Gardening can be very costly so its always best to first learn about what native plants survive in the Sonoran Desert before you start landscaping your yard. According to the Arizona-Sonora Desert Museum, the Sonoran Desert as currently defined covers approximately 100,000 square miles (260,000 sq. km.) and includes most of the southern half of Arizona, southeastern California, most of the Baja California peninsula, the islands of the Gulf of California, and much of the state of Sonora, Mexico. Santa Cruz County is situated in the Arizona Upland subdivision that consists of the northeastern section, mostly in south-central Arizona and northern Sonora, it is considered the highest and coldest subdivision of the Sonoran Desert. The terrain contains numerous mountain ranges, and the valleys are narrow. Arizona Upland has five seasons, which, though more subtle than the traditional temperate four, are distinct if one learns what to look for:
Spring
From early to late February through April, mild temperatures; little rain; often windy; main flowering season for annuals, shrubs and trees; winter annuals may bloom in February in warm, wet years.
Foresummer Drought
May & June has high temperatures; very low humidity; no rain in most years; May is very warm and often windy; June is hot and usually calm. There is little biological activity except for the flowering and fruiting of saguaro, foothill palo verdes and desert ironwood trees. Nearly every living thing is in basic survival mode until the rains arrive.
Summer Monsoon
Early July to mid-September it traditionally begins with the most dramatic weather event of the region - the often abrupt arrival of the summer rains. A tropical air mass adds humidity and moderates June's extreme temperatures; frequent thunderstorms; main growing season for many of the larger shrubs and trees. (Monsoon is an Arabic word for a wind that changes directions seasonally. Be aware that it does not refer to rain or storms in any way. The word is often misused, even by some weather forecasters.)
Autumn
October & November has warm temperatures; low humidity; little rain; few species in flower, but beginning of growing season for winter annuals in the rare years with enough rain. Autumn and late summer occasionally receive heavy rains from the remains of Pacific hurricanes (tropical storms)
Winter
December, January & February, is mostly sunny, mild days, with intermittent storms with wind, rain, and cool to cold temperatures; February often warm and dry, more spring-like.
Although Santa Cruz is the smallest county for the state of Arizona. Its eco systems and unique habitat is very diverse. The wetlands can be found in Nogales as you enter the Meadow Hills Estate subdivision. The riparian system evolving from the Santa Cruz River flows between Nogales, Rio Rico, and Tubac up the I-19 corridor. While the grasslands are found in Sonoita and Elgin Arizona.
