Dazzling Dry Summer


What's In Bloom Virtual Tours


May - June

Trees that bloom in the intense heat of May and June are responding to the increased soil temperatures. Many of them have tropical origins. Some are native to other places where this season is especially dry. Pollinators include bees, hummingbirds, bats, and butterflies and other insects. Seeds will develop so that they can be dispersed prior to summer rains.


Cactus species -

Characteristics: delicate, brilliantly colored and often large blooms

Campus locations: Krutch Garden, Old Main, Likins Hall, Arbol de la Vida

Likins and Arbol de la Vida display a unique yellow spined barrel native to Tucson (discovered and developed by Chris Monrad and the Tucson Cactus and Succulent Society)

Cactus species

Saguaro - Carnegiea gigantea

Characteristics:Thick waxy white flowers; The Arizona State flower
Origin: Native to Sonoran Desert key species;
Campus locations: Krutch Garden; North of Old Main; East of Math

Carnegiea gigantiea

Pink bottle tree - Brachychiton x excellens

Characteristics: Pink 3" velvety flowers.
Origin: Native to Australia.
Campus locations: South of Bio Science West

Brachychiton x excellens

Golden chain tree - Cassia fistula

Characteristics: Long chains of bright yellow flowers
Origin: Native to Indian subcontinent
Campus locations: West of Nugent

Cassia fistula

Jacaranda - Jacaranda mimosifolia

Characteristics: Lush Indigo flowers
Origin: Native to South America; these particular ones from high elevation
Campus locations: South of Main Library

Jacaranda mimosifolia

Cassia leptophylla

Characteristics: Neon “knock your socks off” yellow flowers
Origin: Native to Tropical America
Campus location: East of Main Library

Senna spectabilis

Kalahari Christmas tree; Marabou thorn - Dichrostachys cinerea

Characteristics: Ornate pink/white “earring” flowers
Origin: Native to African dry lands
Campus locations: South of Graham/Greenlee Hall, East of Social Sciences

Dichrostachys cinerea

Calabash tree - Crescentia alata

Characteristics: Brown (bat pollinated) flowers emerging from trunk
Origin: Native to Mexican tropics
Campus locations: Magic Alley south of Old Chemistry; south of Main Library


Crescentia alata

Sonoran cordia - Cordia sonorae

Characteristics: White flowers that change to warm brown
Origin: Native to Mexican tropical deciduous forest
Campus locations: Magic Alley, south of Old Chemistry


Cordia sonorae

Bottle brush tree - Callistemon citrinus; Callistemon ustralis; Callistemon viminalis

Characteristics: Red pendulous flowers that resemble bottle brushes.
Origin: Native to Australia.
Campus locations: Education courtyard; NE of Physical/Atmospheric Sciences; south of Manzanita-Mojave; south of Engineering

Callistemon citrinus

Kapok tree; Floss silk tree - Ceiba acuminata

Characteristics: Pale pink 5" flowers, open at night
Origin: Native to Mexican tropical deciduous forest
Campus location: SW of Math

Ceiba acuminata

Siris tree - Albizia lebbeck

Characteristics: Pale green 2" puffballs, resembling shaving brushes
Origin: Native to Southeast Asia & Australia
Campus locations: South of Cochise

Albizia lebbeck

Monk’s pepper tree - Vitex agnus castis

Characteristics: Spikes of blue flowers
Origin: Native to Mediterranean
Campus locations: West of Old Chemistry; south of Maricopa; NW of Speech Pathology

Vitex agnus castis

Desert willow - Chilopsis linearis

Characteristics: Fluffy pink/violet flowers
Origin: Native to Sonoran Desert, especially in stream banks
Campus locations: SW Yavapai; east Harvill; SW Old Main

Chilopsis linearis

African baobab - Adansonia za

Characteristics: Chalice shaped gold flowers
Origin: Native to Madagascar; largest one in US; UA Heritage Tree
Campus location: SW of Administration

Adansonia za

Horseradish tree - Moringa oleifera

Characteristics: Chains of pale yellow flowers
Origin: Native to India & Africa; widely seen in tropics
Campus locations: North of Herring; south Vet Sci/Micro; south of Gila

Moringa oleifera

Giant milk weed - Calotropis procera

Characteristics: Clusters of velvety purple flowers
Origin: Native to India, Middle East, Africa
Campus locations: West of Science Library, South of Gould Simpson

Calotropis procera

Alamos pea tree - Brogniartia alamosana

Characteristics: Deep wine pea flowers
Origin: Native to Mexican tropics
Campus locations: West Science Library (recovering from 2011 freeze)

Brogniartia alamosana

Crape myrtle - Lagerstroemia indica

Characteristics: Profuse red, white flowers
Origin: Native to China & Japan
Campus locations: east of Nugent;

Lagerstroemia indica

Red Mexican Bird of Paradise - Caesalpinia pulcherrima

Characteristics: Profuse red/orange tropical blooms
Origin: Native to tropics
Campus locations: South of Nugent; along Campbell Avenue; along Cherry Avenue

Caesalpinia pulcherrima


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