Fabulous, rich velvety-maroon-to-almost-black, chocolate-scented flowers open over a very long period from early summer right into the frosts of autumn. Amazed growers cannot resist smelling this wonderful perfume which comes from a chemical constituent very similar to vanilla! Although available for many years as sterile plants, viable seeds have never been produced, but after a spontaneous mutation occurred, one plant was discovered with just a few fertile seeds, and plants grown from these seeds will also produce a small number of fertile seeds. Incredibly, these plants vary in stature and colour of flower, some being very dark, almost black, as illustrated! Mature plants vary from tight compact clumps with short-stemmed blooms, up to large branching beauties with very long stemmed flowers which are ideal for cutting. Flowers range from small to opulently-large, whilst the fragrant petals vary from notched or feathered to oval and entire, as shown in the picture. Just a few named clones currently exist, one of which is known in the trade as ‘Chocamocha’ a beautiful, top-selling dwarf form of this plant which has redder petals than many of the forms these seeds will produce. Originally from Mexico, this rare and lovely plant is now described as extinct in the wild, but you now have the opportunity to grow your own new variety. We collect laboriously by hand, and one at a time, just a very small limited number of good fertile seeds of this legendary and incredibly valuable plant, hence the very high price. … Learn More

Chocolate cosmos (Cosmos atrosanguineus)

Among the garden plants grown for their scent, chocolate cosmos (Cosmos atrosanguineus) certainly stands out from the crowd. Yes, as its common name suggests, its flowers really do smell like chocolate, especially at the end of a sunny day. The aroma comes from the vanillin that the flower produces… the same substance that gives cocoa its characteristic odor.

Besides, the little flowers are such a dark red (the name atrosanguineus means dark blood red) they can also be said to be chocolate colored… at least, if you use a bit of imagination. After all, they are certainly as chocolate-colored as red velvet cake and it is a type of chocolate cake. The flowers are at their darkest and most chocolaty color when they open, becoming dark wine red over time.

Description

Chocolate cosmos has pinnate leaves and reaches 30 to 60 cm in height. It resembles the well-known sulfur cosmos (Cosmos sulphureus), a popular garden annual, whose flowers are about the same size (about 1 to 1 ¾ inches/2 to 3 to 4.5 cm in diameter) and of the same shape (6 to 10 ray flowers surrounding a raised central disc), but yellow or orange.

You’ve probably seen chocolate cosmos in garden centers: it’s been available for decades, showing up every now and then, usually in the form of tuberous roots offered for sale with other summer bulbs (dahlias, gladioli, cannas, etc.), more rarely in the form of a blooming plant.

Extinct in the Wild

Old Thompson & Morgan catalog

Chocolate cosmos is said to have been introduced by William Thompson, founder of the renowned Thompson & Morgan seed company, back in 1902, from seeds harvested from the wild in the Zimapán region of the state of Hildago, Mexico. It has never been found since and is now considered extinct in the wild.

With its sweet and intriguing fragrance, chocolate cosmos quickly became a popular garden plant in Europe early in the 20th century, but like so many other plants, essentially disappeared from culture during the First World War. If it even survives today, it was because horticulturists at Kew Gardens, the famous British botanical garden, managed to keep a single clone alive right through the war. Until recently, therefore, all the chocolate cosmos grown anywhere in the world came from this single clone. And that causes a problem.

You see, chocolate cosmos, like so many plants, is self-sterile: it will not produce fertile seeds when pollinated with its own pollen. Since all the plants in cultivation were identical (they all derive by vegetative propagation from Kew Gardens’ single surviving specimen), pollinating flowers was a waste to time. No viable seeds could be produced. So for almost 100 years, all chocolate cosmos plants were clones produced by division or micropropagation and considered sterile. There was no way of producing better quality cultivars, notably ones with more flower power.

