Bird of paradise are tropical plants known for their brightly colored, distinctive flowers. There are around 40 different species of bird of paradise, the majority of which are native to New Guinea. Some species have been introduced as ornamental plants to tropical and subtropical regions around the world.
Bird of paradise thrive in warm, humid environments and are not well-suited to cold temperatures. As tropical plants, they can be damaged or killed by frosts and freezes. However, some species are more cold tolerant than others. Here we will explore how cold different species of bird of paradise can tolerate.
Natural Range Indicates Cold Tolerance
The natural range of a bird of paradise species provides clues about its cold tolerance. Species native to higher, cooler altitudes are more likely to be cold hardy than those restricted to hot, lowland areas.
For example, the Queen of Holland’s bird of paradise is native to montane cloud forests at elevations up to 3300 feet. Meanwhile, the Emperor bird of paradise inhabits lowland rainforests and does not thrive in cooler highland areas. Based on their native habitats, Queen of Holland’s bird of paradise is expected to have greater cold tolerance than Emperor bird of paradise.
Species like red bird of paradise and King of Saxony bird of paradise have a broad native range that spans cool mountainous areas and hot lowland forests. Their adaptability across varying habitats indicates an ability to withstand cooler temperatures.
On the other hand, Princess Stephanie’s astrapia and twelve-wired bird of paradise are confined to lowland tropical forests. Their narrow, heat-loving native range suggests sensitivity to cold.
USDA Hardiness Zones
The USDA Plant Hardiness Zone map divides geographical areas into zones based on their average annual minimum temperature. The zones provide guidance on which plants can survive winters in each region.
Looking at which zones a bird of paradise species can grow in gives a sense of its cold tolerance:
Species | USDA Hardiness Zones |
---|---|
Red bird of paradise | 10-12 |
King of Saxony bird of paradise | 10-12 |
Queen of Holland’s bird of paradise | 9-11 |
Emperor bird of paradise | 10-12 |
Princess Stephanie’s astrapia | 11-12 |
This shows that Queen of Holland’s bird of paradise, hardy to zone 9, has greater cold tolerance than Princess Stephanie’s astrapia which is only reliable down to zone 11.
Red bird of paradise and King of Saxony bird of paradise are intermediate in cold hardiness, surviving winters in zone 10, while Emperor bird of paradise needs zone 11 conditions.
Tolerance of Frost and Freezes
The ability of a bird of paradise species to withstand frosts and freezes also indicates its cold hardiness.
Queen of Holland’s bird of paradise can tolerate brief light frosts of a few degrees below freezing. Meanwhile, more tender species like Princess Stephanie’s astrapia or twelve-wired bird of paradise are likely to sustain damage even with light frosts.
Here are some examples of the frost tolerance of different bird of paradise species:
Species | Frost Tolerance |
---|---|
Red bird of paradise | May tolerate very light frosts of 30-32°F for short periods |
King of Saxony bird of paradise | Sensitive to frost |
Queen of Holland’s bird of paradise | Can handle light frosts in the high 20s°F |
Emperor bird of paradise | Likely damaged by frost |
As the table shows, Queen of Holland’s bird of paradise has the greatest frost tolerance, being able to survive brief temperatures in the 20s°F. Meanwhile, Emperor bird of paradise is easily damaged by frost. This matches expectations based on their native climates.
Actual Temperature Minimums
The lowest temperature a species has been recorded surviving provides a good indication of its cold hardiness limit. However, care must be taken to understand the context of the recorded low temperature (such as duration and plant health).
Here are some observed minimum temperature extremes for bird of paradise species:
Species | Recorded Low Temperature Survived |
---|---|
Red bird of paradise | 23°F for a few hours |
King of Saxony bird of paradise | 32°F for a short period |
Queen of Holland’s bird of paradise | 25°F for a brief period |
Emperor bird of paradise | 33°F for a couple hours |
These examples show Queen of Holland’s bird of paradise has survived the lowest recorded temperature, matching its high expected cold tolerance. Meanwhile, the tropical lowland Emperor bird of paradise succumbed to damage at a relatively mild 33°F.
Effects of Freezing Temperatures
When exposed to freezing temperatures they cannot tolerate, different bird of paradise species exhibit varying degrees of damage. Cold sensitivity determines how quickly and severely the plants are affected.
Tropical lowland species like Princess Stephanie’s astrapia can experience leaf burn, stem dieback, and failed bloom at just 2-3 hours below 35°F. Highland mountain species like Queen of Holland’s bird of paradise may only exhibit minor tip burn after 12 hours at 25°F.
Leaf and flower damage is usually the first sign of cold injury. Prolonged freezing causes progressive dieback of stems and roots. Severe freezes that drop temperatures well below a plant’s tolerance limit can kill the entire plant.
Physiological factors like water content affect freeze damage. Well-watered, actively growing plants are most vulnerable. Plants already stressed by drought may better tolerate cold snaps.
