Cosmea 'Versailles Dark Rose' Cosmos bipinnatus 'Versailles Dark Rose'

Water

The Garden Cosmos or Mexican Aster should be watered regularly to maintain consistent moisture, especially during dry spells. Aim for about 1 inch of water per week, which can be adjusted depending on rainfall and temperatures. Deep watering encourages deeper root growth, so it's better to water thoroughly a few times a week rather than a little every day. During the hottest parts of summer, additional water might be necessary. Always check the top inch of the soil; if it's dry, it's time to water. Overwatering can lead to root rot, so ensure good drainage.

Light

Garden Cosmos thrive in full sun conditions, meaning at least 6 to 8 hours of direct sunlight daily. They perform best when planted in a spot where they receive unfiltered sunlight throughout the day. These plants are ideal for sunny borders or open areas where there is minimal shade. Avoid placing them in spots that receive a lot of shade or filtered light to ensure optimal growth and flowering.

Temperature

The ideal temperature range for Garden Cosmos is between 60 to 85 degrees Fahrenheit. They can survive minimum temperatures down to about 25 degrees Fahrenheit but will not survive frost or freezing conditions. Garden Cosmos can tolerate high summer temperatures well, as long as they are appropriately watered. However, consistently high temperatures above 90 degrees may stress the plants, especially if accompanied by prolonged drought.

Pruning

Pruning Garden Cosmos is primarily done to promote bushier growth and more blooms. Deadheading, or removing spent flowers, encourages further blooming throughout the season. Cut the stems back to the first leaf below the dead flower to maintain an attractive shape. Additionally, you can prune Cosmos in midsummer by cutting the plants back by about one-third to refresh the plant and encourage fall blooming. Pruning is typically needed every few weeks during the flowering season.

Cleaning

As needed

Soil

The Cosmos, commonly known as the Garden Cosmos or Mexican Aster, thrives in a well-draining soil mix with compost and peat for nutrients and moisture retention. The best pH for this soil mix should be slightly acidic to neutral, between 6.0 and 7.5.

Repotting

Garden Cosmos plants, being annuals, are not typically repotted as they complete their life cycle within one year and then reseed or are replaced.

Humidity & Misting

The Garden Cosmos prefers moderate humidity levels but is quite adaptable and can thrive in the average humidity of an outdoor environment.

Suitable locations

• Indoor

  Place in bright indirect light, ensure good airflow, and use a well-draining pot.

• Outdoor

  Plant in full sun, water regularly and use well-draining soil.

• Hardiness zone

  2-11 USDA

Life cycle

The life of Cosmos bipinnatus 'Versailles Dark Rose', commonly known as the Cosmos or Mexican aster, begins with seed germination, which generally occurs in warm soil after the last frost of spring. The seedlings emerge and develop true leaves, entering the vegetative growth stage where they form a bushy structure with finely divided, feathery foliage. As the plant matures, flowering begins in the summer, showcasing its vibrant dark rose pink flowers that attract pollinators such as bees and butterflies. The blooming period can last until the first frost of autumn, during which flowers continuously develop into seed heads. After pollination, the plant sets seeds that are dispersed by wind or self-sow to propagate the next generation. The plant is typically an annual and completes its life cycle within one growing season, dying back after seed set, though it may reappear the following year from self-sown seeds if conditions are favorable.

Propogation

• Propogation time

  Spring to early summer

• Cosmos bipinnatus 'Versailles Dark Rose', commonly known as Cosmos, is typically propagated by seed, which is both convenient and efficient. Propagation is best done in the spring after the last frost when outdoor temperatures become reliably warm. To propagate by seed, simply scatter the seeds on the surface of a well-draining soil mix in either a seed tray or directly in the garden where you want the Cosmos to grow. Lightly press the seeds into the soil as they need light to germinate, but don't cover them with soil. Keep the soil moist but not waterlogged until germination, which usually occurs within 7 to 10 days. Once seedlings have developed a few sets of true leaves and are strong enough to handle, they can be thinned out or transplanted to give them adequate space to grow.