UHWO Botany: Native Plant Propagation Update

Earlier this semester, my botany students prepared and planted their own native Hawaiian plant to use in our restoration at Piliokahe Beach this coming April. The students cared for their baby plants at home for about two months. This week, we brought them back to see how much they’ve grown! Below are the plants prior to planting (left) and after two months of student care (right). We planted pa’u o hi’iaka, ‘akulikuli, and pohuehue (left-to-right in the photo below).

I planted an ‘akulikuli, which I photographed throughout the 2-month propagation window. One of the steps in our planting protocol was to remove any secondary stems in the bottom few centimeters of the primary stem. This provides a length of bare stem to plant underground where roots will develop. Buried secondary stems would likely rot and potentially introduce disease into the plant. I saved a couple of these secondary stems and propagated them hydroponically so we could estimate root development in our plants without having to disturb their root systems. Since I did *not* dip my secondary stems in the rooting hormone, these served as a lower estimate to the root development we expected in our plants.

My little ‘akulikuli is growing up!

Root estimator

By the second week, we had roots and flowers

Unfortunately, we had a lot more mortality than I had hoped…. The pa’u o hi’iaka suffered the worst, with ~90% mortality. Only one of the nine pa’u o hi’iaka that we propagated survived (shown below with its successful caretaker, Shayna). The other species fared a little better: 50% the ‘akulikuli (2 out of 4) and 75% of the pohuehue (6 out of 8) survived, giving us an overall survival rate of ~40%.

 

Shayna and her lone successful pa’u o hi’iaka

The good news is, the ones that survived are in very good shape. On average for the pohuehue, we had a 7 cm increase in height, and an increase of 11 leaves. The ‘akulikuli saw an average 4 cm increase in height and an increase of about 45 leaves. Our lone pa’u o hi’iaka increased 5 cm in height and gained 5 leaves. Our restoration expert, Bruce Koebele, will care for the plants until they are planted in their new home at Piliokahe Beach on April 9th.

6 pohuehue (back 2 rows), 2 ‘akulikuli (front left), and our 1 lone pa’u o hi’iaka (front right)

We even attracted a little stow-away.