Is it deer resistant?

Yes

Mexican Pricklepoppy is deer resistant.

Argemone mexicana

Deer: Rarely
Height: 3 ft 3 in (1 m)
Spread: 20 in (50 cm)
Zones: 2–12
Light: Full sun

Annual
Biennial

Mexican Pricklepoppy (Argemone mexicana)

Photo: Chachacomo · CC BY-SA 4.0

Also called Mexican Prickly Poppy, Mexican Thistle, Prickly Poppy, Thornapple

Annual Argemone

More details

Light: Full sun
Water: Low
Type: Annual, Biennial
Maintenance: High, Low
Growth: Medium
Bloom: Spring, Summer
Features: Drought tolerant, Flowering, Poisonous