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
Help us achieve our goals
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
hornwort cedar moss
coon tail fish blankets horn weed morass weed rigid hornwort
Ceratophyllum are submerged aquatic perennials with whorled, linear leaves more crowded near the stem apex, and tiny insignificant flowers in the leaf axils in summer
C. demersum is a submerged perennial with forked, dark green leaves, with tiny flowers in summer
EC Eur. to Afr.
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
Aspect North-facing or South-facing or East-facing or West-facing
Exposure Sheltered or Exposed
pHNeutral, Acid, Alkaline
Up to 10 cm
Time to ultimate height
Grow in water 30-90cm deep in full sun to shade. Plants float freely. Plants die back in winter but modified stem buds, turions, overwinter in bottom mud and re-grow in spring
Propagate by stem cuttings and allow to float in water
Suggested planting locations and garden types
Pruning No pruning required
Pests Generally pest free
Generally disease free
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
Buy from £10.5 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