Arizonensis --> Sonoran Desert Naturalist --> Sonoran Desert Places --> North Mountain, Phoenix
North Mountain, one of the larger units of the Phoenix
Mountains Preserve, is bounded on the north by Thunderbird Rd., on the east by
7th Street, on the south by Peoria, and on the west by 19th Ave. North Mountain
(elev. 641 m, photo at right) is on the east and Shaw Butte (655 m) above) is
located to the northwest. Both summits are crowded with radio towers.
The North Mountain Recreation Area, with access just north of Peoria Avenue off of 7th Street, has plenty of picnic ramadas and a trail that is very popular, especially for people seeking a good workout hike. This trail is much easier and also less heavily visited than either Camelback Mountain or Squaw Peak. About 2/3 of the trail follows a black-topped road to the towers at the summit. Parking is rarely a problem even on a pleasant Sunday in spring time!
Alternately, access to this area can be made from the south via Mountain View Park about 2 miles north of Dunlap on 7th Avenue. Yet another trailhead is provided on 7th Street just south of Thunderbird.
The Geology is varied. North Mountain itself is composed mostly of ancient metamorphic rock dating to the Pre-Cambrian Period. Gneiss (alternating light and dark bands) and schist (highly compressed and layered) predominate. Shaw Butte is similar, but has a bilayered cap of much younger Quaternary or Tertiary volcanic ash and basaltic lava. The huge time gap between the layers as well as the isolation of the lava flow give stark testimony to the power of erosion operating over hundreds of millions of years.
North of Mountain View Park there is a large earthen dam that protects nearby homes by lowering the risk of flooding. A thick layer of fine soil has collected behind that traps a lot of moisture; plants with deep root systems such as mesquite and blue palo verde grow there. There are salt bush, desert lavender, gray thorn, mesquites and blue palo verdes growing behind the dam.
Trail from North Seventh Street entrance: A large parking area and trailhead is provided on Seventh Street south of Thunderbird for access to trail No. 100. The trail passes beneath Seventh Street (underpass) from the preserve unit to the east. After a brief westward route, the trail then turns south through the valley that separates North Mountain from Shaw Butte. Within sight of the parking area is a small water catchment constructed with Heritage Fund support for the purpose of "habitat improvement." There are a few small Fremont cottonwoods and a sparse planting of mesquite. A barrier fence and sign ask hikers to keep out or the revegetated area. The cottonwoods turn bright yellow by late fall. About a half kilometer on trail No. 100 brings you to Trail No. 106. Turning west on this spur will bring you to an earthen dam that helps protect the housing development at Central Avenue. There are a lot of Blue Palo Verde growing on the dam and behind it. Many people prefer the flat land hiking, however, if one chooses there are connections that can be taken to ascend either summit.
The west slope of North Mountain is sparsely vegetated; the dark green shrubs at center are Creosote Bush -- Larrea tridentata.
Area map adapted from Phoenix Parks & Rec. Map. Easiest access points are from 7th Ave or 7th Street north of Dunlap. Or 7th Street South of Thunderbird.
Field Trip Reports
July 27, 2003
I discovered today why so many Cactus Wrens and Rock Wrens gather near the summit! Bright lights for security illuminate the communications tower and equipment. This draws in moths and other insects: at daybreak the wrens pick the resting insects from fences, walls and rocky surfaces.
Sept. 24, 2000
Trail from North Mountain Recreation Area to Summit. In the first canyon from the trailhead a hunting coyote caught the attention of a Rock Squirrel which kept up a continuous, very loud barking. Basically it was telling the coyote it had been seen and should not bother trying to stalk. Birds and other squirrels heard the alarm as well and kept a wary eye.
Jan. 3, 1998
Trail from North Mountain Recreation Area to Summit. Barely up the trail from the parking area there is a lone saguaro cactus that has suffered repeated pummeling with rocks. It is badly scarred with blackened injuries any of which could have resulted in a fatal systemic infection. At the very least the plant has suffered a reduction in photosynthetic ability and has been transformed into an unsightly giant. Maybe the parks department should set up a remotely activated camera to snap a picture of culprits!
UPDATE: In Sept. of 2003 as I was hiking up this trail I caught the very distinctive scent of a saguaro in death - yeasts and bacteria breaking down the flesh. The pummeled cactus had fallen and the richness of this desert preserve dropped accordingly.
