homebanner homebanner homebanner homebanner homebanner homebanner
Hydrilla verticillata - (L.f.)Royle.
Common Name Hydrilla, Waterthyme
Family Hydrocharitaceae
USDA hardiness 4-8
Known Hazards None known
Habitats Grows in a variety of aquatic habitats, from acidic to basic, oligotrophic to eutrophic, fresh to brackish, and from a few centimeters deep to a meter or more if light penetrates that deeply[270].
Range A cosmopolitan plant, it is hard to know the areas where it is truly native[270]..
Edibility Rating  
Other Uses  
Weed Potential Yes
Medicinal Rating  
Fully Hardy Water Plants Full sun


Hydrilla verticillata Hydrilla, Waterthyme

Hydrilla verticillata Hydrilla, Waterthyme
Physical Characteristics
Hydrilla verticillata is a ANNUAL/PERENNIAL at a fast rate.
It is hardy to zone (UK) 5. It is in flower from May to October, and the seeds ripen from Jun to October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Water.Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: neutral and basic (alkaline) soils and can grow in very alkaline soils.
It cannot grow in the shade. It can grow in water.


Edible Uses
None known
Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Detergent;  Miscellany.

Used in the treatment of abscesses, boils and wounds, especially if there is debris in the wound[147]. A dried powder of the plant is applied to cuts and wounds to help accelerate healing[272].
Other Uses

The plant is used in sugar refinery[177]. No more details are given.
Cultivation details
A submerged water plant, it prefers growing in alkaline water[200]. A good oxygenator for ponds, the plant forms a large mass with stems up to 2 metres long[1, 200]. This is a very vigorous species which can regrow from even small sections of the plant. Stem fragments become rooted by fine, unbranched adventitious roots and soon produce vegetative reproductive structures from both subterranean and erect stems[270]. Tubers produced on subterranean stems are pale brown; those produced on erect stems are dark olive-green and covered with short, stiff scales. Both types germinate quickly to produce new stems[270]. This species has often invaded native habitats, clogging waterways and crowding out native species of flora and fauna[274]. It is considered a noxious weed in many areas[274]. Plants can be monoecious or dioecious. Dioecious plants (usually female) are triploid forms whilst monoecious plants are diploid[274]. Male flowers are released from the plant under water. They float to the surface where they release their pollen to fertilize female flowers[274].
Seed - it is quite likely that seed must be kept moist in order to maintain viability. If seed can be obtained, it is probably best sown immediately in a greenhouse in soil covered with water. Tubers - plant immediately in soil covered in water, Division - even small sections of stem will soon start producing roots when placed in water.

Books by Plants For A Future

Other Names
Found In
Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status
IUCN Red List of Threatened Plants Status :
Related Plants
Plant Suppliers: Click here for a List

      You can download this page as a PDF

Due to a fault in the PDF printer we are trying a few different options. Please try the one below


Print Friendly and PDF
Expert comment
Botanical References
Links / References
For a list of references used on this page please go here
Readers comment
Elizabeth H.
Phoebe Wilson Wed Jun 21 18:49:04 2000
I recently came upon your 'Plants for a Future' website at:


where there is erroneous information about Hydrilla verticillata. If you really believe the following information apparently supplied by 'Plants for a Future', made on that website:

Known Hazards: None known

then someone needs to do some more research before they provide information to other people. Just visit: http://aquat1.ifas.ufl.edu/prohib.html http://aquat1.ifas.ufl.edu/hydrinex.html to see the problems associated with Hydrilla verticillata.

Since you live in the UK, you probably have no way of knowing about these problems, but I assure you they are very real. That plant is considered an extreme pest, to the point where they are considering some kind of biocontrol. Here in Florida, we certainly would never encourage cultivation of such a plant.

I just thought you might like to update your information.

Elizabeth H.
sangeeta dhote Thu Aug 23 2007
Hydrilla verticillata can be used for water purification as it removes pollutants from water and waste water.
Elizabeth H.
Debra Pipkins Sun Feb 3 2008
can this plant affect creatinine levels in the kidney?
Elizabeth H.
deepank arya Wed Feb 13 2008
it is very beautiful for how those how like flowers.it is most use in study
Elizabeth H.
Mon Apr 13 2009
Elizabeth H.
Dr Manisha Acharya Tue Jan 12 2010
I need Hydrilla verticillata powder,please advise who can supply.
QR Code

What's this?

This is a QR code (short for Quick Response) which gives fast-track access to our website pages. QR Codes are barcodes that can be read by mobile phone (smartphone) cameras. This QR Code is unique to this page. All plant pages have their own unique code. For more information about QR Codes click here.

1. Copy and print the QR code to a plant label, poster, book, website, magazines, newspaper etc and even t-shirts.
2. Smartphone users scan the QR Code which automatically takes them to the webpage the QR Code came from.
3. Smartphone users quickly have information on a plant directly for the pfaf.org website on their phone.
Add a comment/link

If you have important information about this plant that may help other users please add a comment or link below. Only comments or links that are felt to be directly relevant to a plant will be included. If you think a comment/link or information contained on this page is inaccurate or misleading we would welcome your feedback at admin@pfaf.org. If you have questions about a plant please use the Forum on this website as we do not have the resources to answer questions ourselves.

* Please note: the comments by website users are not necessarily those held by PFAF and may give misleading or inaccurate information.

To leave a comment please Register or login here All comments need to be approved so will not appear immediately.

Subject : Hydrilla verticillata  

Plant Uses

Edible Uses
Medicinal Uses
Other Plant uses
Woodland Gardening
Why Perennial Plants?
Top Edible Plants
Top Medicinal Plants
Garden Design

Twiter      Facebook


Content Help
Support Us
Old Database Search
About Us
Sign In

PFAF Newsletter

Stay informed about PFAFs progress,
challenges and hopes by signing up for
our free email ePost. You will receive
a range of benefits including:
* Important announcements and news
* Exclusive content not on the website
* Updates on new information &
functionality of the website & database

We will not sell or share your email address.
You can unsubscribe at anytime.