You may have noticed a very tall and attractive pink flower in fields and roadsides that is starting to bloom now. Himalayan jewelweed (Impatiens glandulifera) is a highly invasive plant that has become very problematic in areas near Waldo County, where it has completely crowded out our native asters, goldenrods and other wetland and open area plants in some places. It can also impact production areas managed for hay fields, pasture and blueberries. Himalayan jewelweed is unusually tall for an annual plant, often reaching 5-7 feet in height. It is a prolific plant (each plant can produce about 800 seeds with high germination rates), enabling it to out-compete native vegetation. Its replacement of perennial vegetation on river banks may lead to increased soil erosion. Himalayan jewelweed is found in early successional forest, edge, floodplain forest, railroad right-of-way, roadsides, wet meadows, as well as gardens and yard, preferring moist sites. It is commonly found in riparian habitats (along streams). Himalayan jewelweed resembles our native jewelweed, which is orange flowered and not as tall.
The good news is, if you catch it early, it is relatively easy to manage. Pull gently on the plants and they generally come right out including the roots. Pulled plants should have dirt removed from roots and be placed on non- soil surfaces in the sun to dry out. Break off the flowers and bag them, closing the bag and leaving it in the sun for a while, then incinerate or dispose of the bag. The flowers can create their seed pods even if pulled. Ideally, pull the plants just as soon as you see them flowering, to avoid “popping” mature seed pods, which spread the seed by exploding. Cutting this plant or topping it will just cause it to quickly regrow new flowers. Plan to pull it the next year as well as new seeds sprout, but eventually you can eradicate it this way. Extensive stands can be managed with a foliar herbicide spray applied in July. There are many places in Waldo where this plant is just beginning to get a foothold, so pulling any you see on your land and talking to your neighbors about it may help us keep this plant at bay in our area.
If you enjoy having a tall, beautiful pink flower this time of year, a good substitute for Himalayan jewelweed is our native fireweed (Epilobium angustifolium), which can be planted from purchased seeds, and coastal joe pye weed (Eutrochium dubium), available from Wild Seed Project.