Desert Wildflower Blooms

Wildflower Reports for 1999-2002

Spring 2002
March 22, 2002: Drove from Tucson through S. Calif. to central Baja last two weeks. Extremely parched except for a very nice wildflower bloom between San Felipe and Puertecitos, BC. Perennial flowers will probably be scarce here this year because of the extremely dry winter. Even the cacti may perform poorly - they're shriveled up and look like June already.

Early February 2002: There has still been almost no rain in southern Arizona (since last August), so annual wildflowers will be almost nonexistent this spring. Large areas of the newly-created Ironwood Forest National Monument (just west of Tucson and south of Picacho Peak State Park) is actually green with tiny seedlings from a wayward storm. But they have not grown for several weeks and will soon die unless rescued by another rain.

Perennial plants may still bloom if there is a rain soon. Stay tuned.

SPRING 2001
Wildflower update early March: February was very dry and cooler than normal in Tucson and most of southern Arizona. The annual wildflowers here continue to bloom because the cold weather has slowed soil drying, but they are near their end unless a good rain comes very soon. The first week in March is probabaly your last chance to see a good show.

Brittlebush is well past peak but still colorful for another week or so. Most perennials have not begun to flower yet, but delphinium and mariposa lilies have sprouted and should bloom well this spring. Some early ocotillos will be in bloom by mid March in Arizona Upland and are probably already in bloom in the lower desert.

February 15, 2001: The annual wildflowers are at their peak bloom in many places in the desert of southern Arizona, and the sparse rainfall means the show will probably end soon. If you want to see it, don't wait. Here's what we know:

Tucson Mountains: This is the best show of annual wildflowers in at least 20 years. Whole hillsides are covered with wildflowers. Most of the color is from poppies, lupines, bladderpod mustard, and desert chicory. Many other species are also in bloom, including anemone, desert hyacinth (Dichelostemma), phacelia (2 species), and silver bells. Brittlebush is fading, and the annuals are wilting on the sunnier slopes.

Organ Pipe Cactus National Monument: Disappointing this year; mostly non-showy species so far. Brittlebush mostly failed to bloom, indicating a dry year.

Ironwood Forest National Monument (newly-created, not on maps): There are several fields of poppies and lupines on the roads that loop around the Silverbell, Waterman, and Ragged Top mountains an hour west of Tucson.

Gran Desierto and Pinacate (Mexico): No word on the Pinacate. The dunes around the Sierra del Rosario are a mass of sand verbena and dune evening primrose.

Picacho Peak State Park: It's famous poppies and other flowers are in full bloom.

Catalina State Park: The Sutherland Trail has a good bloom in progress. It's cooler here, so it should last longer than in some other locations?

Tohono O'odham Reservation: Highway 86 west of Tucson has large stands of poppies with some owl clover and lupines, especially near the Kitt Peak turnoff.

Arivaca-Ruby road loop (west of Interstate 19 north of Nogales): Higher elevation area. Bladderpod mustard is blooming massively right now. This is an early species, so there is hope of an even better display later.

JANUARY 12, 2001: Mid January storms dropped significant rain over much of southern Arizona. Hope of good displays is therefore still alive. Annual and herbaceous perennial wildflowers in the low and intermediate deserts will probably peak in February, since many are already in bloom now. How long it lasts depends on later rains.

JANUARY 2, 2001
Several storms crossed eastern Arizona between late September and early November 2000. The rain totaled about 6 inches in Tucson and triggered mass germination of annual wildflowers. But it has been nearly rainless from then to the end of the year. This report is based mostly on a late December survey of the loop from Tucson to L.A. via Interstate10 and back from San Diego via I-8. It therefore covers the southern deserts in the U.S.; I have no information about more northern localities; Sonora has reportedly been wet and holds a promise of flowers.

The fall storms missed southwestern Arizona and southern California; this area is parched. Barring very unusual weather, it is too late for rains to trigger a significant bloom in the west.

