Many years ago I was asked by a keen gardener if I could tell her the name of the plants that she could see on apartment balconies throughout South East Asia. She said that from a distance they looked like azaleas and they flowered all year round.
I must admit I was stumped. All I could think of was Bougainvillea or perhaps Adenium. I was promptly told no, this was not what they were, and I guess my horticultural standing dropped a few notches in her eyes. It was a few years later when visiting Singapore that I put two and two together and saw Poysean Euphorbias in their full glory.
While these plants may look like azaleas from a distance, take a closer look and you will see that their affinity lies more closely with the common Crown-of-thorns (Euphorbia millii).
A plant in full flower is a sight to behold. The top and sides of the plant will be covered in ‘flowers’ of burgundy, red, pink, orange, salmon, cream, yellow or chartreuse. ‘Flowers’ can also be bicoloured – such as cream with a pink edge or salmon with a green centre. Often most of the foliage is obscured from view. Plants stay in ‘flower’ all year round and the ‘flowers’ have a long life.
Now for some botany. To be more precise the colourful ‘flower petals’ are in fact bracts –technically colourful modified leaves. But it gets even more complicated here, as the true flowers are tiny appendages and surrounded by a structure called the involucre. In euphorbias this is termed a cyathia (plural cyathium) and this is what you see nestled in among those colourful bracts.
These plants are exceptionally hardy. They tolerate extended periods of dry weather as well as heavy summer rain with high humidity. They tolerate heat and wind, including salt winds. They will perform with zero maintenance and feeding. However like any plant, a little bit of love and attention will go a long way. And they thrive in pots. No wonder they are such perfect balcony plants.
The name Poysean is used by the Thai Chinese community for the Crown-of-thorns (Euphorbia millii) and some of its early hybrids. It means Eight Saints and refers to the Eight Saints of Chinese mythology. The older Euphorbia hybrids have 8 ‘flowers’ in a bunch. To this day you will see great numbers of these plants growing in Taoist and Buddhist temple gardens.
The origin of these plants is thought to date back to the hybrids between Euphorbia millii and Euphorbia lophogona that were developed by the Somona Nursery in Germany in the early nineties. These plants proved to be popular indoor plants for the European houseplant market. This popularity has continued to increase. However these plants had limited flower colour (generally pink to deep pink) and a small flower size.
The large flowered Poysean Euphorbias we know today appeared in Thailand during the mid-nineties and the range of plants appears to have been spurred by the high prices paid for them at that time. To this day I find this transformation truly amazing. But then the Thais are master plantsmen and master plant breeders and if anyone could create the proverbial silk purse from a sow’s ear, it would be the plant breeders of this country.
Poysean Euphorbias are widely grown throughout Thailand and a visit to this beautiful country will give you many ideas on how to use them. As well as thriving in pots, they do well in raised, free-draining garden beds. The range of cultivars is truly amazing and includes plants with varied growth forms and ‘flower’ colour, sizes and shapes.
Once established, plants grow 600 to 1,500 mm (2 to 5 feet) high by 600 to 1,000 mm (2 to 3 feet) wide. Because of their mixed hybrid origin, some cultivars are slightly more upright in growth and some are more spreading. If you have a position in mind it pays to analyse the growth habit of the plant you plan to purchase. This is obvious from a young age.
Despite their popularity overseas, in Australia you are most likely to see these plants grown to their full potential in the gardens of Asian immigrants. They are widely used at entries, in courtyards and in front garden areas – generally grown in pots. No doubt this is spurred by the belief that these plants have auspicious qualities.
So why haven’t these plants taken off in Australia? I believe it is lack of familiarity and perhaps the fear of the new. To see them at their best, plants have to be large. As small plants, they can look gawky and unattractive. Plants are also slow growing. Large plants are expensive to produce and are easily damaged in transit. I am told by nurseries that tip cuttings are required to grow attractive commercial grade plants. This requires many large plants from which to harvest.
The good news is that the plants are very easy to propagate and established plants benefit from appropriate pruning. If you have a friend with a plant, you might like to suggest you would happily give it a prune to enhance its shape! Some plants throw new growth from the base and is simply a case of removing lanky branches to encourage new branches to replace them. Others send out long branching growths and these can be cut back above a selected joint.
Tip cuttings 100 to 150mm (3 to 6 inches) long root readily. However ensure the cuttings are dried for at least a week in a well ventilated, dry and shady area so that the wounds callous over. Plant cuttings in coarse washed sand or a sandy potting mix and let this mixture dry slightly between waterings.
Plants grow exceptionally well in pots. In Asia plants are often grown in large ceramic pots. They like good drainage and to dry out slightly between waterings. Use equal parts of a quality potting mix combined with sieved ash, fine gravel or coarse washed sand. Water during dry periods as plants look best if they don’t dry out excessively. However if you do go on holiday, don’t worry, Your plant may drop a few leaves or flowers but will bounce back with a bit of attention. Apply a controlled release fertiliser following the manufacturer’s recommendations. Select a fertiliser high in phosphate and lower in nitrogen such as one recommended for flowering plants or tomatoes.
In cooler climates, plants can be brought under cover or into the greenhouse in winter. Plants are frost tender, and of course, coming from tropical or subtropical areas, enjoy wet summers and autumns and slightly drier winters.
Now sit back and enjoy. It can’t get any easier than this – a spectacular flower show for most of the year and practically nothing to do!