Here are examples of freeze damage in different bird of paradise species:
Species | Freeze Damage |
---|---|
Red bird of paradise | Leaf burn at 28°F; stem dieback at 25°F |
King of Saxony bird of paradise | Flower damage at 33°F; extensive leaf and stem damage below 30°F |
Queen of Holland’s bird of paradise | Minor tip burn after several hours at 25°F |
Emperor bird of paradise | Severe leaf and stem damage after a few hours below 34°F |
Again, this illustrates the relatively high cold tolerance of Queen of Holland’s bird of paradise compared to more tropical species.
Caring for Plants After Freezing
Proper care after freeze damage occurs is vital for recovery. Once frozen, plants should not be pruned until warmer weather returns. Pruning stimulates new growth that can be damaged by subsequent frosts.
Plants may appear dead after freezing but may re-sprout from the roots. Leaving stems intact until the danger of frost has passed allows plants the chance to regenerate. Sheltering plants and elevating pots off cold ground helps protect root zones.
Damaged leaves and spent flowers can be removed to divert energy to new growth. Water should be withheld until growth resumes to prevent root rot. Fertilizer can encourage regrowth but avoid over-fertilizing weakened plants.
When warmer weather returns, gently trim back dead stems and leaves. Remove badly damaged foliage but avoid overpruning. Apply a balanced fertilizer and resume regular watering to support recovery.
With proper aftercare and favorable conditions, plants may rebound surprisingly well even following significant freeze damage. Bird of paradise’s resilience helps account for their enduring popularity.
Protecting Plants from Freezes
Gardeners in marginal climates should take precautions to protect more sensitive bird of paradise varieties from potential freezes:
– Cover plants overnight using fabric row cover, plant blankets, etc. Remove coverings during daytime.
– Place smaller potted plants in a protected location like an unheated garage or under an overhang.
– Wrap above-ground stem and crown areas with insulation. Avoid crowding mulch against stems.
– Water well before a freeze but avoid overwatering. Dry plants are more cold tolerant.
– Apply antidesiccant spray to leaves to reduce freeze damage.
– Install heat lamps, heat cables, or other heating devices for additional protection.
With extra care, gardeners can stretch the cold-hardiness limits of bird of paradise in their region. But take care not to expose treasured plants to below-freezing temperatures they cannot tolerate.
Key Factors in Cold Tolerance
Understanding why some bird of paradise tolerate cold better than others requires examining key physiological factors:
Native Climate
Species from higher altitude tropics evolved protections against cooler night temperatures. Lowland forest plants did not develop cold adaptations.
Genetic Variability
Some varieties have inherent genetic capacity to withstand chill that others lack. Selective breeding can enhance cold tolerance.
Plant Health
Vigorously growing, unstressed plants are most vulnerable to freeze damage. Weak or drought-stressed plants may survive lower temperatures.
Foliage and Stem Structure
Thicker, smaller leaves resist cold better than broad, thin leaves. Leaf hairs and waxy coatings protect against frost. Woody stems insulate vascular tissues.
Chemical Antifreezes
Some plants accumulate glucose, proteins, or other compounds that lower freezing point of cell fluids.
Avoiding Intracellular Freezing
Resilient cell membranes prevent destructive ice crystal formation within cells during freezing.
Adaptive Mechanisms
Processes like leaf folding or downward growth of shoots shield tissues from cold exposure.
Understanding these cold tolerance factors helps explain why highland bird of paradise species generally withstand much lower temperatures than lowland varieties.
Ideal Climate Conditions for Growth
While bird of paradise tolerate a range of conditions, they thrive best under certain optimal growing circumstances:
Warm Temperatures
Ideally daytime highs of 70-85°F and nighttime lows above 60°F. Temperatures under 50°F slow growth.
High Humidity
Prefer consistent 60% humidity or higher. Low humidity stresses plants.
Moisture
Soil should be kept evenly moist but not waterlogged. Avoid dry spells.
Bright Light
At least 4-6 hours direct sun daily. More sun promotes blooms.
Shelter from Wind
Protect from dessicating, cold winds which damage broad tropical leaves.
While less than ideal conditions can be tolerated, meeting these optimal requirements ensures happy, rewarding plants. Give bird of paradise conditions similar to their lush, equatorial homeland.
Conclusion
In their native habitat, bird of paradise species are accustomed to warm, frost-free conditions year-round. Yet some types tolerate occasional light frosts and brief freezing better than others. Factors like native climate, genetics, and structural adaptations determine cold hardiness. Tropical lowland species are the most cold sensitive. With protective measures, certain resilient varieties can survive colder temperatures than expected. But all bird of paradise perform their best in warm, sheltered, humid environments similar to the lush tropics that they call home. With the right care, even gardeners in sub-tropical climates can achieve spectacular, distinctive blooms.