- Author: Jenni Dodini
Being a little bit retired has allowed Steve and me the luxury of travel. In that vein, we decided to celebrate our anniversary on the "Big Island" this year. Driving to the hotel, I noticed what looked like clumps of some kind of grass growing up from the lava rocks all over the place. For those of you unfamiliar with Hawaii Island, it has 11 of the 13 known climates in the world, all contained on one fairly good sized island which was formed by volcanic activity. One side of the island, the Kona side, is dry; 10 inches average rainfall per year. Then the other side, the Hilo side, gets LOTS of rain, like 200 plus inches per year.
I imagine you are now wondering where I am going with this blog.
Here it is. We went on a tour. (No surprise there.) So, it was asked, "what is this plant growing up from the lava rock?" As one can expect from a professional tour guide, he had a story about it. It is known in Hawaii as African Fountain Grass. It was brought to the island by a well meaning home gardener looking to beautify the garden with a plant that could withstand the environment of that particular home. What happened is that this plant quickly became invasive all over the island and is now threatening the native plants in the island that are crucial in reforesting in the lava flow areas. It is also beginning to threaten the coffee trees! Really unacceptable.
So, true to my nature, I had to stew about this information. Then I had to look it up. The African Fountain Grass is from the family Poaceae, and this variety is Pennisetum setaceum. There is a variety which is becoming invasive in California as well. According to the Hawaii Invasive Species Council website, it is classified as Hawaii's most invasive ornamental plant. It is posing a serious risk to the island because it out-competes other plants for available resources, like water and space. It also adapts very easily to whatever environment into which it is introduced. It is native to Africa and the Middle East, grows in clumps up to about 3 ft in height, has long wiry leaves and the flowers and seeds form long purple or yellow spikes. The seeds are easily dispersed by the wind and water, as well as animals and vehicles. The most concerning thing about this plant is that it has adapted to fire. It can survive a brush fire even though it is an excellent fuel for a brush fire. According to the information on the Hawaii site and the Invasive Grasses site at which I looked, it seems that fire actually stimulates its growth!!! This is a very nutritionally poor grass, so much so that the cattle and wild sheep and goats will not eat it unless there is absolutely nothing else to eat. What is happening on Hawaii Island, and probably also in California, is that this grass is changing the structure of the "dry forest" to a grass savannah. This grass is incredibly difficult to control as you can easily see from the picture below. The only way is to pull it out when it is small or whack it down with a weed whacker before it can flower and seed, or dig it out. Then there is a very strong herbicide but the fear is that it will adapt and become resistant.
My thoughts have been veering along the path of "I hope that I have not been that kind of home gardener" to "I need to do what I can to avoid becoming that kind of gardener" then further down the path to "what can I, as a Master Gardener, do to prevent others from introducing an invasive species into our environment?"
I hope that this blog becomes Food For Thought about what we can do when we meet the public out there.