A Surprise From Down Under

Until recently, all chocolate cosmos were clones. Photo: Philippe Giabbanelli, Wikimedia Commons

Given that the one existing clone of chocolate cosmos was considered self-sterile, it was quite a surprise to learn that hybrids with superior flowering traits were being produced in New Zealand. Back around 1990, it would appear a single plant produced a few fertile seeds. The plants resulting from these seeds were no longer clones, but varieties with their own DNA. The differences between them may have been minor, since they all came from a single mother, but nevertheless each seedling was sufficiently different that they could cross readily with other plants. A first cultivar, Cosmos atrosanguineus ‘Pinot Noir’, was released locally by Russell Poulter in 1996, followed by others, although none attracted much international attention.

That has now changed. Hybridization programs continue in New Zealand and now also in Germany and Japan and new cultivars that are more floriferous and easier to grow are being released. There are now at least 4 cultivars raised by tissue culture that are available to gardeners in Europe: ‘Choca Mocha’ or ‘Chocamocha’ (30 cm), ‘Dark Secret’ (50 cm), ‘Eclipse’ (45 cm) and ‘Spellbound’ (60 cm).

Chocolate cosmos ‘Choca Mocha’ is a new dwarf clone of the old-fashioned chocolate cosmos. Photo: Proven Winners

North American gardeners will find it easiest to get their hands on ‘Choca Mocha’. It’s a dwarf variety 30 cm tall and is offered by Proven Winners. It came out last year in limited distribution and will be more widely available in 2017. That still doesn’t mean it will necessarily make it to your local garden center right away, though, so you might want to consider ordering it by mail order from nurseries like Phoenix Perennials in Canada and Burpee in the United States.

Or Raise It From Seed

Cosmos atrosangineus ‘Black Magic’: note the variability in the flowers. Photo: Jelitto Staudensamen GmbH

Seeds of fertile varieties of cosmos chocolate are now available as well. Jelitto Perennial Seeds, a German wholesale seed supplier, introduced their seed strain, ‘Black Magic’, claimed to be the result of 10 years of hybridizing, in 2016. It’s now available from Chiltern Seeds and other seed companies… although it’s very expensive. The plants will be variable, with large or small flowers, rounded or notched rays, broad or narrow rays, various shades of dark red, a chocolate or vanilla fragrance and a height of between 1 and 2 feet (30–60 cm).

Of course, once you’ve found a plant that suits your needs, you can simply multiply it by dividing the tuberous roots each spring.

Chocolate cosmos is easy to grow from seed. Just start it indoors like any cosmos, about ¼ inch (5 mm) deep, 4 to 6 weeks before there is no longer any danger of frost in your area and grow in bright light to full sun under normal indoor temperatures.

In the Garden

Plant chocolate cosmos outdoors in full sun or partial shade in any well-drained soil, spacing the plants 12 to 16 inches (30-40 cm) apart. It grows well both in the garden and in containers. It needs no special summer care except watering during periods of drought. You’ll find it will bloom best if you deadhead regularly.

Since this plant is not cold hardy (zones 10 to 11), you can either consider it to be an annual and let it freeze or bring the tuberous roots indoors in the fall, treating them in the same way would dahlia tubers, that is, storing them dry in a cool spot. The two tubers are, in fact, actually very similar in appearance.

I can guarantee one thing: unlike real chocolate, chocolate cosmos is absolutely nonfattening!

Caring For Chocolate Cosmos Plants: Growing Chocolate Cosmos Flowers

Chocolate isn’t just for the kitchen, it’s also for the garden – especially a chocolate one. Growing chocolate cosmos flowers will delight any chocolate lover. Read on to learn more about growing and caring for chocolate cosmos in the garden.

Chocolate Cosmos Info

Chocolate cosmos flowers (Cosmos atrosanguineus) are dark reddish brown, almost black, and have a chocolate scent. They are relatively easy to grow, make wonderful cut flowers and attract butterflies. Chocolate cosmos plants are often grown in containers and borders so their color and scent can be fully enjoyed.

Chocolate cosmos plants, which are native to Mexico, can be grown outside as a perennial in hardiness zones 7 and above. It can also be grown outside as an annual, or in containers and overwintered inside in colder climates.

