Arizonensis --> Sonoran Desert Naturalist --> Sonoran Desert Places --> South Mountain
Desert Wild Flower Reports ¦ Field Trip Reports ¦ Birds ¦ Cacti ¦ Shrubs and Trees ¦ Map
The city of Phoenix reckons this to be one of the largest city parks in the world! The miles and miles of trails lead through some pretty spectacular and surprisingly rich Sonoran Desert habitats and yet is easily reached by driving a few miles south on Central Avenue from the hustle and bustle of downtown Phoenix.
Urban sprawl has crept way to the south of the South Mountains -
the fight will be to keep developers and Ahwatukee residents from demanding a
road through this preserve. Recently, some residents of this area have filed
complaints with the Arizona Game and Fish department about javelina (peccary)
coming into their yards to devour ornamentals and to dig up lawns. Maybe these
complainers should just move back away from the edge of the desert. Only when
you have a view to the southwest onto the Gila River Indian Reservation do you
not see a sea of rooftops and urban golf courses and their profligate use of
A great reference on the flora of South Mountain is: Flora of the South Mountains of South-central Arizona (Daniel & Butterwick), Desert Plants (v. 10, # 3, p. 99-119).
Adapted from Phoenix Parks & Rec. Map.
A couple of weeks' worth of pretty good monsoon rains prompted me to venture out at dawn to see what had greened up. I found that a brush fire has scorched a large section north of the San Juan Road and behind the ranger building. Many saguaros and barrel cactus have been destroyed. The abundant dried vegetation from a wet spring was certainly a factor, but so were the abundance of exotic invasives and the exclusion of key wildlife species such as javelina and deer.
Some interesting observations on the day were many saguaros with fruit just ripening - nearly a month and a half later than the principal fruiting time and another saguaro with a solitary blossom open. There were plenty of butterflies on the wing and I watched Orange Sulfurs (Colias eurytheme) laying eggs on fresh ironwood growth. A raven seemed out of place - normally they don't move onto the desert until autumn. Possibly some of the recent range fires have displaced ravens from their higher elevation haunts.
We hiked the Bajada Trail which parallels San Juan Road on the
west side of the park. It was sprinkling and threatening to rain much harder as
temperatures hovered around 15°C. Eventually we were pummeled by rain mixed
with ice pellets. Gordon's Bladderpod were open everywhere covering the
landscape in mustard-yellow. Hundreds of California Gold Poppies on the other
hand were still unfurled awaiting the return of golden sunshine. Dozens of
other species were in bloom also, filling the air with an over powering
sweetness. See list below under Desert Wildflower Report
Amazing show of wildflowers!! The rains came very late after a
record breaking-drought. There was just one big rain of some 75 mm during the
first week of March. Most spectacular wildflowers are those of perennial
species, especially Creosote Bush. But even a few Poppies are blooming!!
Strictly drought conditions. A very few Creosote Bushes and Brittlebush in bloom mostly near roadside culverts. Even hiking into some steep, north-facing canyons I found nary a thing. However, when I got down real close to the ground and looked carefully I found diminutive blooms of Orange Fiddleneck and White Popcorn Flower. The fiddleneck was barely one cm tall (in 1998 these plants reached heights well over one meter) and had just two tiny orange flowers. These plants took a chance and sprouted with the wet weather at the start of February. Now they will be lucky if they produce even one replacement seed that will survive until the next bout of wet weather.
Prominent knolls and hilltops throughout the Sonoran Desert
often host a collection of flying insects milling about the summit.
Entomologists have discovered that most of these are males. Through
evolutionary time these places have come to be prearranged meeting places for
males and females. Many desert insects are scarce and widely spaced which makes
this prearranged meeting place all the more efficient.
At South Mountain Park I found males of Tarantula Hawk (large black and red-winged spider hunting wasp) patrolling around hilltop prominents, then flying off to check nearby hilltops.
Male Hover Flies (black and yellow beelike markings, about 1 cm) hover like miniature helicopters just 15 cm above the ground. Several male hover flies share the hilltop and make sure others don't infringe on the areas they stake out. Sarcophagid Flies (look like robust versions of standard House Flies) perch on the ground and make frequent forays to chase away any neighboring male that has moved too close to a preferred spot.
A male Sara Orangetip Butterfly (white with a conspicuous orange
patch in the corner of the front wing, wing span about 4 cm) plays the game
like the Spider Wasp, quickly sailing off towards an adjacent hill. Once a
newly hatched female of any of these insect species makes its way to the
hilltop it does not take long for her to be met by an eager male. The pair
quickly fly off together so the naturalist may not get a chance to observe this
occurrence. But, hilltops are a grand place to stop and rest and maybe eat you
lunch. You will be joined there by a fascinating array of creatures that are
fun to watch.
It has been a long drought period. Not even 4 inches of rain has fallen so far this year as measured at the airport located 10 miles away. Certainly more precipitation has fallen on South Mountain with the added elevation, but not much. The Ocotillos are a good guide to past rainfall. All the ocotillos are completely bare of leaves, resting dormant until the rains come again. A few sprinkles of rain have fallen the past week or so, just enough to encourage the Selaginela and rock ferns to show hints of life. The ferns are mostly still brown, cowering in the shade of huge boulders, ready to spring forth when a good rain arrives. Any day now, or maybe in a couple of weeks, or maybe not for a long time. Desert survivors have to be ready for rain and drought at the same time. The most visible signs of green are the trunks and branches of Foothill Palo Verdes. Rivaling the few green trees are the rocks themselves. The ancient schist and gneiss are superb substrates for bright green and yellow lichens. There are lots of colors here.
