Invasive Asiatic False Hawksbeard -- Part 2

It is now May and Asiatic False Hawksbeard is in the early to mid to stages of flowering in the Northern Virginia Piedmont. In a previous post, I discussed controlling invasive Hawksbeard in wilderness areas and cultivated spaces. Youngia japonica is also a significant pest of lawn turf and will be spread by mowers and weed trimmers when the plant is dropping seed. This plant can be controlled in lawn turf by hand pulling. When it is flowering, most plants come up easily when pulled at the base of the stalk. Pulled plants should be bagged in the later stages of development as they may continue to develop seeds. In the early stages of flowering, pulled plants may be left to dry and die but the stalks of larger individuals should be severed from the tap root as a precaution against the development of viable seeds. When invasive Hawksbeard is in the later stages of flowering, developing seeds and/or dropping seed, pulled plants should be bagged. 

A string trimmer may also be used to scalp Asiatic False Hawksbeard in lawn turf. The trimmer should be angled so that the cuts are made through the center of the rosette, obliterating the primary as well as secondary leaves. Another strategy is carefully timed repeated mowing first by raising the deck to make a primary cut and then monitoring the regrowth for a secondary cut, lowering the deck as needed for additional cuts until the plant’s resources are exhausted. Because invasive Hawksbeard is a biannual, carefully timed repeated top cuts is a viable control strategy. However, timing is very important! There is a risk that control efforts, particularly mowing and weed trimming, will aid in the spread of seeds to areas not previously infested. Hawksbeard seeds readily adhere to mower blades, string trimmers, clothes and shoes and may be carried and deposited into unaffected areas. Sometimes it is better to do nothing and control efforts should be abandoned when the plant is dropping seed if there is a high risk of spread to unaffected areas. 

Please email me with questions regarding this plant or the EDDMapS project at [email protected].

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