King palm overview
The smooth, fast Australian king palm. USDA 10a to 11, a green crownshaft, and less cold tolerant than a queen.
Region of origin
Northeastern Queensland, Australia
Native countries
Historical discovery
Ferdinand von Mueller named it for Princess Alexandra. Wendland and Drude placed it in Archontophoenix in 1875.
Names
Common names
King palm, Alexandra palm, Northern bangalow palm
Synonyms
- Ptychosperma alexandrae F.Muell.
Cold hardiness
Survives about 28°F / -2°C. Outdoor range USDA 10a–11b. Hover or click a zone, state, or country. Switch the U.S. map between states and hardiness zones.
Highlighted USDA zones 10a–11b. Green countries can be grown outdoors.
United States
In range Too cold
World
Native Can be grown
Alaska and Hawaii are state outlines with their overall zone range. A country is painted if its mildest inhabited winter is at least one USDA step milder than this palm’s hardiness.
Scientific facts
- Archontophoenix cunninghamiana is the bangalow or piccabeen, often a bit hardier and common in California.
- The swollen lower trunk and silver leaflet undersides help separate alexandrae.
- Fast and hungry for water in heat. Dry sand without irrigation looks poor.
Get this palm
Other helpful resources
Full care guide
The king palm is the fast, smooth Australian feather palm with a green crownshaft, sold for tropical streets that still are not quite royal-palm country. USDA 10a to 11. Damage around 28°F (-2°C). It wants water and fertilizer. Dry neglect makes a thin tree.
Common Names:
King palm, Alexandra palm, northern bangalow palm.
Scientific Name:
Archontophoenix alexandrae (F.Muell.) H.Wendl. & Drude. The related bangalow palm is A. cunninghamiana.
Origin:
Northeastern Queensland, Australia.
Appearance:
A solitary feather palm with a smooth, ringed trunk (often slightly swollen at the base), a green crownshaft, and leaflets that are silvery beneath on alexandrae. The crown is full but not queen-palm plumose.
Growth Rate:
Fast in heat with water.
Max Growth Height:
40 to 70 feet in good conditions.
Foliage Spread:
About 10 to 15 feet.
Cold Hardiness and Hardiness Zone:
USDA 10a to 11. Around 28°F (-2°C) you get burn. Zone 9b is a sheltered gamble. Queen palm still has a bit more 9a street use. Cunninghamiana is the usual California Archontophoenix.
Soil Type:
Rich, moist, well-drained. Sand needs irrigation and fertilizer.
Fruit and Flowering:
Red fruit in hanging clusters. Messy on walks. Birds like them.
Can it Grow Indoors:
Only when young.
Light Requirements:
Full sun to light shade. Young plants like a little protection from blasting inland sun.
Water Requirements:
Even moisture. This is not a desert fan palm.
Maintenance Level:
Medium. Feed in the growing season with palm-specific fertilizer. Keep it watered in heat. Dropped fruit and old fronds are the mess.
Common Diseases/Pests:
Scale, mites in dry wind, and nutrient yellowing in sand. Fungal leaf spotting in still, wet shade.
Plant Care:
Sun, water, fertilizer, frost-free. If your winter still dips below the high 20s, look at queen, cabbage palmetto, or bangalow instead of forcing Alexandra king palm.
King palm Frequently Asked Questions:
1. King palm or bangalow?
Alexandrae is the tropical king. Cunninghamiana (bangalow) is common in milder California and often a safer outdoor choice there.
2. Faster than queen palm?
In heat and water it is competitive. It wants more tropical nights than a queen in zone 9a.
3. Can I grow it indoors?
A young plant in a bright atrium, not a long-term houseplant.
4. Why is it yellow?
In sand, potassium and magnesium first. Then check water. Do not answer every yellow palm with lawn nitrogen.
Plant a king palm where nights stay soft and the hose still reaches the tree. It is a fast tropical street palm, not a desert or zone 9a workhorse.