Chocolate cosmos (Cosmos atrosanguineus)
Chocolate cosmos (Cosmos atrosanguineus) is a perennial plant that can grow 50cm – 1.5m tall and 10cm – 50cm wide. In this growing guide we’ll learn the cultivation details and how to plant Chocolate cosmos (Cosmos atrosanguineus).
This plant has several common names including: chocolate cosmos, black cosmos or black dahlia.
This is a deciduous plant that takes 2-5 years to reach full maturity.
In this article
Plant profile
Common name: chocolate cosmos, black cosmos, black dahlia
Scientific name: Cosmos atrosanguineus
Plant type: Perennials
Habit: Spreading / Branched
Height: 50cm – 1.5m
Spread: 10cm – 50cm
Foliage: Deciduous
Sunlight: Full Sun
Soil: Chalk, Loam, Sand
Moisture: Moist but well drained
Garden type: City & Courtyard Gardens, Informal Garden
Planting type: Cut Flowers, Flower borders and bedding
Seasonal colors
| Season | Stem | Foliage | Flower | Fruit |
|---|---|---|---|---|
| Spring | ||||
| Summer | ||||
| Autumn | ||||
| Winter |
How to plant Chocolate cosmos (Cosmos atrosanguineus) – I, KENPEI, CC BY-SA 3.0, via Wikimedia Commons
Perennial plants are one of the largest groups of plants.
They offer color, shape, fragrance and seasonal textures. The variety is such that there are plants to suit all sizes and styles of garden.
Traditionally, perennials are grown in borders, using a wall or hedge as a backdrop to bring out all their splendor during summer.
But since most gardens are not large enough for long borders dedicated exclusively to perennials, they are usually planted in mixed borders and beds, along with shrubs, annuals, biennials, and bulbs that extend the season of interest.
Other types of Cosmos to consider:
See all Cosmos
How to plant
In this section we will learn how to plant Chocolate cosmos (Cosmos atrosanguineus), know its needs in terms of soil, watering and sun exposure.
Soil
Chocolate cosmos (Cosmos atrosanguineus) is not a demanding plant regarding the type of soil and can grow in chalk, loam or sand.
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The chalky soil is pale and contains chunks of calcium-rich rock. It is a fertile and well-draining soil, almost always alkaline.
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The loam soil is dark, rich in organic matter but balanced in minerals. It offers the best of all worlds, retaining enough water for the plants, but allowing excess moisture to drain away. This is the most desired type of garden soil, perfect for most plants.
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Sandy soil is light, porous and very easy to drain. It is a soil poor in organic matter and nutrients. It is composed of relatively large mineral particles that allow water to drain quickly.
It is not very sensitive to soil acidity or alkalinity and grows well in soils with pH acid, alkaline or neutral.
Regarding drainage, Cosmos atrosanguineus likes to grow in moist but well drained soil.
Sunlight
Chocolate cosmos (Cosmos atrosanguineus) should be grown in full sun places.
Cultivation profiles – Growing Chocolate cosmos (Cosmos atrosanguineus) – Sten, CC BY-SA 3.0, via Wikimedia Commons
