Gooseneck Loosestrife

(Question)

What is the best method to eradicate Gooseneck Loosestrife from a perennial garden?

My garden is full sun, clay soil (not wet) and the Gooseneck loves it. I have tried digging it up, but it keeps popping up everywhere. My latest endeavor is to apply Roundup. I will see how that goes.

Barring Roundup and digging up everything up, is it also possible to plant perrennials that can coexist with the Gooseneck Loosestrife – I was thinking of Monarda and Joe Pyweed. Would they work? Is there another plant that could compete? If so, I will move everything else (coneflowers, phlox) to another bed.

Any other suggestions are welcome.

Thanks for your help

 

(Answer)

Although many gardeners still like and grow Gooseneck loosestrife, it can be invasive and very difficult to erradicate.  While Roundup (glyphosate) can be an effective way of getting rid of Gooseneck loosestrife, in Ontario Roundup cannot be used for cosmetic purposes.  There are a number of exceptions to the prohibition, including for health and safety reasons on plants which are poisonous to humans, but Gooseneck loosestrife does not fall within that category.  You should check the regulations where you are located before using.

Repeated digging out of the plants and roots can be an effective way of getting rid of Gooseneck loosestrife.  However, as the plant spreads by its underground rhizomes you must be very diligent to ensure that you get all of the roots and to remove any new shoots as you see them.  As you are already considering moving plants from the bed where the Gooseneck loosestrife is growing, I suggest proceeding with that plan, taking care to ensure that the soil around the roots of any plants that you are moving not contain have remanents of Gooseneck loosestrife roots.  You can then very carefully go through the empty bed trying to get all of the roots before replanting.

Gooseneck loosestrife thrives in moist soil and sunny conditions. As your bed is in full sun shade will be difficult to achieve but you can try and keep the bed dry.  For that reason when replanting the bed considering concentrating on plants which can themselve be aggressive and can tolerate drought-like conditions.  This should help contain any Gooseneck loosesrife roots or plants that remain.  These would include Joe Pye weeds (except some varieties such as fistulosum which perfer moist conditions) and Monardas as well as other plants such as solidagos (goldenrods), baptisa (false indigo), ratibida pinnata (grey-headed coneflower), agastache (giant hyssop), helianthus (sunflowers), some grasses (i.e. pannicum) and rudibeckias (coneflowers). You might should also consider installing a 12 to 18 inch barrier (such as is used to contain bamboo) around the perimter of this bed to prevent Gooseneck loosestrife from spreading to other areas of your garden.

Good luck.  With quite a bit of work, you should be able to develop a bed in which the Gooseneck loosestrife is either irraticated or contained.