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The park gets about 7 inches of rain per year by the summer monsoon and the winter rains. Regardless of the limited rainfall, plant life has adapted to escape, avoid, or endure the drought conditions. During the rainy seasons, trees and shrubs have various shades and sizes of green foliage. Stately Saguaros and other cacti absorb moisture and sport an expanded girth. Seasonal wildflowers, completing entire lifecycles during the year, form splashes of color across desert floor. When the dry season or a drought arrives, the cacti, trees and shrubs continue to live under the driest conditions. Succulent cacti survive with the help of their stored moisture and slow metabolism. Other plants shed leaves and branches to prevent moisture loss. Some shrubs may even have smaller than normal leaves or a reflective fuzzy leaf surface. Other shrubs idle as a tangle of woody stems, completely void of leaves. One must not be fooled, however, into assuming these leafless, brittle plants are dead; they are surviving in a dormant state until sufficient rainfall arrives. Likewise, wildflower seeds may lie dormant for years and not begin their short lifespan until enough rain has fallen to foster germination.
DESCRIPTIONS OF NATIVE PLANTS ALONG THE TRAIL
TRIANGLE LEAF BURSAGE (Ambrosia deltoidea) These light green sub-shrubs that lose their leaves in drought periods, act as nurse plants and are responsible for sheltering and shading young cacti that grow beneath them. During drought periods, these little shrubs are woody, leafless and appear dead.
CREOSOTE (Larrea tridentata) Often thought to be one of the oldest living plants on earth, the Creosote can live several thousand years. It is also one of the most drought-resistant shrubs and will bloom throughout the year after it rains.
CHRISTMAS CHOLLA (Opuntia leptocaulis) This sprawling cactus is often shrub-like in appearance and has slender terminal joints. The small, yellow flowers that open in Mayor June produce a stunning red fruit by winter.
FOOTHILLS PALO VERDE (Cercidium microphyllum) These green, multi-trunk trees burst into yellow bloom for two weeks during the spring and are pollinated by several types of solitary bees. The park has more Foothills Palo Verde than any other tree.
BANANA YUCCA (Yucca baccata) This Yucca blooms between April and June. Unlike the Agave, a Yucca will flower many times in its lifetime. The resulting seeds are dispersed by fruit eating animals.
DESERT IRONWOOD (Olneya tesota) Located 15 feet left of trail. This extremely slow growing tree has been estimated to live several hundred years. It sheds its leaves before a beautiful display of lavender flowers will appear in the spring.
SAGUARO (Carnegiea gigantea) The Saguaro (pronounced sa-war-o) is the signature plant of the Sonoran Desert and its flower is Arizona's state flower. Very slow growing, the Saguaro does not sprout arms until it is between 50 and 100 years old. It flowers in May. Its white blossoms open in the evening and close by the next day. A month or so later, the ripe fruit opens to show a scarlet interior, to attract birds and other animals to the seeds.
| JOJOBA (Simmondsia chinensis) (Pronounced ho-ho-bah) This evergreen shrub has leathery gray-green leaves that have a vertical orientation. The ratio of male to female plants is 4 to 1, respectively. The female plant produces a waxy nut that when processed, is used as an ingredient in cosmetics. |
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DESERT MISTLETOE (Phoradendron californicum) The clump of growth on the branches of this Palo Verde is Desert Mistletoe. These partially parasitic plants spread by producing berries that are eaten by birds. The seeds of the berries germinate after being deposited in bird scat on host's plant branches. Mistletoe growth damages the host plant by using the hosts food supply, and ultimately may kill the host.
CHUPAROSA (Justica californica) Look for the red-colored tubular-shaped flowers on this pale shrub during the winter months. The flowers are a favorite source of nectar for Hummingbirds, thus the common name, "Hummingbird Bush" is often used.
COMPASS BARREL (Ferocactus cylindraceus) These cacti have a common name "Compass Barrel" because of a tendency to lean to the southwest. Taller specimens are sometimes seen toppled over as a result of too much leaning. Pinnacle Peak Park has several specimens over 4 feet tall.
TEDDY BEAR CHOLLA (Opuntia bigelovii) Look out! The joints on this Cholla break off with ease, giving the false impression that it jumps onto people and animals passing by.
LICHEN/ MOSSES Splashes of orange, yellow and dark and light green on rocks are lichens and mosses - organisms that are slowly dissolving the rock. Mosses turn soft and vibrant green shortly after a rain. Look for lichen and mosses on rock and wood in shady locations of Pinnacle Peak Park.
| OCOTILLO (Fouquieria splendens) Often looking dead and often mistaken for cactus, this tall, slender-stemmed, semi-succulent is quick to lose leaves during dry weather, but will sprout new ones within a few days after a rain. The tubular-shaped flowers bloom in spring, regardless of rainfall amount. Hummingbirds and Carpenter Bees obtain nectar from the reddish-colored blooms. |
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RED BERRY JUNIPER (Juniperus coahuilensis) Located hillside approximately 9 feet above trail beyond the 3/4 mile marker. It is one of four known specimens in the park, all on the shadier slopes of Pinnacle Peak Mountain. Leaves are waxy and retained year-round.