Off-Season Bloomers: Plumerias That Flower in Fall or Winter

While plumeria is typically known for its spring to summer bloom cycle, some varieties are capable of flowering in the off-season, extending the bloom period into fall or even winter. For collectors and plumeria enthusiasts, these off-season bloomers offer a unique way to enjoy the vibrant fragrance and color of plumeria outside of the traditional blooming season. In tropical climates and with the right environmental conditions, plumeria can surprise you with a second (or even third) bloom cycle.

In this article, we’ll explore the varieties that are known for fall or winter blooming, how to force a second bloom cycle, and tips for maintaining blooming through the cooler months, whether you’re growing plumeria indoors or in a greenhouse.

1. Off-Season Bloomers: Varieties That Flower in Fall or Winter

While plumerias are naturally seasonal bloomers, some varieties have been known to extend their bloom season under certain conditions. In tropical locales or controlled environments like greenhouses, certain plumeria cultivars can continue to bloom into fall or even winter, when most other plumeria plants are in dormancy.

1.1 Singapore Obtusa Varieties (Plumeria obtusa)

One of the most well-known off-season bloomers are the Singapore obtusa varieties. Plumeria obtusa, particularly the ‘Singapore White’, is known for its ability to bloom year-round or during the off-season in tropical and greenhouse conditions.

Blooming Characteristics:

• Flower Color: Singapore obtusa varieties typically produce white flowers with a subtle yellow center and a sweet, jasmine-like fragrance.
• Blooming Cycle: In tropical climates or controlled environments, these plumerias can bloom continuously or have multiple bloom cycles throughout the year, even into the fall or winter.

How to Encourage Fall/Winter Blooms:

• Provide Warmth: Singapore obtusa thrives in warm temperatures, so ensure the plant is kept at 70°F (21°C) or higher during cooler months.
• Lighting: If growing indoors or in a greenhouse, use grow lights to extend the daylight hours and stimulate flower bud development during the fall and winter months.

1.2 Thai Plumeria Cultivars

Some Thai cultivars have been selectively bred to produce off-season blooms, making them a great option for plumeria collectors looking to extend the blooming period. These cultivars are more resilient to temperature changes and can flower during cooler periods of the year.

Blooming Characteristics:

• Flower Color: These varieties often produce vibrant, multi-colored blooms, including pink, red, and yellow flowers with a strong frangipani fragrance.
• Flowering Cycle: Thai plumerias can bloom late into the year, with some even blooming during fall or winter, especially when grown in greenhouses or under temperature-controlled conditions.

How to Encourage Fall/Winter Blooms:

• Greenhouse Growing: Keep Thai plumeria cultivars in a greenhouse where temperature and humidity can be controlled. This will encourage the plant to bloom outside of the typical growing season.
• Consistent Watering and Feeding: Provide regular watering and use a balanced, high-phosphorus fertilizer to support continued flower production.

2. Forcing a Second Bloom Cycle: Light and Warmth in Autumn

Even plumeria varieties that typically bloom in the spring and summer can be coaxed into producing a second bloom cycle by manipulating light and temperature during the fall. Greenhouse growers and experienced plumeria enthusiasts often use this technique to keep their plants blooming for longer.

How to Force a Second Bloom Cycle:

• Increase Light Exposure: Plumerias require at least 6-8 hours of direct sunlight to bloom. During fall and winter, extend the daylength with grow lights to encourage flower bud formation. Keep the lights on for 10–12 hours a day to simulate longer days.
• Provide Warmth: Keep plumerias at a consistent temperature of 65–75°F (18–24°C). Plumeria plants will bloom more readily when temperatures are kept warm, even during cooler months.
• Maintain Consistent Care: Just like the main blooming season, regular watering, fertilizing, and avoiding over-watering are key to encouraging blooms. Use a high-phosphorus fertilizer to promote flowering and avoid excess nitrogen, which promotes leaf growth at the expense of flowers.

3. Greenhouse Growing: Creating an Optimal Environment for Off-Season Blooming

For those who want to grow plumerias year-round, a greenhouse offers the perfect solution. By controlling temperature, humidity, and light, you can create an environment that encourages plumerias to bloom beyond their typical growing season.

Benefits of Greenhouse Growing:

• Controlled Temperature: Greenhouses allow you to maintain a consistent temperature that supports year-round growth and blooming.
• Extended Growing Season: A greenhouse extends the growing season and prevents the plant from entering dormancy too early, allowing it to continue producing blooms during fall and winter.
• Light Control: Using grow lights in combination with natural sunlight in a greenhouse helps stimulate flower bud development in off-season months.

Greenhouse Care Tips for Off-Season Bloomers:

• Temperature Control: Keep the greenhouse temperature between 70°F and 80°F (21°C to 27°C) to promote flower production.
• Humidity Management: Plumeria plants prefer moderate humidity. Ensure good airflow and avoid excessive moisture that could lead to fungal growth.
• Fertilization: Continue with high-phosphorus fertilizers to encourage blooms, and reduce nitrogen use to avoid excessive leaf growth.

4. Conclusion: Extending the Plumeria Bloom Season

While plumeria plants are not naturally year-round bloomers, certain cultivars, especially Singapore obtusa types and some Thai hybrids, can flower in the off-season with the right care. Growing plumeria in greenhouses or providing controlled light and temperature can help induce fall or winter blooms, allowing you to enjoy plumeria flowers even when temperatures are cooler.

By understanding your plumeria’s natural bloom cycle and using techniques like greenhouse growing, light manipulation, and temperature control, you can enjoy extended blooming and maximize the flowering potential of your plants.

Whether you’re growing plumeria for year-round blooms in a tropical setting or want to encourage a second bloom cycle in cooler climates, these tips will help you get the most out of your plumeria and keep it blooming well into the fall and winter.