View Full Version : Hydrilla

02-07-2010, 02:31 PM
Common Name: hydrilla, water thyme.

Taxonomy: Family-Hydrocharitaceae (Frog's Bit Family); Order-Hydrocharitales; Subclass-Alismatidae; Class-Liliopsida (Monocots); Division-Magnoliophyta (Angiosperms).

Identification: Submersed perennial herb. Rooted, with long stems that branch at the surface (http://nas.er.usgs.gov/taxgroup/plants/images/hydrilla/hysub2.jpg) where growth becomes horizontal and dense mats form. Small, pointed leaves (http://nas.er.usgs.gov/taxgroup/plants/images/hydrilla/H_verticillata3.jpg) are arranged in whorls of 4 to 8. Leaves have serrated margins (http://nas.er.usgs.gov/taxgroup/plants/maps/hy_vert_bio.jpg) and one or more sharp teeth under the midrib (see Godfrey and Wooten 1979). Development of these features may vary with location, age, and water quality (Kay 1992).
Southern populations are predominantly dioecious female (http://nas.er.usgs.gov/taxgroup/plants/images/hydrilla/hydrilla_ready.JPG) (plants having only female flowers) that overwinter as perennials. Populations north of South Carolina are essentially monoecious (having both male and female flowers on the same plant) (Madiera et al. 2000; link to map of hydrilla biotypes (http://nas.er.usgs.gov/taxgroup/plants/maps/hy_vert_bio.jpg)). They set some fertile seed, and depend on tubers for overwintering.
Native Range: The common dioecious type originates from the Indian subcontinent. Historical reports specify the island of Sri Lanka (Schmitz et al. 1991) while random amplified polymorphic DNA (RAPD) analysis point to India's southern mainland (Madeira et al. 1997). Korea appears the likely origin for the monoecious type (Madeira et al. 1997).
Habitat: Freshwater lakes, ponds, rivers, impoundments and canals.


02-07-2010, 03:27 PM
they was more than one type of hydrilla in the potomac untill 2 years ago. expect to see it make a comeback before long

03-14-2012, 08:31 PM
Is that the same hydrilla that the property owners at lake gaston are always trying to get rid of?

04-03-2012, 12:44 PM
yep. bastages.

04-03-2012, 02:12 PM
I was reading my most recent Virginia Wildlife Magazine and they were talking about invasive species. Hydrilla is listed as one of them, and is currently listed in the Top-5 to be managed/eradicated and dealt with as it relates to money spent to control.

Particularly it was talking about one of the lakes out in western VA. Can't remember which one, but I'm pretty sure it was Claytor, where they are going to start with a fairly aggressive campaign with first carp, then spraying if needed.

The article specifically said that it chokes out fisheries and harms the fish habitat...that was news to me...???

Oh, and the snakehead was barely mentioned.

04-03-2012, 02:26 PM
for some reason VA has a major issue with grass in any lake, thank god they don't own the major portion of the Potomac. There is a reason that the best bass fishing lakes in the country are just that. GRASS. You name it its got grass. Look at possibly 3 of the Top 5 fisheries on the East Coast, they all have grass. Those would be Lake Champlain, Lake Guntersville and the Potomac River. They eradicate grass in any and all lakes that contain it. Claytor does have grass that holds a lot of fish in it during the warmer months. I bet that in 2-3 more years Briery Creek will be a shadow of its former self because they dumped 30k grass carp in their to remove the Milfoil and hydrilla.

As far as the Snakehead goes they've openly admitted that its a losing battle and they are hear to stay.

04-03-2012, 02:43 PM
yep, it was claytor. sumbeechees kilt all the grass already. the carp are starving. where's PETA when you need'em.

04-03-2012, 03:27 PM
There is a reason that the best bass fishing lakes in the country are just that. GRASS. You name it its got grass. Look at possibly 3 of the Top 5 fisheries on the East Coast, they all have grass. Those would be Lake Champlain, Lake Guntersville and the Potomac River.

LOL - that's exactly why their statement was news to me.

04-03-2012, 04:39 PM
I don't really understand the weak arguments they make readily available for public ears. It makes the lake access impossible for recreational boaters, LIE, it clogs the pipes to the power plant, LIE, its unhealthy for the fishery, LIE.

04-03-2012, 05:26 PM
The hydrilla on Anna years back was sweet and I caught more fish back then, not any real size but lake was also still young.
The hydrilla on the river years back was a lot thicker, use to see it harvested to put on farm lands for fertilizer. This also cleaned the water up tramendesly which is also vital to the bays cleaner water and its aquatic vegetation to help it's health.

04-03-2012, 05:28 PM
Grass carp can eat 10x there body weight daily and can reach weights of 100#'s, that's 1000#'s of grass a day for a grass carp at full size. Really I think you can take care of any grass problem with just one of them basteds

04-03-2012, 05:30 PM
The grass above looks like what I've seen on rapp?

potomac camo top
04-11-2012, 08:59 PM
Hadrilla > Milfoil in my upion

04-11-2012, 09:02 PM
what besides hay bales will kill hydrilla and slime in a pond?cheapest possible way please

04-12-2013, 03:27 AM
So what does this plant mean in terms of fishing? I know I've seen lots of pike hiding in this stuff and it's usually good fishing if you manage to keep your line clear of it.

04-12-2013, 05:39 PM
I think folks get all excited about any invasive non indigenous species taking over a body of water, because it may destroy the original plant life and upset the balance of life. I've heard many folks complain that the New River isn't the same from the Dam down to Whitethorne insofar as smallmouth fishing. They complain of numbers and of size and blame most of it on the abundance of grass since the River Course opened several years ago. I have also heard other theories which revolve around giant flatheads and musky eating all the bass. I also heard folks complain of finding worms in the meat of the smallmouth. They believe the worms are limiting the numbers, which i think is ridiculous. Those worms are in fish everywhere and people just cook them through or scrape em out. I tend to think the New just received too much pressure when its reputation started to overtake the James. Now the James is starting to produce citations in greater numbers. It could all just be cyclical.