Japanese Knotweed Quiz How much do you know about this highly problematic plant? Take this quizz to see how you do! Knotweedcontrol.ie published on January 04, 2015 Stacked 1/7 Which of the two Knotweed plant species can produce a hybrid? Japanese Knotweed and Giant Knotweed Japanese Knotweed and Himalayan Knotweed Giant Knotweed and Hybrid Knotweed 2/7 In what year did Japanese Knotweed reach the shores of the UK? 1854 1860 1851 1850 1901 3/7 Which of the 3 Knotweed species is said to be most invasive and problematic to control? Hybrid knotweed (Fallopia japonicus x bohemica) Japanese knotweed (Fallopia japonica) Giant knotweed (Fallopia sachalinensis) 4/7 Which Knotweed species can spread by seed? Japanese Knotweed Hybrid Knotweed Giant Knotweed 5/7 There is growing evidence that Invasive plants like Knotweed species use biochemicals to inhibit the growth of roots in native plants. Any ideas? Type answer. Hint: 10 characters 6/7 When is the best time to treat Knotweed plants with herbicide? Hint: 2 choices After the knotweed has reached its maximum height, frommid-summer onwards, but before die-back at the first frosts. March to August August to March Optimum time of application is late season (Mid to late September). An early season spray maybe required in year 1 to assist with access for the late season ... 7/7 When a management plan is prepared for the control of Knotweed species near waterways, What is best practice in terms of chemical herbicide choice? Glyphosate(360 g/L) where product has an aquatic registration Triclopyr 240 g/L picloram, 120 g/L