BEYOND THE DESERT

The center of the fall storm tracks passed over southeastern Arizona just to the east of the Sonoran Desert. Coronado National Memorial in the Huachuca Mountains received 12 inches of rain in October alone. The ample rainfall and cooler temperatures in the higher elevations of the desert grassland and oak woodlands slows soil drying, so there is a substantial possibility of a good wildflower display if at least some more rain falls before spring.

Tucson Rainfall in inches:

SPRING 2000
(Updated March 2000) The Southwest is under the influence of a La Niña event for the second consecutive year. In such years winter rainfall in southern Arizona is typically only half of the average and the last two winters have had even less. Most of the Sonoran Desert received much less than the required inch of rain before mid December. The rainfall table below shows the past few years and the average rainfall for the Desert Museum (which is wetter than the official Tucson weather station at the airport). [Learn which plants bloom during the year and how to predict when they do.]

Saguaros and trees usually flower every year. But since this has been the driest winter in many years, we won't promise the trees until we see the flowers opening.

The good news is that flowers are blooming in irrigated gardens at the Desert Museum and botanical gardens. This year such places are definitely your best bet. There will also be scattered flowers to be found in sheltered canyons wherever extra rain has fallen.

BUT SURPRISE! Almost the entire 450-mile stretch of Interstate 10 between Tucson, Arizona and Palm Springs, California is parched and brown this winter. But an isolated storm brought rain to a tiny patch of sand dunes west of Blythe, California. These images were taken on December 27, 1999 at the Wiley's Well exit. The sand verbena (lavender) were past their peak and drying out, but the evening-primroses (white) and desert sunflowers (yellow) were just beginning to flower. There is a similar patch of wildflowers in the middle of the otherwise shriveled Vizcaino desert in Baja California.

Summer 1999
La Niña events do not suppress the summer monsoon season, and often stimulate it. The summer of 1999 experienced the longest monsoon season in Tucson history, about 90 days. (There are differing methods of measuring the onset and end of the monsoon; see the Tucson NWS site for details.) It was also one of the wettest with over 11 inches - nearly twice the average for June through September. Even more important than the total from a biological perspective was the fact that it rained nearly every other day in July and August, so the soil was continuously moist. This produced tremendous vegetative growth of perennial plants, and stimulated many plants to flower better than usual.

Spring 1999
The spring blooming season was poor, but not quite as bad as expected. The winter of 1998-99 was the driest in 30 years until the drought was moderated by a soaking rain (more than an inch) on April 1, followed by a snow on Easter Sunday.

• • There were almost no annuals or herbaceous perennials due to the poor fall and winter rains.

  • Most shrubs and subshrubs such as brittlebush, fairy duster, and penstemons didn't even leaf out let alone flower. (But the April Fool's day rain caused the fairy duster to burst into full bloom at the end of the month; it usually peaks in February. Creosote bushes also leafed out and flowered in May.)

  • Ocotillo flowered superbly; this species has never failed in the 30 years I've been observing it (fortunately for the migrating hummingbirds). This spring's bloom lasted longer than the usual four weeks. Plants began three weeks early because of the warm winter, starting in the second week in March in Tucson. Some plants were still in bloom the second week in May, probably because of the cooler late spring and the unseasonal late rains

  • Blue and foothill palo verdes flowered poorly on the whole. Blues, which grow in washes and benefit from the drainage, flowered normally in some areas but failed in others. Foothill palo verdes flowered only in the wetter locations on roadsides and deeper soils; most trees on rocky hillsides failed to bloom at all.

  • Desert ironwood trees flowered profusely in mid May. We don't know what triggers this species.

  • The smaller cacti were largely a flop despite their water-storing habit. Chollas flowered almost normally, but most prickly pear plants flowered sparsely or not at all. Most hedgehog cacti did not bloom.

  • Saguaros flowered well as usual last May and June. They have huge stores of water and one dry winter does not affect them noticeably.