Once you have identified the aquatic plant species, knowledge of its reproductive mechanisms will also assist with determining the best management technique.
Not all aquatic plants produce viable seed but spread and multiply from fragments of stem, root or leaves. Examples include salvinia and alligator weed. Other aquatic weeds produce seed and are also able to propagate from stem, root or leaf fragments. Examples include water hyacinth and water lettuce.
When planning a weed management program for aquatics weeds, managers must decide what is possible or necessary. For aquatic weeds that reproduce by fragments, every piece of plant material must be removed. This requires intensive follow up control until there is no presence of the weed at all. For plants that produce seed, control must be carried out until the soil seed bank is exhausted (this may take many years). In some situations some level of weed presence can be tolerated and management should consist of controlling priority areas or keeping the presence of the weed at suppressed levels.