Pittosporum species

photo credit: Forest and Kim Starr

Best practices for survivability and field observations

One respondent observes that “its thick leaves should do well in dry/mesic environments, although hōʻawa is not considered coastal (except for P. halophilum from Moloka‘i which can handle salt exposure).” Another agrees, saying that although “there are many species and it is hard to generalize, most species will handle most low elevation settings (P. hosmeri, P. glabrum, and P. halophilum, a shrub, endangered coastal form).” The same person observes that P. flocculosum is found only on O‘ahu and P. confertiflorum grows in drier forest types. Another notes that it can create a “good shape for visual barrier or hedge” even if it is “moderately slow growing.” One notes that hō‘awa do well in South Kona (2000′ elevation), while another noted 0% survival rate at Kealia Pond (species of hōʻawa is not known).  Cultural uses are for medicine and dyes.

Stressors and pests

All species seem susceptible to drought, yet P. argentifolium, P. confertiflorum, and P. terminalioides, P. halophilum (extremely rare plant from Moloka‘i only) appear more drought tolerant while P. hawaiiense appears less so. One respondent notes that P. hosmeri, P. glabrum, and P. halophilum (shrub, endangered coastal form) are relatively “trouble free.”  Although endangered, several recommend P. halophilum for lowland coastal plantings. P. glabrum and P. argentifolium are susceptible to scales and require more moisture. Goats and/or deer will eat seedlings and younger plants (P. glabrum in particular)

Availability and propagation

Limited availability. For example: P. cauliflorum is drought tolerant but limited in availability. Propagation is mostly by seed. For P. confertiflorum and P. glabrum obtaining the fruits and seeds at the right time is crucial. P. hosmeri is easy to grow from seed.

Survey Results

For information about the survey, refer to our article: on Coastal Plants for Creating Green Breaks