Growing Palms from Seed

by Ian Edwards

Linospadix monostachya sets seed readily and self-sown seedlings occasionally appear, but they are slow growing. Some other palms regularly produce self-sown seedlings: Howea forsteriana, Sabal minor, Trithrinax brasiliensis and Arenga engleri. The latter become scattered about the garden, no doubt by birds. They are easily identified by the characteristic shape of the first leaflet which is silvery underneath. Potting up such seedlings gives you a start of a year or two.

Unwanted seedlings also appear around the garden,especially Phoenix sp., easy to identify by the groved date-like seed and Bangalows, also easy to recognise by fine hairs on the stem. These weeds are easily pulled out.

If you are a palm grower and are lucky you can collect seedlings in your own garden. Many chamaedoreas will self-sow in Sydney. Chamaedorea cataracterum, C. elegans, C. glaucifolia, C. microspadix, C. radicalis, C. schiedeana and C. tepejilote have all produced seedlings under or near the mother plant.  Thus your own garden may be a source of seeds. Some palms like Areca triandra set seeds dependably. Others are more erratic.

Seeds

Seeds are more likely to set after good rainfall; if the inflorescences appear in spring, and if there is more than one inflorescence or another palm is flowering. Apart from the self-sowing types mentioned above, I have occasionally been able to germinate seeds from Arenga cordata, Calamus caryotoides, Chambeyronia macrocarpa, Euterpe edulis, Lytocaryum weddeliana, Synechanthus fibrosus, and after hand pollination, Chamaerops humilis.

Again, the easiest and most rewarding are the chamaedoreas. Most species set fruit if you have both sexes, even better with hand pollination – and they germinate readily.

Fruit ripening on Chambeyronia macrocarpa

 If you want rare seeds, there are suppliers who advertise on the internet, but they can be quite expensive and germination is by no means guaranteed. If you travel abroad and are lucky enough to find some ripe palm seeds, be sure to clean off all the fruit and put the seeds into a clear plastic bag with a label showing the botanic name. Declare them at Customs. Most palms seeds are allowed in, although there are rumours that this situation may not last.

Seeds from your own garden or that of a friend should germinate well, being fresh. Another advantage of such seeds is that you are germinating a palm that you know will grow well in our climate. During the years when the International Palm Society had a seed bank I germinated many species, only to have most die when young. They were not suited to our climate.

 In spite of that high mortality rate there are a some survivors in the garden that I would not have been able to obtain any other way. They include Archontophoenix maxima, Brahea armata, Brahea brandeegei and Brahea edulis,  the ‘Hookeri’ and ‘Houilou’ forms of Chambeyronia macrocarpa, Cyphophoenix elegans, Dypsis plumosa, Rhapidophyllum hystrix, Rhopalostylis baueri, Synechanthus fibrosus, Syagrus schizophylla, Trachycarpus martianus and Trithrinax schizophylla. However nearly all the chamaedoreas  survived, the exceptions being a few species from mountain cloud forests, such as Chamaedorea undulatifolia..

Germination                                                 

Many ways have been suggested for germinating palm seeds, most of which I have tried over the years. Now I use a simple and reliable method, suited to an amateur wanting to germinate a few seeds without going to any trouble. First of all the seeds must be cleaned of fruit pulp.  Ripe chamaedorea fruit are easily cleaned by simply squeezing them, making the seed pop out. For most other seeds the fruit will need to be scraped off with a sharp knife.  Some palm fruits irritate the skin, so it might be best to wear gloves. Then wash the seeds well: some palm fruits are said to contain chemicals that inhibit germination. If you have had dry seeds sent to you, soaking them in water for two days is usually recommended. I still do this, although recently the need to do so has been questioned. Another step, again queried by some, is to disinfect the seeds. It is easy enough to do: 10 minutes in 10% bleach.

Germinate the seeds in cocopeat, as the coconut coir wets and rewets much more readily than real peatmoss. It should be damp but not wet. About 2–3 cm in the bottom of a sealable plastic lunch bag, size 15 x 9 cm, is suitable for a dozen or so of most seeds, although for large seeds you will need fewer seeds and more cocopeat, enough to cover the seeds.

 Finally, hang up the bag by means of a noose of string, in a place that is warm, but not where any sunshine can get onto the bag and overcook it.

 Nothing will happen for at least two months, or more than four months if the seeds are bagged up before or during  winter. It is a good idea to have an occasional look– there should be a few drops of moisture on the inside of the bag if the cocopeat is at the right dampness.

 It is best to leave the seedlings as long as possible in their bag, which is when they are “fighting their way out of the bag.” At this stage of their lives they need only to be moist, obtaining all their nourishment from the seed. When the seeds germinate their roots usually become tangled along the bottom of the bag, but they are tough and not easily broken, and it is not too difficult to disentangle them when the seedlings are removed. 

 When the time comes to pot up the seedlings they can go directly into a potting mix. I use the best quality mix that I can find. It is expensive, but the pots are small. For a few years I used Debco Professional, but it went off the market and I now use Debco Terracotta and Tub. This has water crystals that are probably not needed, but, importantly, it has a wetting agent, Saturaid, which ensures perfect drainage. Yates Professional has also been satisfactory, but is rarely available in our area. Nowadays I rarely lose a seedling, but in earlier years lost many from centre rot, which in retrospect I think was caused by less than perfect drainage. Excessive dampness sets up the seedlings for fungal infection, and by the time the disease is noticed it is too late for fungicides to be of any use. I repot the seedlings as they grow, about once a year.

 In the shadehouse the only major hazard is a spider mite attack, which can be quite sudden, causing leaves to lose their green and if untreated, death of the seedling. The mites appear to like some chamaedorea seedlings, so I watch these carefully, magnifying glass in hand.

 Nowadays there is available a much greater range of palms, so who would want to grow them from seed?  The answer is that there is much satisfaction to be gained by germinating your own palms and watching them grow, rather than relying entirely on ‘bought ones’. It is fascinating to see how much variation there is in the time taken for seedlings to mature enough to be planted out. Compare the size of the seedlings below. There is a 50 cent coin at back of each pot for scale.