Pronounciation: FEE-nix dac-ti-LI-fer-a

Hardiness zones
Sunset 11, 12-24
USDA 9-11 (arid and semi arid regions best)

Landscape Use: Large parks and commercial areas usually around entry ways, street tree, vertical accent, strong oasis effect, desert fruit gardens.

Form & Character: Strongly upright and vertical, visually dominant, dangerous, gray, oasis.

Growth Habit: Evergreen, perennial monocot, basally clumping, moderate growth rate to 100 feet (often less), rarely branched, trunk slender and able to bend.

Foliage/Texture: Feather palm with gray to grayish glaucous sometimes bluish fronds to 15-feet long, pinnae in pairs at somewhat acute angle from rachis, needle-sharp at base of frond, fronds persistent and must be pruned (often creatively) leaving diamond shaped frond-petiole scars that are slightly wider than than high; coarse texture.

Flowers & Fruits: Date palms are dioecious (male and female flowers on separate plants), flowering occurs in late spring. Natural pollinators are bees, though normally in urban horticultural and agricultural locations pollination of female flowers with male pollen is done manually by hand (sometimes involving use of heavy equipment and machinery for large, tall mature trees), or recently 'artificially' from above the tree crown via the use of artificial intelligence (AI) and aerial drones. Fruits when immature are green, begin to ripen in September, color ranges from orange and yellow to red, fruit borne in clusters, oblong containing a pointed seed, fruits mature (fully ripen) in October to a darkened orange to reddish brown, have a high sugar content when ripe.

A fertility note: In commercial date orchids there is one male tree per 40 to 100 female trees necessary for fruit production, a mature female tree can yield 100 to 200 pounds of fruit per year.

Seasonal Color: Orange fruit clusters in fall that must be bagged to protect the fruit from the hungry birds who love to eat date fruits more than people do.

Temperature: Apical meristems can be killed at 20^oF, otherwise the plant itself can survive 4^o to 10^oF.

Light: Full sun

Soil: Tolerant

Watering: Deep infrequent irrigations best using a flood bubbler system into a bermed basin around the base of the palm.

Pruning: Remove 'skirt' of old fronds with pruning saw. The wearing of arm, hand and eye protective gear when pruning off fronds and old fruit stalks is IMPERATIVE because of rigid and sharp frond pinnae.

Propagation: Division of offsets with wedge or chisel, then root in a large pot with occasional mist, tissue culture.

Disease and Pests: Fusarium wilt (fungal disease) can kill young seedlings or mature trees, insect borer larvae can damage trunks or kill apical meristems.

Additional comments: Date palm has a long ethnobotanical history. Wear protective clothing and goggles when pruning leaving ten fronds per fruit cluster for optimum fruit quality.

Date palms are easily transplantable during the time of year of active root growth (warm season). However, recent research has shown that the common industry practice of 'tying' the fronds into a tight bundle to prevent 'desiccation' of the apical meristem during transplanting actually increases the chances of transplant failure because the stomates on the undersides of the fronds are more exposed to drying air causing greater water loss. Rain at date harvest time in late summer and early fall causes fruit rot.

Some popular or notable date palm cultivars that are locally found include:

• 'Black Sphinx'
  
• 'Desert Noor'
  
• 'Honey'
  
• 'Halaway'
  
• 'Khadrawy'
  
• 'Male'
  
• 'Medajool' (originally from Morocco, but a soil disease eradicated all of them in their native range leaving only those that were earlier exported to southern California and Arizona.)
  
• 'Zahidi'
  

A special note: Arizona State University maintains one of the world's largest and diverse date palm collections.