Help us achieve our goals:
make a donation »
Join the RHS today and support our charity
Free personalised gardening advice
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Make a donation
I have forgotten my password
Keep me signed in
Register for free to receive our newsletters, add comments to blogs/articles and to save content.
See what events are on near you and browse your bookmarked pages.
We have combined these two powerful search tools into a single Find a Plant service searching over 250,000 plant records.
Virtually all of the features of the old searches are still available and in addition we have added several new features to create a more comprehensive and user friendly search experience.
When using this search
Search by plant name, key attributes or both to find plant details and a list of
AGM plants have been through a rigorous trial and assessment programme. They are:
This plant will provide nectar and pollen for bees and the many other types of pollinating insects.
It is included in an evolving list of plants carefully researched and chosen by RHS experts. Divided into 3 groups these lists, linked below, are maintained by a team of RHS staff and are reviewed annually.
© RHS 2002
the RHS today and get 12 months for the price of 9
Other common names
chocolate cosmos black cosmos
Bidens atrosanguinea Cosmos atrosanguineus 'Chocolate'
Cosmos diversifolius atrosanguineus
Cosmos can be annuals or perennials with simple or pinnately divided leaves and large, long-stalked daisy-like flowers in summer
C. atrosanguineus is a spreading tuberous perennial, with pinnately divided leaves and bowl-shaped, chocolate-scented, maroon-crimson flower-heads in late summer
Habit Spreading / Branched
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
Aspect South-facing or East-facing or West-facing
Exposure Exposed or Sheltered
MoistureMoist but well-drained
SoilLoam, Chalk, Sand
pHAcid, Alkaline, Neutral
Time to ultimate height
Grow in a moderately fertile, moist but well-drained soil in full sun. Mulch in autumn; in cold areas lift tubers before first frosts and keep frost-free over winter.
Propagate by taking basal cuttings in early spring and providing bottom heat
Suggested planting locations and garden types
Flower borders and beds Cut Flowers
City & Courtyard Gardens Cottage & Informal Garden
Pruning Deadhead to prolong flowering
Pests Generally pest free
May suffer from foot rot and grey moulds
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
Buy from £5.99 at the RHS Plants Shop
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.
Join the RHS today and get 12 months for the price of 9