Propagating Chocolate Cosmos Plants

Unlike most other cosmos flowers, chocolate cosmos are propagated by their tuberous roots. Their seeds are sterile, so planting chocolate cosmos seeds will not get you the plants you desire.
Look for roots that have an “eye” or new growth on them to start new plants.

If you are growing chocolate cosmos flowers as an annual, the best time to look for this is when you dig them up in the fall. If you are growing chocolate cosmos flowers as a perennial, every couple of years you can dig them up and divide them in early spring.

Caring for Chocolate Cosmos

Chocolate cosmos plants like fertile, well-drained soil and full sun (6 hours of sunlight a day).

Too much water will cause the roots to rot, but a once a week deep watering will keep them healthy and happy. Make sure to let the soil dry out between waterings; remember that chocolate cosmos flowers originated in a dry area.

Once a bloom has died, the plant will greatly benefit from it being removed, so be sure to deadhead the cosmos regularly.

In warmer climates, where they are grown as perennials, chocolate cosmos plants should be heavily mulched during the winter. In colder climates, where chocolate cosmos plants are grown as an annual, they can be dug up in the fall and overwintered in a frost free area in slightly moist peat. If they are in a container, be sure to bring them inside for winter.

There are many chocolate colored flowers available, but Chocolate Cosmos gets a special boost. I give it this rating because, not only does it have a lovely dark chocolate fragrance, but it is also one of the top 10 rarest flowers in the world. The plant is a perennial and is easy to grow and a stunner in the garden.

Imaging walking through your garden and getting a whiff of dark chocolate with a hint of vanilla wafting from a pretty chocolate colored flower. You have just happened upon a chocolate cosmos!

Chocolate Cosmos has a lovely Chocolate color and Dark Chocolate Fragrance.

This variety of cosmos is a native to Mexico, but has been extinct in the wild for over 100 years.

Photo credit: Ali Express

Chocolate cosmos (Cosmos atrosanguineus) is a perennial plant with a fleshy tuberous root. The flowers are red to maroon brown with a center raised area. The plant has a dark chocolate fragrance that becomes more noticeable as the day wears on.

The center of the flower forms in a cluster like appearance and opens into the traditional cosmos shape with velvety petals. Once the flower has died, the plant will benefit from deadheading, which will encourage additional blooms.

Once open, the flower has a cupped appearance but keeps the stunning cluster center that makes it so interesting. The color can vary from reddish brown to deep chocolate.

Photo credit Flickr – Tanaka Juuyoh

If you can find a plant, it is fairly easy to grow, as are all Cosmos. Chocolate Cosmos can get by on rather dry soil, as long as it is amended. Avoid waterlogged conditions, or the tubers will rot.

Chocolate cosmos makes wonderful cut flowers and does a great job at attracting butterflies to your garden. The Clumps get larger with each passing year. The plant likes lots of sun and a well draining soil. It is hardy to about 20 degrees but can be dug up and stored for the winter the way you do with dahlias.

Raised beds and organic mulch help to maintain even moisture. Propagation is by division of the tubers. This is best done in early spring or fall.

Chocolate cosmos should be grown in a border or in containers where the flowers and fragrance can be appreciated up close. They make very good cut flowers.

This plant comes with both good and bad news. The good news is that it is a perennial, so once you find one you don’t have to replace it every year (as long as you dig it up and save it). The bad news is that it doesn’t throw fertile seeds, so this plant only propagates by its roots.

I grew cosmos for the first time a few summers ago. It is prolific when it comes to bearing flowers and a delight in my garden.

Chocolate Cosmos (Cosmos atrosanguineus), as a plant, can be found in limited amounts for sale at Burpee, New Garden Plants, and Joy Creek Nursery. I have seen seeds for sale on Amazon, but cannot vouch for them, since the plant throws infertile seeds. Another plant which is available as seeds is Osiria rose , which are sold on Amazon, and likely will not grow.

Have you had any luck growing Chocolate Cosmos?

Disclosure of Material Connection: Some of the links in the post above are “affiliate links.” This means if you click on the link and purchase the item, I will receive a small commission from the sale, but the price is the same for you. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: “Guides Concerning the Use of Endorsements and Testimonials in Advertising.”

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