I have lovely volunteer wild phlox growing in my garden where I don’t want them, but I have a perfect place where they would look wonderful. Can I transplant them, and if so, when is the best time to do it? Are there any tips that will increase my chances for success?
I’d suggest that you first make sure that the plants are really phlox; these are often confused with an invasive plant called dame’s rocket. Dame’s rocket has 4-petalled flowers and leaves that attach alternately. Phlox flowers have 5 petals and its leaves are opposite. If the plants are dame’s rocket, they have a shallow root system, so you can transplant them any time. If you transplant them while blooming, the flowers will likely die back, but return again next year. Keep an eye on your patch — if you find the plants spreading too much, just pull a few out by the roots. With phlox, as with most perennials, it’s usually best to transplant in the early spring (before its growth takes off ) or in the fall. However, most perennial roots survive transplants quite well. So go ahead and transplant them now, but again, they’ll lose this year’s blooms and likely be somewhat sad and limp after the transplant. Roots are the key to a successful transplant, so when you dig up the plants, include as many intact roots as possible. Ensure, too, that the new “home” is welcoming to the plant – if it’s happily growing where you don’t want it, perhaps it’s because of the type of soil, sun/wind exposure, etc. in that location. For example, woodland phlox species like blue phlox (which might be what you have) prefer moist, rich soil and full- to part sun. Don’t over-water, and don’t fertilize the plants after the transplant, as this stresses them. However, phlox are quite adaptable and may be happy in the new location you select.
Of course, to hedge your bets, you may not want to transplant all the plants at once. Keep a few where they are now (unless you have plans for that site!) so you can transplant again later this season, if need be.