Cosmea 'Sonata White' Cosmos bipinnatus Sonata White = 'Pas1789' (Sonata Series)

Water

Cosmos, commonly known as Garden Cosmos, should be watered regularly to keep the soil consistently moist, especially during dry spells. For established plants in the ground, aim to water deeply once a week with about one to two gallons of water, depending on the weather conditions. Container-grown Cosmos may require more frequent watering, possibly every couple of days, due to soil drying out faster in pots. Avoid overhead watering to reduce the risk of fungal diseases and instead direct water to the base of the plant. During particularly hot or windy weather, check the moisture level of the soil more often, as the plants may need additional water.

Light

Garden Cosmos thrives in a spot with full sun exposure where it can receive at least 6 to 8 hours of direct sunlight per day. Though it can tolerate some light shade, the plant performs best and produces more abundant blooms when planted in a location with maximum sunlight.

Temperature

The ideal temperature range for Garden Cosmos is between 60 to 90 degrees Fahrenheit. They can tolerate a minimum nighttime temperature of around 50 degrees Fahrenheit but may suffer if temperatures drop significantly below this. Garden Cosmos are heat-loving plants and can endure high temperatures well, as long as they are watered adequately.

Pruning

Pruning Garden Cosmos encourages bushier growth and more blooms. Deadhead spent flowers regularly to promote continuous flowering throughout the season. Cut back any leggy stems to about one third their length to maintain plant shape and encourage new growth. The best time for more extensive pruning or cutting back is in midsummer, after the first wave of blooming has finished.

Cleaning

As needed

Soil

For the Cosmos (Garden Cosmos or Mexican Aster), the best soil mix is light, well-draining, and fertile with a pH between 6.0 to 8.5. A combination of loam, peat, and sand or perlite can provide the necessary drainage and nutrient content for optimal growth.

Repotting

Cosmos, as annuals, generally do not require repotting. They complete their lifecycle in one season and are best sown directly into the garden or started in temporary containers and transplanted outside after the last frost.

Humidity & Misting

Cosmos plants, being drought-tolerant, prefer moderate to low humidity levels. They thrive in outdoor conditions where the humidity naturally fluctuates, without the need for specific humidity adjustments.

Suitable locations

• Indoor

  Provide bright light and well-draining soil for Cosmos indoors.

• Outdoor

  Plant in full sun and well-draining soil after last frost.

• Hardiness zone

  Cosmos are generally grown as annuals and do not have specific USDA hardiness zones, but they perform well during the warmer months across zones.

Life cycle

Cosmos bipinnatus Sonata White begins its life cycle with seed germination, occurring in warm soil with temperatures around 70-85°F (21-29°C). The seedlings soon emerge, developing true leaves and establishing a root system. As the plant matures, it grows into a bushy annual with fine, feathery foliage and stems that can reach up to 2 feet in height. The next stage is marked by the blooming of large, pure white flowers with a bright yellow center throughout the summer until the first frost. Following pollination, the flowers produce seeds housed in slender capsules, ensuring the perpetuation of the next generation. Finally, as an annual, the plant completes its life cycle and dies with the onset of winter, relying on the dispersed seeds to spawn new plants the following season.

Propogation

• Propogation time

  Spring to early summer

• The most popular method of propagation for Cosmos, specifically the Cosmos bipinnatus Sonata White from the Sonata Series, is through seed. Sowing seeds can be done directly in the garden after the last frost when the soil has warmed to at least 60 degrees Fahrenheit (15.6 degrees Celsius). To promote better germination, seeds should be sown shallowly, only about 1/4 inch (about 6 millimeters) deep, and spaced a few inches apart. They generally prefer full sun and well-draining soil. Seedlings usually emerge within 7 to 10 days. After germination, thin the seedlings to about 12 to 18 inches (30 to 45 centimeters) apart to give each plant ample space to grow. This method is straightforward and cost-effective, making it perfect for gardeners of all levels.