Metrosideros (polymorpha)

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:	Myrtaceae
Family Common Name:	Myrtle
Scientific Name:	Metrosideros polymorpha Gaud.
Common Name:	`ohi'a, `ohi'a lehua, lehua
Ecotype:	wide range of mesic to wet forest, near sea level to 2,200 m
General Distribution:	Endemic to the Hawaiian Islands, present on all main islands except Niihau and Kahoolawe.
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Time To Grow:	0
Target Specifications:	25 cm height, 10 mm stem diameter
Propagule Collection:	Collect seeds from trees in the same region as will be planted. Flowering may take place on individual trees any time of year. The primary flowering season is late spring and summer, although this varies between populations. The tiny seeds are borne in capsules which swell when mature, showing lines where the capsule will soon split open. Collect capsules just before they begin turning brown (before the seeds are released and disperse in the wind). Fruits mature 70 - 90 days after flowering. Collect by hand or with pole pruners.
Propagule Processing:	After collecting mature but still closed capsules, allow them to air dry in an open container or paper bag. The tiny seeds will readily fall out of the capsules after a few days. There are about 1,700,000 seeds per kg. The seeds typically have germination of 50 -60 %, but some seed lots may have lower germination rates. Seeds quickly lose viability, so sowing within a few weeks of collection is recommended. Store seeds refrigerated in a paper envelope in an airtight container with desiccant. It has been reported that germination dropped to 10% after a year of storage.
Pre-Planting Treatments:	No pretreatment is necessary.
Growing Area Preparation/ Annual Practices for Perennial Crops:	A rain protected but light area is necessary for germination in trays (such as a cold-frame with clear film roof). After the germination and early establishment phase, full sun is recommended for growing out the individual seedlings in containers. Andersen Band Pots 2 3/8" by 5" inches deep or other root-training containers of similar or greater volume (164 ml) work well. A well-drained potting media such as 50% Sunshine peat moss, 25% perlite, 25% vermiculite, amended with a little compost, dolomite lime, gypsum, and micronutrients and slow-release fertilizer such as osmocote 14-14-14 is used. Potting media should also be inoculated with VAM (mycorrhizal fungi), available from commercial suppliers and garden centers. Once the seedlings reach 15-25 cm, they can be moved up to one gallon root training containers, or outplanted.
Establishment Phase:	The tiny seeds of `ohi'a should be started in trays and later transplanted to individual growing containers. Sprinkle the seeds over fine commercial potting medium, black cinder, sterile compost, or vermiculite, as preferred. Covering the seeds is not recommended. However, the medium must be kept moist with a very fine mist sprayer so as not to disturb the tiny germinants. Alternatively, the trays can be placed in larger shallow trays filled with water keep the medium moist from below. Germination temperature of 72 degrees F is ideal. Some light (not full sun) is recommended to improve germination. Germination takes 7 - 14 days for fresh seed, longer for older seed (4 - 6 weeks for one year old seed. When the seedlings have reached the 4-leaf stage (about 2 - 3 cm tall), transplant to individual containers.
Length of Establishment Phase:	6 - 8 weeks
Active Growth Phase:	Seedlings should be grown in full sun. Keep seedlings well spaced apart to allow maximum penetration of sunlight and air circulation. 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.
Length of Active Growth Phase:	8 months
Hardening Phase:	Space 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. If fertilization is necessary during the hardening phase, N fertilizer should be minimized or eliminated, with emphasis on P, K, and micronutrients.
Length of Hardening Phase:	6 - 8 weeks
Harvesting, Storage and Shipping:	When seedlings have reached target size, they may be delivered to the planting site. Keeping them in their containers help protect the roots and allows the plants to stand up in cardboard boxes. Seedlings must be protected from wind and excessive heat during transport, but refrigeration is not recommended. Cutting the pot off (rather than pulling the plant out of the pot) will help reduce root damage during transplanting.
References:	Bornhorst, Heidi L. 1996. Growing native Hawaiian plants: a How-to Guide for the Gardener. The Bess Press, Honolulu. Little, Elbert L. and Roger G. Skolmen. 1989. Common Forest Trees of Hawai`i (Native and Introduced). United States Department of Agriculture Forest Service, Agriculture Handbook 679. National Tropical Botanical Garden (NTBG). 1996. Ten native Hawaiian trees for urban landscapes. Lawai, Hawaii. University of Hawaii College of Tropical Agriculture and Human Resources. 2001. Hawaiian Native Plant Propagation Database. Honolulu, HI. Web: http://www2.hawaii.edu/~eherring/hawnprop/met-poly.htm Allen, J. 2002. "Metrosideros Polymorpha Gaudich." In: Vozzo, J.A. (Ed). 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.. 2003. Propagation protocol for production of Container (plug) Metrosideros polymorpha Gaud. plants Permanent Agriculture Resources Holualoa, Hawaii. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/07/02). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.