my pond has bladderwort now for about 3 years. i've used diquat for contorling it but i was wondering why it's growing now and not before. maybe the ph in my lake has changed? is there a certain ph that bladderwort grows in?
Bladderworts are usually found in quiet shallow, acidic waters and can form dense mats. There is a possibility that your ponds pH could have been lowered due to a low alkalinity issue, but more than likely it just didn't grow before because it wasn't there. Have your water tested to determine pH, alkalinity, and if your water needs to be amended with lime, which it probably does if bladderwort is an issue. However, my best estimate of its recent problematic nature is that is was only introduced to your water 4 or 5 years ago. The Seeds are numerous and small as 0.2 mm to 1 mm long. These small seeds are easily trapped in the fur or feathers of small mammals and waterfowl which can transport them to new locations. Try fluridone or imazamox instead of diquat to gain longer term control and possibly eradicate the species from your pond. They are significantly more expensive, but are long lasting systemic herbicides that will prevent the need for frequent treatments annually with diquat.