An old-fashioned favourite, popular in cottage-style gardens, Purity cosmos is a beautiful annual that will thrive with minimal care. Discovered in Mexico in the late 1700s, cosmos was brought back to Europe and it quickly became popular for its ease of cultivation and graceful appearance. The Purity cosmos is a naturally occurring white variation that was stabilized to produce stunning white flowers that appear in late spring and will bloom throughout the summer until early fall.
White Purity cosmos will reach about 3 to 5 feet tall at maturity, depending on the growing conditions. The plants have a feathery, fern-like foliage that bears an abundance of single, snow-white flowers. The 3-to-4-inch daisy-like petals are pure white with a bright yellow-golden disk in the centre.
Like other cosmos varieties, the plants can tolerate some drought and some shade, but they will produce healthier flowers with regular watering and lots of sun. Deadheading will promote more bloom. In fact, few plants are more productive per square foot than cosmos. The more you cut, the more they bloom. If the plants are started early in a well-drained and sunny area, then they might need stakes or support.
This annual is a great option to plug gaps in borders, as a background, for container gardening or as a feature in your garden. Purity cosmos is beloved by bees, birds and butterflies. The cut flowers last a long time and are a popular choice for weddings, as bouquets, centrepieces or floral arrangements.
- Latin Name: Cosmos bipinnatus
- Life Cycle: Annual
- Days to Maturity: 70-90
- Planting Depth: lightly press 4-5 seeds into soil
- Plant Spacing: 25-35 cm
- Growth Habit: 30-45 cm tall
GROWING INSTRUCTIONS
These easy-to-grow annuals are a popular garden flower for many reasons. Daisy-like in appearance, cosmos bloom quickly, attract bees, butterflies and birds and bloom through the fall. Coming in a variety of appealing colours, the blooms freely flower on top of tall, thin stems.
Seeds can be started indoors four to six weeks before the last frost. Plant in flats or individual pots. Germination should occur in 7-21 days. When seedlings reach 10-12 cm, transplant to larger pots or get them ready to move outside. When all danger of frost has passed, young cosmos can be gradually hardened off to prepare for transplanting into the garden.
Prepare the garden bed by loosening the soil 20 cm deep. Seeds can be spaced to recommended distance, or sown freely and thinned as they sprout and grow. Cover seeds lightly with soil and water well. Choose a site that receives full sun
Native to Mexico and Central America, cosmos will thrive in extreme heat with as much sunshine as possible. These heat-loving flowers prefer poor to ordinary soil, as long as it is well-drained. Planting in nutrient-rich soil could cause the plant to grow too much foliage instead of flowering, or they may get too tall and fall over. If this happens, stake tall plants or grow them close to each other for support.
When cosmos are established, they will only need to be watered if there are extreme drought conditions. If water supply is limited, cosmos will survive the longest without irrigation. Fertilizer is not recommended for cosmos. Feeding may lead to excessive foliage growth and stunted blooming. Cosmos are beautiful, yet durable, and very low-maintenance. They grow without much attention, will self-sow and don’t attract many problematic pests. If provided enough space in between plantings, proper airflow will help prevent diseases.
The only upkeep that cosmos really require is deadheading. This will prolong their blooming window and lead to more abundant flowering overall. If the plants seem to be getting out of control, they can be sheared back by about a third when most of the flowers have faded. This pruning will rejuvenate the plant and lead to a second growth of foliage and flowers. At the end of the season, cosmos can be cut to the ground or pulled out by the roots. Or, leave the plants in place if you’d like them to self seed. Cosmos usually bloom in 50-60 days and are perfect for cut flowers, adding elegance and colour to bouquets.
QUICK FACTS
- The flower is named after the Greek word ‘’Cosmos,’’ meaning harmony or balanced universe.
- Cosmos seeds will remain viable for 2 years if stored in a cool, dark place, ideally between 4 and 10⁰C. After that, the germination rate may start to go down.
OUR SEED GUARANTEE
You know that a lush, fruitful garden needs good soil, frequent watering, and sunlight to grow, but it’s the seeds that really make the harvest.
Picked and bagged for 2024 the vast majority of our seeds have germination rates of over 85%. The seeds are all-natural, non-GMO, non-hybrid, untreated, and open-pollinated for seed saving.
We have put a lot of thoughts into the design and packaging of our seed packets. Our seeds are all carefully packed in food grade kraft paper/aluminium zipper lock bags, and then are shipped in eco-friendly padded mailers.
We heat-seal each of our seed packet for even more protection from moisture, odour and light, allowing you to store your seeds for up to 3x longer than paper or plastic. Plant them all, germinate some indoors, save some for next season - it’s up to you!