The Hidden Valley Trail provides access to the most pristine area of the park. The trail head can be reached from the very end of the road up the mountain, past all the TV towers. Or else one can hike up Pima Canyon from outside the east end of the park. Finding wild flowers after a long drought is a rewarding challenge. A very few can still be found in bloom, mostly along north facing slopes that get shaded for part of the day. Cream colored blooms are on the Indian Tobacco. The leaves give off that lovely tobacco aroma, that even most nonsmokers can appreciate. These herbaceous plant rarely grow taller than two feet.
I found a couple of rogue Desert Lavender bushes in bloom. Many Honey Bees were there competing for some nectar at the purple blossoms. This relative of sage has a sweet pungent odor to its foliage and grows to a large sized shrub, 2 to 4 feet. And a few pale lavender flowers of Wire Lettuce are scattered here and there. The 1/3 inch wide flowers are 4 to 6 pointed. The plant grows up between other shrubs and the thin stems often rest upon them. Little else than the flower structure and the milky sap from broken stems suggests its kinship to cultivated lettuce.
Just a quarter mile from the parking area are some of the Elephant Trees, but these ones are only shrub size. Bigger specimens can be seen a mile or so further on. The verdant foliage of the Elephant Trees seems out of place here. South Mountain Park is the furthest north that this species grows in Arizona.
The most common bird in the park is the Rock Wren. Its high pitched trill emanates from piles of boulders where the pale gray bird often perches at the top. The Gila Woodpecker and the Gilded Flicker call noisily from areas of tall Saguaros.
A half mile down the Hidden Valley trail will take you through a small patch of Four-winged Saltbush. Above the drab olive green foliage are dense clusters of glistening golden brown seeds. These attractive plants have been used sparingly in landscapes. Much of the recent growth on Mormon Tea shrubs is being aborted with the greens first turning a rich shade of reddish brown. Desert plants often must shed excess twigs and branches when water becomes too scarce.
(more frequent towards top of list)
This trail begins from the lower picnic ground areas just beyond the entrance on Central. It is a short mile or about 1½km up to the juncture with the Summit Road. The GPS Coord. for trailhead are: 33.34069 N 112.07613 where the elevation is 487 m. At the road juncture the elevation 615 m for a climb of 128 meters. Cholla and prickly pear cactus are notably scarce along this trail. The list here has the more common species listed first and was created based on a field trip on 27 Jan. 2008.
|Common Name||Scientific name||Color||Jan||Feb||Mar||Apr||May||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Gordon's Bladderpod||Lesquerella gordonii||Jun||Jul||Aug||Sep||Oct||Nov|
|Thelypody Mustard||Caulanthus lasiophyllus||/||Jun||Jul||Aug||Sep||Oct||Nov|
|Sand Peppergrass||Lepidium lasiocarpum||Jun||Jul||Aug||Sep||Oct||Nov|
|Arch-nutted Comb Bur||Pectocarya recurvata||Jun||Jul||Aug||Sep||Oct|
|Texas Filaree||Erodium texanum||Jun||Jul||Aug||Sep||Oct||Nov|
|Bearded Cryptantha||Cryptantha barbigera||Jul||Aug||Sep||Oct||Nov|
|Orange Fiddleneck||Amsinckia intermedia||Jul||Aug||Sep||Oct||Nov|
|California Poppy||Eschscholzia californica||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Torrey Eucrypta||Eucrypta chrysanthemifolia||Jul||Aug||Sep||Oct||Nov||Open|
|Lace Pod||Thysanocarpus curvipes||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Coulter Lupine||Lupinus sparsiflorus||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|London Rocket (weed)||Sisymbrium irio||Jun||Jul||Aug||Sep||Oct||Nov|
|Mustard (weed)||Brassica tournefortii||Jun||Jul||Aug||Sep||Oct||Nov|
|Desert Rock Pea||Lotus rigidus||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Brittle Bush||Encelia farinosa|
|Golden Eye||Viguiera deloidea|
|Desert Globe Mallow||Sphaeralcea ambigua|
|Bigelow Four O'Clock||Mirabilis bigelovii|
|Desert Trummpet||Eriogonum inflatum|
|Desert Poinsettia||Euphorbia eriantha||/|
|Shrubby Bedstraw||Galium stellatum|
|Creosote Bush||Larrea tridentata|
|White Ratany||Krameria grayi|
|Sweet Bush||Bebbia juncea|
|Foetid Marigold||Dyssodia porophylloides|
|Desert Marigold||Baileya radiata|
|Creosote Bush||Larrea tridentata|
|Triangle-leaf Bursage||Ambrosia deltoidea|
|White Bursage||Ambrosia dumosa|
|Canyon Ragweed||Ambrosia ambrosioides|
|Desert Lavender||Hyptis emoryi|
|Englemann Hedgehog||Echinocereus engelmannii|
|Lance-leaf Ditaxis||Argythamnia lanceolata|
|Elephant Tree||Bursera microphylla|
|Desert Tobacco||Nicotianna trigonophylla|
|Trailing Four O'Clock||Alionia incarnata|
|Angel Trumpet||Acleisanthes longiflora|
|Desert Senna||Senna covesii|
|Janusia Vine||Janusia gracilis|
Desert Field Guide
Sonoran Desert Places
Sonoran Desert Naturalist Home Page