10-23-2007, 06:25 PM
Aloha Joey,
Ironwoods are considered a serious invasive coastal pest in Hawai'i. There is a chemical in their needles that is reportedly toxic to other plants and will prevent anything else from sprouting. When the layer of needles gets thick enough the ground underneath it becomes a "biological desert". I wouldn't use the needles for mulch at all.
In fact, you might consider coming up with a plan to slowly replace then with a more diverse and interesting canopy of coastal trees. I say "slowly replace" because they do provide welcome shade in areas where they have displaced the native trees and other vegetation. If you are close to the ocean, some fast growing native trees to try are kamani, milo, kou, hau and hala (for areas away from walkways). Just as an experiment try and remove some of the needles revealing the soil underneath and see if anything comes up in there. If it does, then you can use the soil, but if not (as is my guess) you may need to add pockets of soil to plant anything else. In my opinion, the best soil mix is 1/3 cinder, 1/3 soil (could be sand or hamakua sugar "soil" and 1/3 organic compost. Mac nut husk compost is good for that if you can get it. "Cinder soil" is most of the time about 1/2-3/4 cinders mixed with some organic material (usually mac nut husks). There is also "dump mulch" which is basically all kind of trees that are chipped at the dump in an un-decomposed state. You can use it as mulch but I wouldn't mix it into soil. It's also full of weed seeds and bugs when fresh.
Aloha,
Mitzi
Uluhe Design
Native Landscape Design
uluhedesign@yahoo.com
Edited by - Mitzi M on 10/23/2007 22:26:29
Ironwoods are considered a serious invasive coastal pest in Hawai'i. There is a chemical in their needles that is reportedly toxic to other plants and will prevent anything else from sprouting. When the layer of needles gets thick enough the ground underneath it becomes a "biological desert". I wouldn't use the needles for mulch at all.
In fact, you might consider coming up with a plan to slowly replace then with a more diverse and interesting canopy of coastal trees. I say "slowly replace" because they do provide welcome shade in areas where they have displaced the native trees and other vegetation. If you are close to the ocean, some fast growing native trees to try are kamani, milo, kou, hau and hala (for areas away from walkways). Just as an experiment try and remove some of the needles revealing the soil underneath and see if anything comes up in there. If it does, then you can use the soil, but if not (as is my guess) you may need to add pockets of soil to plant anything else. In my opinion, the best soil mix is 1/3 cinder, 1/3 soil (could be sand or hamakua sugar "soil" and 1/3 organic compost. Mac nut husk compost is good for that if you can get it. "Cinder soil" is most of the time about 1/2-3/4 cinders mixed with some organic material (usually mac nut husks). There is also "dump mulch" which is basically all kind of trees that are chipped at the dump in an un-decomposed state. You can use it as mulch but I wouldn't mix it into soil. It's also full of weed seeds and bugs when fresh.
Aloha,
Mitzi
Uluhe Design
Native Landscape Design
uluhedesign@yahoo.com
Edited by - Mitzi M on 10/23/2007 22:26:29
Uluhe Design
Native Landscape Design
uluhedesign@yahoo.com
Native Landscape Design
uluhedesign@yahoo.com