The Desert Botanical Garden’s Wildflower Info Site returns to provide up-to-date reports on desert wildflower blooms in central and southern Arizona. The site, a collaborative effort by 21 parks and gardens, is live during the months of March and April at www.dbg.org/wildflowers.
Wildflowers blooms are unpredictable. There is no way to accurately predict from year to year whether or not spectacular blooms will occur. The Wildflower Info site takes the guess work out of finding wildflowers in Arizona. Based on the lack of rainfall this year, scientists and horticulturalists at the Garden are predicting a minimal wildflower bloom in nature for spring 2013.
In the Phoenix Metro Area, Wildflower Info Site participating parks and gardens include: Desert Botanical Garden, South Mountain Park, Usery Mountain Park, White Tank Mountain Regional Park, Estrella Mountain Regional Park, Cave Creek Recreation Area, Spur Cross Ranch Conservation Area, and Thunderbird Conservation Park.
In areas near Phoenix, participating parks and gardens include: Agua Fria National Monument, Tonto National Monument, Boyce Thompson Arboretum, and San Tan Mountain Regional Park.
In western Arizona, participating parks and gardens include: Kofa National Wildlife Refuge and BLM – Colorado River District (Lake Havasu).
In southern Arizona, participating parks and gardens include: Picacho Peak State Park, Tucson Botanical Gardens, Saguaro National Park East District, Saguaro National Park West District, Tohono Chul Park, Organ Pipe Cactus National Monument and Arizona Sonora Desert Musuem.
We’ve Got Blooms at the Garden!
The Desert Botanical Garden’s two acre Harriet K. Maxwell Desert Wildflower Trail opened in 2001 and is dedicated to the beauty and appreciation of desert wildflowers and their pollinators. The Garden’s horticulture team spent early fall prepping and seeding the trail and late fall and winter irrigating the plantings, and they expect an abundant wildflower bloom during March and April including Penstemon, Desert Lupine, and Mexican and California Poppies.
Wildflower Bloom Background
The two most important conditions needed for annual wildflowers is rainfall and an optimal soil temperature. Mass or landscape-wide blooms coincide with fall-winter rains that are wetter and begin earlier than usual. Rainfall most often has to be at least one inch to initiate germination of most annual wildflowers. In addition, it has to rain one inch per month through March. Germination of spring-blooming annuals occurs when soil temperatures are cooler in the late-fall and winter months. Spectacular flowering is a rare event and may occur every ten years. Because rainfall varies from location to location and wildflowers can germinate and grow on less than one inch per month, localized blooms are common every three to four years.
The flowering event for spring-blooming annual wildflowers can be seen from late February through May. For the Phoenix area peak flowering usually occurs around mid-to late March. Some common spring-blooming wildflowers can include Mexican Gold Poppy (Eschscholzia californica ssp. mexicana), Lupine (Lupinus sp.), Owl-clover (Castilleja exserta), Bluebell (Phacelia campanularia), and Chia (Salvia columbariae).
Because the Sonoran Desert has a bimodal rainfall system (fall-winter & summer rains) there is also a host of summer-blooming annuals. Summer annuals germinate upon warmer soil temperatures and with summer rainfall. These summer annuals grow rapidly and bloom within the same season from late summer through early fall. Some common summer-blooming wildflowers include Arizona Poppy (Kallestroemia grandiflora), Devil’s Claw (Proboscidea parviflora), and Chinchweed (Pectis papposa).