How to Grow an Ohia Tree

Selecting a Growing Location

Avoid locations with high altitudes. Do not plant an Ohia tree over 9,000 ft (2,743 m) in elevation. Ohia trees are not suited for high elevations, and will likely wilt and die if planted too high. Higher elevations likely have too little oxygen in the atmosphere to sustain an Ohia tree, and may not have enough humidity. If you live in an area above 9,000 feet (2,743 m), consider finding a different species of tree to plant.

Choose an area that gets full sunlight. Ohia trees need near-constant sunlight during daylight hours, and so should be planted in an open space that affords plenty of light. Do not plant your Ohia tree near a large wall or building that will block the sun. Similarly, do not plant the Ohia near a larger tree or bush whose foliage will prevent sun from reaching the Ohia. Young Ohia trees and bushes that have not fully grown may prefer partial sun (about 6 hours of sun exposure a day), until they reach maturity. If your Ohia is in the ground, you won’t be able to change its sun exposure as it matures because it dislikes root disturbance. However, if the Ohia tree is in a planter, you can move the planter to keep the juvenile tree in partial sunlight.

Make sure that your soil has good drainage. Ohia trees will become unhealthy if the soil they are planted in becomes saturated and waterlogged. To avoid this problem, plant your Ohia in a soil with good drainage. The soil should also be rich in organic material, which will nourish the growing Ohia tree and keep it healthy. You can purchase a planting soil mixture at your local hardware store, or at a local plant nursery or gardening center. Ask the sales staff for assistance, and request that they help you find a soil that drains well.

Planting Your Ohia Tree

Purchase Ohia seeds or a seedling. Unlike various other tree species, Ohia trees can be grown from seeds relatively easily. If you live in Hawaii, you should be able to purchase Ohia seeds or a small seedling at a local plant nursery or gardening center. If you live elsewhere, you can order Ohia seeds online. Check with plant retailers that specialize in Hawaiian flora, including Maui Native Nursery and Kauai Seascape nursery. The seeds of the Ohia tree are tiny, and a cluster of them may look like a small pile of dust. These seeds grow in ¼-inch (0.65 cm) pods on the Ohia tree. The seed pods burst open when they have matured, and allow the seeds to disperse.

Plant your Ohia seeds. Fill any size planter with a planting soil mixture, and lightly sprinkle the tiny Ohia seeds on top of the soil. Ohia seeds will grow best if exposed to plenty of sunlight, so place the planter outdoors, away from shade. Water the seeds lightly at first, with a spray bottle, until they start to sprout. Even if you’re unable to place the Ohia seeds in full sunlight, they’ll likely still grow. The seeds are tough and can grow in practically any light conditions. The seeds will grow best between 50°F and 93°F (10–34°C). If the outdoor temperatures dip below 50 or climb above 93, bring the plant indoors to more stable temperatures.

Plant an Ohia cutting. If you can obtain a cutting from an Ohia tree in your area (perhaps from a tree owned by a friend or family member), you can use this to grow your own Ohia. Plant the Ohia cutting in soil that is porous and drains well, so the cutting isn’t drowned by repeated waterings. If the cutting is too small to stand erect in a pot full of soil on its own, you can stick a large dowel in the soil and tie the cutting to the dowel using thread. Take your cutting from the stem or branch tips of a mature Ohia tree. The cutting that you plant should be about 4-6 inches (10-15 cm) in length, and ¼-inch (0.65 cm) in diameter. A cutting will take time to begin establishing its own roots: at least a week or two.

Re-plant an Ohia cutting or seedling into rich soil. Once the young Ohia tree (whether grown from seeds, a cutting, or a seedling) has begun to grow, you’ll need to transplant it from a pot directly into the ground. Ohia roots need to be able to absorb water but should never become waterlogged, so plant the tree in soil that drains well and is not prone to forming puddles. Ohia trees grow quickly, and will become root-bound if left in a pot for too long. Put the plant in soil in the ground as soon as it grows large enough to encourage healthy growth, or about 1 foot (0.3 meters) tall.

Dig a hole that is twice as wide as the root ball. The Ohia roots will have sufficient room to expand in a hole of this size. Make the hole roughly the same depth as the root ball, so that the trunk of the seedling will not be buried once it’s planted. While you’re digging, turn the soil by breaking apart clumps, removing rocks, and flipping the shovelfuls of soil upside down so that the organic material can be worked through the soil. For added soil drainage, place a couple of cinder blocks at the bottom of the hole to allow for soil drainage. You should be able to purchase cinder blocks at a local hardware or landscaping store.

Place the seedling in the hole and cover it with soil. Once the cinder blocks are firmly in place, gently set the Ohia tree in the hole and cover the roots with a rich soil mixture. Be sure not to cover the base of the trunk with soil.

Caring For an Ohia Tree

Water and fertilize the Ohia tree. Ohia trees thrive in tropical environments, and consequently need to be watered often. Plan to water your Ohia tree at least once a week, using water from a household hose. In order to keep the tree healthy and encourage its growth, you can also apply a fertilizer. Purchase an 8-8-8 or 13-13-13 fertilizer, and apply it to the base of the Ohia tree once every six months. Hours after watering, make sure that the soil is draining well. You should not see any puddles around the base of the Ohia tree, and the soil should be damp but not saturated.

Avoid planting an Ohia tree near doors or openings to your home. Plant the tree at least 10 feet (3 meters) away from your doors, garage door, or windows that you enjoy leaving open because the tree will attract bees, wasps, and other insects. While they are merely there to pollinate the tree, you will want to avoid having them enter your home. If large numbers of bees or wasps are frequently in the tree, they may fly into your house if the tree is near an opening.

Plant multiple Ohia trees near one another. If you’re planning on growing more than a single Ohia tree, you don’t need to worry about giving the trees plenty of space in every direction, as with some other species. Ohia trees can grow well while crowded together. Plant multiple Ohia trees with as little as about 5 feet (1.5 meters) between their trunks. Over the years, as the Ohia trees grow, you may decide to prune some of the trees’ branches. Prune using a pair of pruning shears, in cases where branches from two Ohia trees overlap.