Germinating seed of NZ’s tricky species

Posted on September 27, 2017

Spring is finally here, well officially, but given the wild weather over the last month, it makes one wonder! Still it is an exciting time at Kauri Park, with loads of plants driving out the gate and lots of new seedlings emerging in Kauri Parks’ propagation greenhouses.

This year we have employed a new seeding strategy to ensure the consistent supply of native plant species to our customers. Seeds are sown on a pumice base with a covering of seed raising mix and other ‘Colonel Sanders’ ingredients to enable them to germinate and hold as small plants for 1, 2 or even up to 3 years, depending on species.

Given the unpredictable and uneven seeding of many of our natives, this is a must in ensuring consistent supply. Some of our unique native species seed as infrequently as every 8, 9, or even 10 years, and many are biannual or triannual in their seeding patterns.

We use a number of strategies to hold our seed in good condition for several years, using various stratification methods to crack the shell of the seeds, and incorporating special ingredients within the seed raising mix to improve germination rates and inhibit damping off.

It does seem that due to New Zealand’s temperate climate, many introduced plant species grow out of control whereas our native species have several mechanisms to prevent this from happening. This makes seed fertilization irregular, and seed germination notoriously difficult. Our seed specialist, Grant Hodges, says you need to think like a plant to germinate some of these tricky species.

This year Grant has successfully germinated good volumes of many tree species including Myrsine australis (red matipo), Pittosporum crassifolium (karo), Pittosporum eugenioides (lemonwood), Pseudopanax crassifolius (lancewood), Pseudopanax arboreus (five  finger), Pittosporum tenuifolium (kohuhu), Dacrycarpus dacrydioides (kahikatea), and Hoheria angustiflia (narrow leafed lacebark), to name a few.

The seeds are germinating evenly with a high percentage germination. The evenness of the germination allows us to prick out all of the plants in one go rather than having to prick out plants from the germination trays over several weeks, due to a split germination. This in turn leads to large batches of evenly grown plants all coming ready on time for delivery to our customers.

This strategy allows us to harness nature’s productive years and spread them over the non-productive years, enabling us to meet market needs consistently every year.