, they will fall immediately to the bottom (to let them stay for 24h). Otherwise to wait until they will fall, usually less than 72h.

Sowed Seeds
    When the seeds are ready, they need simply to be picked point ('sharp' end of the seed where the root will appear first) down in one medium that will not dry too quickly (better not to use peat). The deeper the pot the better. The top of the seed will remain above the soil surface (something like 3/4 or 4/5 of the length of the seed is burried - see the pictures). The medium must be kept moist without excess. If there is enough place, it is even better to sow the seeds in individual tubes, sparing later repotting, and avoiding to disturb the roots. It is possible to keep the pot at room temperature. To hasten the germination, the pot can be put on a radiator (bewaring though of excessive heat, and watering before the medium will dry). It is also possible to keep the pot in a cool place until the next Spring. Care must be taken even at low temperature so that the medium will never dry completely. It seems that germination does not occur at low temperatures. Sunlight is not needed for germination.
Sowed Seeds

    Germination can occur as quickly as 2-3 weeks after sowing, but it is not possible to see anything (except removing the seed from the medium) until much later. Last germinations could still occur some months later. The deep pot will allow the root to grow straight for the first months. Possible and even recommanded is to repot the seedlings into individual tubes as soon as possible when it is known about germination. Only when the true leaves will start growing (the germination is hypogeal), will the germination become apparent. The seedcoat is pushed out of the medium. If the leader remains stuck inside the seedcoat, it is recommanded to gently remove the seedcoat. This 'operation' will even be mandatory with seeds of Araucaria bidwillii.
Araucaria araucana Germinating Seed
Araucaria araucana Germinating Seed

Araucaria angustifolia Seedlings
    Once the germination began, patience only is needed. Araucaria araucana is a slow grower during the first years. The other subtropical species are growing more quickly if only heat and light are provided. The main mistake to be avoided is to give too much water. Araucaria araucana accepts to grow in the shade when small. Limestone soils should be avoided.
Picture below :
Araucaria angustifolia seedlings before repotting. Notice the taproots. The smaller lateral roots are spreading at an angle of 90°.
Araucaria angustifolia Seedlings

Araucaria araucana, angustifolia and bidwillii are grown from seeds in the nursery of the Arboretum. The last two will be test1ed for hardiness.

Text & Photos : © Arboretum de Villardebelle