Pahole Rare Plant Facility – FY 2007 Report


The objectives of the Pahole Rare Plant Facility (PRPF) are listed below. Priorities will shift as propagation material is available and as plants are reintroduced, but should follow the order given here.

  1. Provide facilities for the ex situ cultivation/storage of mid-elevation species (priority to species with less than 50 individuals in the wild) that cannot be stored as seed or in tissue culture.
  2. Propagation of rare plants for reintroduction from Oahu as needed for land managers with protected habitats.
  3. Production of more common native species for restoration efforts, provided time and resources are available and the operation is self-supporting.


Provide facilities for the ex situ cultivation of Plant Extinction Prevention Program mid-elevation species (less than 50 individuals in the wild) that cannot be stored as seed or in tissue culture, with priority to Oahu species.

Work on the new 2500 square foot greenhouse continued through FY 2007. Structural elements of the greenhouse are built; shading, walkways, benches, and irrigation projects are underway and will be completed in FY 2008. Foundation and groundwork for this new greenhouse was finished in the spring of 2007. This work included filling and compacting of the sub-grade, installation of a drainage system under and around the footprint of the greenhouse, and final grading of the site prior to construction. This work was done by the NARS Manager, the NARS Field Project Specialist, and the PRPF Horticulturist. Setting of the poles and erecting the structure of the greenhouse was done by personnel of the Army Environmental Program.

The PRPF is dependent on catchment water for all of its water requirements. Installation of a new gutter system that was started late in FY 2006 was completed early in FY 2007. Completion of this project has optimized PRPF’s ability to catch rainwater. The third large water storage tank that was purchased in FY 2006 was installed, connected to the main water line system, and put into use in FY 2007. Foundation and groundwork for this water tank was done by the NARS Field Project Specialist and the PRPF Horticulturist. Installation of this tank was done by a private company contracted for the job. Completion of this third tank gives PRPF 62,000 gallons of long-term water storage. Further development of the water catchment system is to one of the two aging polyethylene holding tanks at each of the two PRPF buildings. A replacement tank for the lower building has been purchased and will be installed in FY 2008.

Propagation of rare plants for reintroduction from Oahu as needed for land managers with protected habitats.

A total of 2,457 plants were grown at PRPF during FY 2006 for restoration and living collections. The species included: Abutilon sandwicense 16, Alectryon micrococcus var. micrococcus 3, Bobea sandwichensis 1, Bonamia menziesii 6, Caesalpinia kavaiensis 34, Chamaesyce deppeana 4, Chamaesyce herbstii 18, Colubrina oppositifolia 167, Cyanea crispa 2, Cyanea grimesiana subsp. grimesiana 10, Cyanea grimesiana subsp. obatae 69, Cyanea longiflora 17, Cyanea superba subsp. superba 120, Cyanea truncate 36, Cyrtandra dentata 7, Cyrtandra kaulantha 16, Cyrtandra polyantha 61, Cyrtandra subumbellata 13, Delissea subcordata 157, Dubautia herbstobatae 57, Eugenia koolauensis 4, Euphorbia haeleeleana 7, Eurya sanwicensis 1, Flueggea neowawraea 24, Gouania vitifolia 105, Hedyotis degeneri var. degeneri 1, Hedyotis parvula 2, Hesperomannia arborescens 1, Hespermannia arbuscula 20, Labordia cyrtandrae 6, Lobelia monostachya 17, Melanthera tenuifolia 108, Melicope lydgatei 2, Neraudia angulata 100, Nototrichium humile 112, Phylllostegia hirsuta 15, Phyllostegia kaalaensis 224, Phyllostegia mollis 50, Phyllostegia parviflora var. lydgatei 27, Plantago princeps var. princeps 4, Pritchardia kaalae 170, Pritchardia remota 31, Psychotria hexandra ssp. oahuensis 2, Scaevaola coriacea 35, Schiedea adamantis 54, Schiedea kaalae 56, Schiedea nuttallii 83, Schiedea obovata 40, Silene perlmanii 21, Stenogyne kaalae subsp. sherffii 65, Stenogyne kanehoana 114, Syzygium sandwicensis 1, Tetramolopium filliforme 15, Tetraplasandra lydgatei 28, Urera kaalae 8, and Viola chamissoniana subsp. chamissoniana 90. (Total 2,457 plants)

The primary cooperator for outplanting of the threatened and endangered plants grown at PRPF is the State of Hawaii’s Oahu Plant Extinction Prevention (OPEP) Program. There are currently 28 OPEP species being grown at PRPF, these plants are either for future outplanting or living collection plants. PRPF supplied 226 plants of eight species for the 2007 OPEP program outplanting season.

During the summer of 2006 PRFP was fortunate to have a UH Hawaiian Internship Program intern. One of her projects for the summer was to investigate the possibility of using leaves to propagate a variety of species in the genus Cyrtandra. It is common practice to propagate plants in the family Gesneriaceae using leaves, but it was not known if Hawaiian endemic genus Cyrtandra could be propagated with this method. Through the work that was done with this project, leaf propagation is a viable propagation method for Cyrtandra. Sixteen plants of Cyrtandra kaulantha were produced by this project; the leaves that produced these plants were harvested, treated, and planted on June 21, 2006. Many of the leaves had produced plantlets and were transplanted to individual pots by September of 2007. These plants are being grown at PRPF and are ready for outplanting.

In cooperation with the NARS specialist, a propagation project with Colubrina oppositifolia was begun in March 2006, and is on-going. Through numerous collections from a number of populations PRFP has learned what the staff feel is the optimum cutting material and the best post collection handling techniques. Early collections had very low cuttings rooted percentage and a moderate number of individuals that failed to produce any rooted cuttings. Through experience gained, the more recent collections have yielded much better rooted cutting percentage and all individuals collected have produced at least one rooted cutting. These plants are growing very well. To date, PRPF have 166 plants representing 38 founders.

Production of more common native species for restoration efforts, provided time and resources are available and the operation is self-supporting.

Both the NARS and OPEP staff have been encouraged to collect seed and cuttings of common natives so the staff can propagate them and have them on hand so they can incorporate these plants in their habitat restoration efforts. PRPF is currently growing seedlings of Acacia, Bobea, Hedyotis, Diospyros, Psychotria, Santalum, Sapindus, and Pisonia. PRFP also has rooted cuttings of Isodendrion and several species of Hibiscus.