{Almost} Wordless Wednesday :: Cosmos

Posted on: August 26th, 2015 by Trillium Art


Brrr! This morning’s walk around the yard definitely did not feel like summer! My containers look tired after the heat of the summer and even the recent rains hasn’t brought them back. But, before I turn the focus of this blog to the next season, I wanted to share a wonderful summer annual that I have often taken for granted – the Cosmos.

My past garden always had bright and cheerful cosmos. I grew them in and around a limestone boulder retaining wall. Their soft, fine textured leaves contrasted beautifully with the harsh stone. They are easy to grow and work well in both the garden and in containers.


Cosmos can be grown from seed indoors, 4-6 weeks before the last spring frost. The seedlings grow quickly so transplanting to larger pots can be done when they are 4” tall. After the last frost they can be planted outside either as seeds or as transplants. Be sure to plan ahead as they take about 7 weeks to bloom after germination. But once they get started, they will continue to bloom all summer until the fall frosts.

These flowers are often part of a traditional cottage garden design and perfect for informal gardens. The taller varieties can be used at the back of the border and to help screen an undesirable view. The medium-sized plants look great in the centre of an island bed to provide height and texture. The smaller plants work well at the front of the border or in containers. Cosmos are also an essential plant in butterfly and cut flower gardens.


As with most plants, by removing the dead or faded blooms (deadheading) prolongs flowering. It also helps to encourage lower branching and therefore create a stronger stem. However I played hide and seek with a female finch as she darted from seedhead to seedhead, so there are benefits to not deadheading at all!


Keep an eye on the garden where you plant them as they can self-seed so you may end up with more than you bargained for!

I have not planted them in the new garden yet, but when I saw this island display at the Dufferin Garden Centre, I realized I missed them! They have definitely made the list for next year!

Do you grow cosmos in your garden? Where do you include these silky flowers?


Zone: 10 (annual but will self-seed)

Light Conditions: full sun

Soil: tolerate poor to average soil that has not been heavily amended

Height: 18” – 60”, depending on the variety (taller plants may need staking)

Foliage: lacy foliage similar to ferns or asparagus

Flower Power: daisy-like flowers from 2-4” may be open or bowl-shaped on the top of long stems in colours of magenta, yellow, orange, pink or white

Tips: attracts butterflies, bees and birds, great cut flower, low maintenance

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