Seed to Sentinel

Seed to Sentinel. Saguaro National Park. Standing like desert sentinels, mature saguaros start life as tiny black seeds. These seeds usually germinate under nurse plants but only a few survive to become mature saguaros., Look for young saguaros growing low to the ground. Those that are about the size of your thumb may be several years old. In contrast, tall saguaros with many branching arms can be 175 or 200 years of age. Known as “ancient giants,” these cacti eventually die, decay, and drop woody, internal skeletons to the ground., During a walk along any park trail you can discover saguaros in their various stages of life and death., Reproduction , Saguaro reproduction begins during the hottest and driest weeks of the year, late spring and early summer. This is when white-winged doves, bees, and bats travel to blossoms, transporting pollen, fertilizing as they go. Saguaro fruit usually ripens in late June. Each fruit contains as many as 2,000 seeds. Coyotes, javelinas, foxes, rodents, and many birds feed on these seeds and the fruit’s lush, red pulp., (Key to numbers) , 1. Seedlings-The newborn saguaro is most vulnerable during the first few years of life. Birds eat seeds and seedlings. People step on them. Thousands of young plants can die because of intense sun or heavy rain. , 2. Establishment-New saguaros survive best under shade or “nurse plants” such as palo verdes and mesquites. , 3. Youth-Saguaros begin flowering after they grow about eight feet tall. , 4. Maturity-When saguaros reach about 75 years of age, they might begin sprouting branches or “arms.” , 5. Old Age-The oldest saguaros may weigh more than 7 tons and grow taller than a four-story building. , 6. Decline-Severe freezing, wind, lighting, vandalism, and disease are factors that result in saguaro damage or death. Saguaros seldom live more than 200 years.