The Supply Trail is a 4.6 mile in and out hike that leads from the Hosmer Grove parking area to the Halemau’u Trail which then heads into the Crater.
Hosmer Grove is located just after the park entrance; turn left at the first road. There will be a dip in the road and parking just after.
After parking walk back along the road towards the dip. A large Mamane, with its gray-green, pinnate leaf is on the left and is surrounded by Pukiawe and Ohelo shrubs. The Pukiawe has stems clothed tightly with small, short pointed leaves and often has pink or white berries. The Ohelo have delicious fruits (must be ripe) and new growth that is bright red.
At the start of the trail, on the right is a very large Pilo, than the most common plant is Pukiawe. Around all the shrubs is the Hawaiian Bracken Fern, Kilau (deciduous in winter). Also there are many Mamane and Ohelo with the Mamane beginning to bloom in December and January.
Keep an eye out, on the right, for Kukanene, another the low growing Pilo, with dark green needle-like leaves and shiny black berries.
You also begin to see a few plants tagged with yellow, blue, orange and white tape. These mark the site of traps that the Ranger’s have set out to control the Hawaiian Rat.
At a clearing there is another nice Sandalwood on a rise to the left. It is a rounded shrub with dark green foliage.
I’m in luck today, a Pueo, the Hawaiian Owl, flies by low on the left. I will see him again circling above and with my binoculars see his unique face.
The trail climbs toward the summit road. The Pilo here have a few orange berries. It’s a real treat when the bush is loaded with fruit.
On the right, about 40’ away is an aged Ohia flanked by several Aalii. This venerable specimen is not of great height but when I got close and looked I found a great gnarled trunk.
With the road in sight we come to a gulch with a lava waterfall, and today there is water there. In the black lava gulch are many Aalii, Mamane, the hairy stemmed Laukahi Fern, more Kukaenene spilling over the lava rock and a few Kupaoa with their large, clasping green leaves and yellow orange flowers.
As we leave the gulch a native bunching grass appears, Gahnia with its stiff Carex-like leaves and brown seedpods. The trail climbs and than veers left following the gulch. The shiny gray leaves of Nohonau, a native Geranium begins to appear among the other shrubs. The tips of the gray leaves are notched, like a trident, and white flowers appear summer through fall.
As the trail nears the edge of the gulch look for the bright green leaves of Kupaoa. The large clasping leaves are alternate on the stem every 90 degrees. You can’t quite reach them but their leaf color and shape do stand out.
The trail crosses the gulch at another lava waterfall than veers left some and climbs again. There is a young 2’ high Sandalwood on the left side. It’s good to see new young plants. On the right in the shady side of a 5’ lava rock is a small native fern, Maiden Hair Spleenwort. I have actually grown this at the Getty and was surprised to learn that it’s home is at such a high elevation.
As the trail cuts across the hillside, about 100 yards below the road, amazing views come into play behind to our left. The West Maui Mountains and Molokai in the distance appear on clear days. Ahead there is a water tank in the distance, the trail will go up and around it.
An old lava rock wall comes into view; this is probably a boundary marker from the old ranch days. There are many Ohia in this area, some growing right next to the wall. The trail passes through the wall and then crosses over another lava gulch, this one quite shallow.
More bird luck comes my way as the sound of chirping gets me to bring the binoculars into play and I see an Amakihi, a small rounded native bird with a yellow green breast coat and a short curved bill. This bird is omnivorous enjoying insects and spiders as well as nectar.
Farther on a left turn in a switchback is another small native fern, Iwaiwa. (Note: there is more than one native fern with this common name) I’ve been watching this fern for many years and its always there when I pass by.
The trail levels out some and views down into Koolau Gap on the left. Invasive Pines are on the top but native forest has the valley floor.
At 2.3 miles we reach the Halemau’u Trail, enjoy our success and head back down the supply trail.