The Right Place
Garden phlox thrive in direct sun. Any location receiving full sun to partial shade, which is better for the blue colored phlox, is satisfactory. They do best in a moist, well-drained soil high in organic matter. They dislike heavy clay. The soil should be neutral to slightly alkaline (pH 7.0 to 7.5).
Planting Nursery Stock
Purchase container grown plants at a reputable nursery or garden center. They can be put out in either the fall or early spring. Fall planting is best so that vigorous growth can get underway immediately in the spring and produce larger, showier blooms the first season. Choose an overcast day to plant to minimize transplant shock to the plant.
Work organic matter such as peat moss compost or chopped leaves down into the soil about 8 or 10 inches to improve its ability to hold water. Then dig a hole slightly wider than the plant container and just deep enough so that the phlox will sit at the same depth as it did in its container. Typically phlox roots are happiest at a relatively shallow depth. Set the plant in the hole, fill the remainder of the hole with plain soil, pressing it firmly around and over the roots. Water generously at planting time and for several days thereafter until new growth shows that the plant is established. Spread an mulch of some organic material such as chopped leaves over the root zone to help retain soil moisture and discourage weeds. Space plants at least 18 inches apart. They spread rapidly.
Amendments In Planting or Transplanting
There are a number of products at the garden center that will help your newly planted or transplanted plants deal better with the stress inherent in the planting process. All healthy plants have beneficial fungi, called mycorrhizal fungi, living on their roots. You can buy these valuable additions to your plant’s ecosystem. See the file describing Using Micorrhizae When Planting.
In addition, there are a number of products such as seaweed, compost tea, and beneficial soil microbes that when added to the planting process will help your newly established plants get going faster. See the file New Technology In Plant Growth Activators