In general order of Abundance:
Anna's Hummingbird (Calypte anna) females quarreling over a sip of saguaro juice. Photo © by Mike Plagens
In general order of Abundance:
In order of Abundance:
Harris' Antelope Squirrel
In general order of Abundance:
In general order of abundance:
In the list above one normally common Sonoran Desert plant is missing and I am not sure why. The missing plant is White Ratany (Krameria grayi). It is normally a small shrub with weak stems that have a purplish-brown cast. The deep maroon flowers and prickly fruit are distinctive. If you find one in any of the Phoenix Mountains Preserve units I would be very interested in knowing about it. Send an e-mail for more information: firstname.lastname@example.org
The fruits of Janusia Vine appear like small maple seeds. Three seeds each with a papery wing are joined at base.
North Mountain is a part of the Phoenix Mountains Preserve.
Brief rain in January was followed by more than a month of rain-free days. Now the first
week of March follows a week of heavy rains. Those seedlings that survived since the January
period are now blooming, but mostly on small plants. More will soon germinate, but the higher
temperatures of spring will arrive soon. The wildflowers that germinate now will grow and
flower quickly, and so will also be smaller than usual. But there will be plenty of flowers to
find and enjoy!
The chart below records the blooming months for wildflowers and flowering shrubs at North Mountain and Shaw Butte.
Month Name Only : no flowers. no live plants.
: usually no or very few blooms open
: a few scattered blooms likely to be seen
: quite a few blooms likely to be seen, depending on past rainfall
: abundant blooms dependent on favorable rainfall
|Common Name||Scientific name||Color||Jan||Feb||Mar||Apr||May||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Hairy Bowlesia -- Bowlesia incana||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Triangle-leaf Bursage -- Ambrosia deltoidea|
|Sweet Bush -- Bebbia juncea||/|
|Brittlebush -- Encelia farinosa|
|Sow Thistle -- Sonchus oleraceus|
|Desert Straw;Wire Lettuce -- Stephanomeria pauciflora|
|Goldeneye -- Viguiera deltoidea|
|Orange Fiddleneck -- Amsinckia intermedia||Jul||Aug||Sep||Oct||Nov|
|Narrow-leaf Popcorn Flower -- Cryptantha angustifolia||Jun||Jul||Aug||Sep||Oct||Nov|
|Arch-nutted Comb Bur -- Pectocarya recurvata||Jun||Jul||Aug||Sep||Oct|
|Sahara Mustard;Asian Mustard -- Brassica tournifortii||Jun||Jul||Aug||Sep||Oct||Nov|
|Peppergrass -- Lepidium lasiocarpum||/||Jun||Jul||Aug||Sep||Oct||Nov|
|London Rocket -- Sisymbrium irio||Jun||Jul||Aug||Sep||Oct||Nov|
|Compass Barrel;California Barrel -- Ferocactus cylindraceus|
|Saguaro Cactus -- Carnegiea gigantea|
|Lance-leaf Ditaxis -- Argythamnia lanceolata||/|
|Common Ditaxis||Argythamnia neomexicana||/||Jan||Jun||Jul||Aug||Sep|
|Small-seed Sandmat -- Chamaesyce polycarpa|
|Foothills Palo Verde; Yellow Palo Verde -- Parkinsonia microphylla|
|Ocotillo;Coachwhip -- Fouquieria splendens|
|Red-stemmed Filaree||Erodium cicutarium||Jul||Aug||Sep||Oct|
|Notch-leaved Phacelia -- Phacelia crenulata||Jul||Aug||Sep||Oct||Nov||Dec|
|Desert Lavender -- Hyptis emoryi|
|Desert Globe Mallow -- Sphaeralcia ambigua|
|Scarlet Spiderling -- Boerhavia coccinea||Jan||Feb|
|Indianwheat; Woolly Plantain -- Plantago ovata||Jun||Jul||Aug||Sep||Oct||Nov|
|Yellowthroat Gilia -- Gilia flavocincta||Jan||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Anderson Thornbush;Wolfberry -- Lycium andersonii||/|
|Tamarisk;Salt Cedar -- Tamarix pentandra|
|Pellitory -- Perietaria hespera||May||Jun||Jul||Aug||Sep||Oct||Nov|
|Desert Mistletoe -- Phoradendron californicum|
|Creosote Bush -- Larrea tridentata|
|Blue Dicks -- Dichelostemma capitatum||May||Jun||Jul||Aug||Sep||Oct||Nov|
|Six-weeks Three-awn||Aristida adscencionis||May||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
|Purple Three-awn -- Aristida purpurea||Nov||Dec|
|Foxtail Barley -- Hordeum jubatum||Jun||Jul||Aug||Sep||Oct||Nov|
|Mediterranean Grass -- Schismus barbatus||Jun||Jul||Aug||Sep||Oct||Nov|
|Common Name||Scientific name||Flower||Jan||Feb||Mar||Apr||May||Jun||Jul||Aug||Sep||Oct||Nov||Dec|
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