Related by context. Frequent words. (Click for all words.) 56 Japanese knotweed 56 invasive weed 54 knotweed 53 water hyacinth 53 phragmites 53 invasive weeds 52 conifers 51 buckthorn 51 purple loosestrife 51 invasives 51 invasive species 51 invasive alien 50 garlic mustard 50 hardwood trees 50 tamarisk 49 salt cedar 49 hemlocks 49 junipers 48 conifer 48 waterbirds 48 knapweed 48 beech trees 47 insect pests 47 fungal disease 47 species 47 leafless 46 hydrilla 46 woody plants 46 spider mites 46 noxious weed 46 noxious weeds 46 lady beetles 45 pests 45 mangrove trees 45 nonnative 45 emerald ash borer 45 varroa mite 45 gray squirrels 45 bark beetle 44 Asian longhorned beetle 44 beetle infestation 44 stink bug 44 lodgepole pines 44 vegetation 44 grasses 44 wading birds 44 elms 44 weevil 44 elm trees 43 insects 43 mountain pine beetles 43 psyllid 43 beetle 43 fungus 43 ash borer 43 marsh grasses 43 viburnum 43 maples 43 lodgepole pine 43 ladybirds 42 insect pest 42 gypsy moths 42 milfoil 42 aphid 42 Emerald Ash Borer 42 trees 42 insect 42 weeds 42 hardwood forests 42 woodlands 42 gypsy moth 42 cheatgrass 42 mangrove forests 42 dogwoods 42 heathland 42 hedgerows 42 overwintering 42 armyworms 42 caterpillars 42 Invasive species 41 Dutch elm disease 41 beetles 41 dieback 41 aquatic vegetation 41 powdery mildew 41 citrus trees 41 borers 41 horse chestnut 41 Aphids 41 bark beetles 41 fungi 41 ash trees 41 elm 41 poplars 41 crape myrtles 41 ornamental trees 41 feral pigs 40 citrus greening 40 weevils 40 infestation 40 bird species