Cordia (subcordata)

Kim Wilkinson Craig Elevitch Permanent Agriculture Resources P.O. Box 428 Holualoa, Hawaii 96725 808-324-4427 808-324-4129 (fax) par@agroforestry.net www.agroforestry.net

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Family Scientific Name:	Boraginaceae
Family Common Name:	Borage
Scientific Name:	Cordia subcordata Lam.
Common Name:	Sea trumpet, beach cordia; kou (Hawaii), nawanawa (Fiji); puataukanave (Tonga); tuanave (Samoa); tou (Cooks, Societies, Marquesas)
Ecotype:	low elevation, dry, coastal areas
General Distribution:	Native to Malesia, spread throughout the Pacific and along Indian Ocean Shores. Once thought to be a Polynesian introduction to Hawaii, but recently discovered fossil evidence now indicates this tree is native to Hawaii.
Known Invasiveness:	This species is widely introduced throughout other tropical regions of the world where it may be invasive in some areas and invasiveness outside its naturally occurring range is unknown.
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Time To Grow:	6 Months
Target Specifications:	Seedlings have reached target when approximately 35 cm in height, stem diameter 9 mm, with well-formed root systems that are not root-bound but that fill out the container.
Propagule Collection:	Blooms throughout the year, most abundantly in the spring. Seed capsules are often collected from the ground, but can also be picked from the tree once mature(dry and brown).
Propagule Processing:	Recommendations for storing seed are unavailable. It is thought that the seeds can retain some viability when stored in airtight containers, though fresh seed is recommended. The fruits (capsules) are about 2.5 cm long, and contain up to 4 soft, white seeds. Because the seeds are very difficult to extract without damage, whole capsules are sown.
Pre-Planting Treatments:	No pretreatment is required. However, germination can be hastened by cutting off one end of the seed capsule and soaking 12-24 hours prior to sowing.
Growing Area Preparation/ Annual Practices for Perennial Crops:	Kou seedlings can be grown in an uncovered growing area. If available, some cover (greenhouse or temporary cover) is ideal during germination to protect sprouts from hard rains. Rodents (especially rats) seek out and eat germinating kou seeds, and the nursery area must be protected from them. Containers used are Andersen Band Pots 2 3/8" by 5" inches deep, although copper-coated grow bags or similar size also work well. A well-drained media such as 50% Sunshine peat moss, 25% perlite, 25% vermiculite, amended with a little compost, dolomite lime, gypsum, and slow-release fertilizer such as osmocote 14-14-14. Potting media should also be inoculated with VAM (mycorrhizal fungi), available from commercial suppliers and garden centers.
Establishment Phase:	Seeds are sown at a depth of 1.5 - 2 cm. Because multiple seeds usually germinate per capsule, a germination bed can be used, then small seedlings transplanted into the growing containers. Germination begins in 3-4 weeks. Seed capsules break apart begin to decay as the germinating seeds sprout. Transplants of seedlings at the cotyledon phase can be made. Even tiny germinants transplant well, when they have a short root (about 5 mm) and before the cotyledons turn green. Once germinants have been transplanted into containers prefilled with premoistened media, the media can be topped by a thin layer of mulch such as from #2 poultry grit. Water with a fine-headed sprayer to keep moist. Full sun is best. Daily water is usually necessary, by hand or with an automated system.
Length of Establishment Phase:	2-3 weeks
Active Growth Phase:	Seedlings can be grown in full sun. Seedlings grow slowly for the first 6-10 weeks, then grow rapidly. Overwatering can lead to fungal diseases on the leaf and stem. A coastal environment for growing may help preclude some fungal problems in the nursery. In wetter areas or higher elevations, cultural practices can reduce problems with fungal pathogens. After about ten weeks, seedlings are spaced as widely as possible to prevent leaves from overlapping and to allow maximum penetration of sunlight, which creates an environment more hostile to fungal pathogens. Watering first thing in the morning is best, so leaves spend most of the day dry and go into the night dry. In some cases, amending with additional fertilizer such as a light top dressing of Gro-More 8-8-8 will aid in growth and development. If any weeds enter the soil-free media, they should be removed.
Length of Active Growth Phase:	4-6 months
Hardening Phase:	Growers should continue to ensure that seedlings receive full sun, spacing seedlings out further if necessary. Seedlings should never be allowed to dry out, but watering frequency may be reduced to introduce seedlings to temporary, moderate water stress.
Length of Hardening Phase:	4-6 weeks
Harvesting, Storage and Shipping:	When seedlings have reached target size, they may be delivered to the planting site. They are not extracted from their container or stored before shipping. Keeping them in their container is necessary to protect the roots. Containers may be stood up in cardboard boxes, or delivered in trays. Seedlings must be protected from wind and excessive heat during transport, but refrigeration is not recommended. Empty containers and trays may be returned after the planting is complete.
Length of Storage:	n/a
References:	National Tropical Botanical Garden (NTBG). 1996. Ten native Hawaiian trees for urban landscapes. Lawai, Hawaii. Vozzo, J.A. (Ed). 2002. Tropical Tree Seed Manual. USDA Agriculture Handbook 721. Wagner, Warren L., Darrel R. Herbst, and S. H. Sohmer. 1990. Manual of the flowering plants of Hawai'i. 2 vols., Bishop Museum Special Publication 83. University of Hawaii Press and Bishop Museum Press. Honolulu.

Citation:

Elevitch, Craig R.; Wilkinson, Kim M.. 2004. Propagation protocol for production of Container (plug) Cordia subcordata Lam. plants Permanent Agriculture Resources Holualoa, Hawaii. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/07/01). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.