Common Name: Dadap

General Information

Erythrina subumbrans is a deciduous tree with a spreading crown and branches armed with stout prickles; it can grow 5 - 35 metres tall. The straight bole can reach 60cm in diameter[, ].
At one time this species was one of the most widely planted shade trees for coffee and other crops in Indonesia, until large numbers of trees were destroyed by a root disease in the late 19th Century[, ]. It is still planted on a smaller scale in Indonesia for shade in cocoa, coffee and tea plantations, and on a larger scale in other tropical countries[, ]. The tree is also grown as an ornamental, valued especially for its floral display[], and as a pioneer species in reforestation projects in Thailand.

Known Hazards

All Erythrina species contain greater or lesser amounts of toxic alkaloids - these can be found in all parts of the plant but are usually most concentrated in the seeds. Concentrations vary from species to species, in some it is low enough that the plant is safely used as a food. In many, the alkaloids are utilized for their medicinal effects. We have no specific information on the concentration of the alkaloids in this species, but care should be exercised in any use of the plant that involves ingestion. These alkaloids have a curare-like action (obtained from Strychnos species) and can cause paralysis and even death by respiratory failure[, ].

Botanical References

Range

E. Asia - China, India, Sri Lanka, Myanmar, Thailand, Laos, Vietnam, Malaysia, Indonesia, Philippines.

Habitat

Moist valleys, near streams, in open locations and secondary forest at low and medium elevations[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	20.00 m
Growth Rate	Fast
Pollinators	Birds, Insects
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

A plant of low to medium elevations in the tropics, where it is usually found at elevations below 1,500 metres[]. It is found in areas where the mean annual rainfall is in the range 500 - 2,000mm and there is a maximum of 4 months with less than 100mm rainfall[]. The mean annual temperature is above 22°c[].
The trees are fairly tolerant of wind, unless branches have been damaged by borers[].
Often grown as an ornamental or to provide shade in plantations, the tree has occasionally escaped from cultivation and become naturalized. It is classified as invasive in some Pacific islands[].
Thornless forms generally produce fewer flowers and fruit than wild forms which have spines[]. The cultivated thornless forms may reach an age of 40 - 50 years, but often die earlier because of diseases and pests[].
Pruning and pollarding are very well tolerated[].
Where the tree is pruned, it is sometimes used as a medium level shade tree, interplanted with taller shade trees like Paraserianthes falcataria or Grevillea robusta[]. Elsewhere, it is not pruned and is used for high shade, interplanted with Leucaena leucocephala to provide the low shade[].
In Western Samoa, yam vines planted in a circle around a tree are allowed to cover the canopy and suppress its growth[].
The flowers contain large quantities of nectar and are a major source of food for birds during the dry season[].
All species in this genus are believed to be self-compatible. Their flowers are adapted to pollination by birds, though various insects can also cause fertilization. The various species of Erythrina can all, as far as is known, be intercrossed to produce fertile hybrids. Those species most closely related to each other cross fairly readily, but even species that are quite distant can hybridize[, ].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

Very young leaves are steamed and eaten in salads[, ].

Medicinal

A decoction of the bark is taken to the treat spleen afflictions[].

A decoction of the leaves is used as a treatment for coughs[].
The pounded young leaves are used as a poultice for women soon after giving birth and as a treatment for headache[]. The juice of the leaves is used as an eye-wash[].

Seeds contain the curare-like alkaloids erysoline, erysopine and erythratine[].

Agroforestry Uses:

Grown as a shade tree in rubber, nutmeg, cocoa, coffee and tea plantations. It is also used as a shelter crop for taro (Colocasia esculenta) and as live support for yams (Dioscorea spp.), betel nut (Piper betle), pepper (Piper nigrum) and vanilla (Vanilla planivolia) vines[, ].
Loppings of the plant provide a quickly decomposing green manure, containing per 100 g dry matter: N 1.5-3 g, P 0.2-0.35 g, K 1-2 g[].
Most Erythrina species are very easy to grow from cuttings, with even quite large branches striking well. In addition, they generally fix atmospheric nitrogen, have nutrient-rich leaves that make an excellent soil-enriching mulch, often have open crowns that do not overly restrict light, and are also often quite thorny and can provide impenetrable barriers to protect from unwelcome intrusions. Many species are therefore used as living fences to provide boundaries and livestock-proof hedges[, ].
The tree is planted as a pioneer species in northern Thailand in reforestation projects to restore native woodland - it is planted in degraded woodland and open areas in a mix with various other species that all have the ability to grow fast; produce dense, weed-suppressing crowns; and attract seed-dispersing wildlife, particularly birds and bats[].

Other Uses

The wood is soft, light and coarse-grained, the texture coarse and uneven[]. The sapwood is not differentiated from the heartwood, which is light straw-coloured[]. It is utilized in canoe and raft building[, ].

Propagation

Fresh seeds, and those harvested within 3 - 6 months of maturity, can be sown without any special treatment. Germination rates are generally high and are often 100%. Seeds over 6 months old may take between 12 - 18 months to germinate due to their hard seed coat which becomes tougher with age. Soaking them in hot water, or abrading their seedcoat, can reduce this time considerably. They may be added to water which has just fallen below boiling point and left in the water as it cools for a minimum of one hour, but up to 12 hours for seed 3 years or more old, and then sown in the usual way. Alternatively, file the seeds with a slender triangular file. A groove can be made through the sides of the seed coat with care so as to avoid damaging the cotyledons or embryo, which usually results in the death of the seeds from fungal attack or in malformed and weakened seedlings[].
Seeds of most species produce strong seedlings from healthy seeds in almost any well-drained soil, with a minimum of trouble from damping-off disease[].
The plant can be propagated by seed, but seeds from thornless trees generally produce trees with thorns[].
Large cuttings, even if they are 25 cm in diameter, usually root easily[].

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