If you live anywhere in a suburban area, you have encountered the plague of Argentine ants (Linepithema humile), those little brown irritants that crawl up your leg while reading a book outside, cover your kitchen counters with massive troop movements, wipe out native harvester ant colonies (which are the primary food of our native horned lizards), and have now been revealed as possibly one of the key predators of California native plants.
These little buggers appear do their dirty work by forming colonies near or around the base of their victim, collecting sucking insects like scales from the surface and placing them on the roots (they use these plant sucking creatures for the sweet “honeydew” fluids they excrete), and possibly spreading pathogens to the plant. How do you know if your native plant has been attacked? The lead symptom it typically death. Suddenly, the leaves start to look sick and limp. By the end of the week the leaves are drying out and beginning their journey to various shades of morbid brown.
Here at the Chaparral Institute garden we have lost a number of plants suddenly – a huge flannel bush (Fremontodendron californicum), a gorgeous white bark ceanothus (Ceanothus leucodermis), and three beautiful Catalina ironwood trees (Lyonothamnus floribundus). Fortunately, we still have one ironwood left. But around the end of August it was looking sick. By early September the leaves were brown.