Notes on Propagation and Cultivation of Erythrina in Hawaii

Abstract

Successful methods of propagation from seeds and by cuttings for Erythrina species are described. Species cultivated in the Waimea Arboretum, Haleiwa, Hawaii are listed, and information on their flowering periods is given. Erythrina may be propagated easily from seeds, by cuttings or air layers, and probably also by grafting. In Hawaii, propagation from seeds and by cuttings are the most commonly used techniques. PROPAGATION FROM SEEDS 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 and 18 months to germinate due to their hard seed coat which becomes tougher with age. They need to be specially treated by one of the following methods to hasten and improve germination. They may be dropped into water which has just fallen below boiling point and left in the water as it cools for a minimum of one hour. If the seeds are three years old or more, they should be left to soak in the water for 10 to 12 hours and then sown in the usual way. As this method can kill the embryo if the seed coat is not very hard, it is preferable to 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 welldrained soil, with a minimum of trouble from damping-off disease. However, as it is difficult to obtain seeds of many of the rarer species, it is wise to use a partially sterilized soil and to add sand and peat. Some gravel, or cinder as is used in Hawaii, ensure drainage and rapid root growth. Air movement around the seedlings is beneficial. A similar soil mixture, without sterilized soil, can be used for potting. The first potting of seedlings can be carried out when they are 5-8 cm high. Shade is essential for their survival during the first few days. Species successfully germinated are indicated in Table 1. PROPAGATION BY CUTTINGS Propagation by cuttings can be rapid and successful depending on the species used, the time of propagation, and the maturity of the wood. At Waimea Ar'I am indebted to Mrs. Ann Prance for reading and checking the manuscript. 2 Horticulturist, Waimea Arboretum, Haleiwa, Hawaii 96712. ANN. Missoum BOT. GARD. 66: 541-544. 1979. 0026-6493/79/0541-0544/$00.55/0 This content downloaded from 207.46.13.115 on Sat, 08 Oct 2016 05:24:32 UTC All use subject to http://about.jstor.org/terms TABLE 1. Records of germination of seeds and/or propagation by. cuttings of Erythrina at Waimea Arboretum, Haleiwa, Hawaii.'