Each berry can contain 100 sand grain-sized seeds. Therefore, a single mature tree can produce approximately 3 million seeds several times per year. Miconia seeds are brown in color and are easily spread by birds and other animals when they eat the fruit. Seeds are also spread by humans when contaminated dirt or mud sticks to shoes, clothing, equipment, or vehicles. Some Miconia seeds can remain in the soil for 6 or more years before sprouting, which means that periodic surveys of areas with established seed banks are an essential part of controlling this species.
Pampas grass is a large bunchgrass from South America.
The leaves are narrow and have sharp, serrated edges, and the showy white to purple flower plumes are sometimes used in floral arrangements. Both species of pampas grass are considered serious pests in California and New Zealand, where they outcompete native species and create a fire hazard. Both species of pampas grass were planted as ornamentals in upcountry Maui, and C. jubata has spread to other yards, pastures, and native forests. Cortaderia jubata plants are able to produce viable seeds without pollination, and seeds are spread primarily by wind. It is considered very invasive and is on the Hawaii state noxious weed list .