Unwanted Kelp

Asked May 21, 2015, 5:44 PM EDT

I am looking for an effective way to eliminate a kelp like growth that is invading our park. I live along the Siuslaw River approximately 5 miles upriver from Florence. This kelp like growth first appeared after the flood conditions of 2011. I have tryed Crossbow, Roundup and a 50/50 mixture of chlorex and water. The kelp appears to continue to spread and grow. When dry after several days of sun, the growth is brittle. As soon as it rains the growth takes on the seaweed or kelp appearence. What is available to kill this kelp?

Lane County Oregon

2 Responses

Thanks for reporting this organism and sharing your concern. I would be glad to assist you. The first thing I need to know the name and location of the park. Is this park influenced only by fresh water or does seawater extend to where you are?

Can you provide me with two additional photos? One close up and another showing where it grows.

What are some of your concerns about the growth of this organism.

Also free to contact me by phone 5036794828. I am available after 1 PM on Wednesday, May 27th.

I just wanted to offer that the algae (actually a cyanobacteria) that you are seeing could be Nostoc. I didn't quite get from your description - is this growing in infields? The grass? Nostoc is a major issue in nursery container operations as well as on sports infields. It fits your description of drying up and then resuming it's regular growth after rehydrating.
Below is a link to information about control of this organism.