Perennial Solutions: Phlox divaricata ‘Parksville Beach’
Phlox divaricata produces a show-stopping display of color in the late spring, brightening up any landscape. Tony Avent from Plant Delights recently discovered a new cultivar, ‘Parksville Beach’, in the mountains of Parksville Beach, Tenn. This variety has many great attributes that are appealing for growers and landscapers alike.
‘Parksville Beach’ is a vigorous, but low growing, evergreen phlox that only reaches 4 to 6 inches tall when not in bloom and 8 to 10 inches tall when in flower. It produces an abundance of bright purple-pink fragrant flowers in mid to late spring. These evergreen plants are easy to grow and spread freely, reaching 2 feet across after several years in the landscape.
Woodland Phlox performs well across a wide portion of the United States, throughout USDA Hardiness Zones 4 to 8. ‘Parksville Beach’ prefers to be grown under bright shade in locations with rich, moist, well drained soils. It can be used to naturalize areas, in wildflower gardens, as a border planting, ground cover, in mass plantings, or used for container plantings. It also attracts hummingbirds and butterflies into the garden and is also considered to be deer resistant.
With its compact size, evergreen foliage, early bloom time, flower power and ease of production, ‘Parksville Beach’ would make a great addition to most perennial programs.
Phlox ‘Parksville Beach’ is vegetatively propagated from tip cuttings. Before sticking the unrooted cuttings (URCs), moisten the rooting medium in the liner flat. Place the cuttings under a low misting regime for about the first seven to 10 days of propagation. When possible, it is usually best to propagate under high humidity levels (90 percent relative humidity) with minimal misting. At seven to 10 days after sticking, it is beneficial to apply water soluble fertilizers using 75- to 100-ppm nitrogen at each irrigation beginning. The misting can gradually be reduced as the cuttings develop callus and begin to root. Remove the cuttings from the mist once they are rooted. The cuttings are usually rooted in less than three weeks with soil temperatures ranging from 64 to 68° F. Liners take approximately five to six weeks from sticking to become fully rooted and ready for transplanting.
Phlox divaricata are well suited for production in quart or 1-gallon containers. Woodland Phlox are typically planted during the late summer of the year prior to the intended market date. Planting phlox in the late summer allows them to bulk up, increases plant vigor, produces more flowers per plant, and results in earlier and more uniform flowering. Growers can also plant large vernalized liners into smaller container sizes in the spring for sales during the same growing season.
‘Parksville Beach’ performs best in well-drained growing mixes. When transplanting, the liners should be planted so the original soil line of the plug is even with the surface of the growing medium of the new container. It is beneficial to soft pinch the plants during the bulking phase to promote lateral branching and improve fullness and overall plant quality.
Woodland Phlox perform best at light to moderate fertility levels. Nutrients are commonly delivered using water-soluble sources, providing 75- to 100-ppm using a constant liquid fertilizer program or 150- to 200-ppm as needed. Controlled-release fertilizers can be applied as a top-dress onto the media surface using the medium labeled rate, or incorporated into the growing mix prior to planting at a rate equivalent to 1.0 pounds of elemental nitrogen per yard of growing medium. During production, phlox should be grown with a slightly acidic pH: 5.8 to 6.2.
Grow phlox under ‘average’ irrigation regimes. It is best to keep them uniformly moist, but not consistently wet. When irrigation is needed, water thoroughly and allow the medium to dry slightly between waterings.
With its compact growth habit, it is usually not necessary to implement height management strategies. If some growth control is necessary, the plants can be toned using spray applications tank combination of 2,000-ppm daminozide (B-Nine or Dazide) plus 3-ppm uniconazole (Concise or Sumagic).
Insects and Diseases
There are several pests and diseases that attack Woodland Phlox. Aphids, spider mites, thrips and whiteflies are the most prevalent pests; however, caterpillars, foliar nematodes, grasshoppers, leafhoppers and slugs may be observed feeding on them on occasion. The primary diseases which infect phlox are Botrytis, Cercospora leaf spot, Colletotrichum, Fusarium, Pythium and powdery mildew. Insects and diseases can be detected with routine crop monitoring; control strategies may not be necessary unless the scouting activities indicate actions should be taken.
Phlox ‘Parksville Beach’ is typically grown and sold in flower in early to mid spring. To produce the fullest containers with the most bloom it is best to bulk Woodland Phlox in the final container prior to overwintering. The amount of time required for bulking varies widely by the container size being produced. Provide a minimum of four weeks for quart-sized containers and up to eight weeks for one gallon pots. Prior to overwintering, allow at least four weeks from the time the plants are pinched until they are consistently exposed to temperatures below 50° F.
Phlox divaricata has an obligate cold requirement for flowering. They can be vernalized in the final container or as large plugs (72-cell or larger) for a minimum of six to eight weeks at 35 to 44° F. Following the cold treatment, they will flower under any photoperiod (day neutral plants) and can be forced into bloom under natural day lengths. The length of the photoperiod does not have any effect on the time to flower or the number of blooms produced.
There are two common approaches to producing flowering containers of Woodland Phlox. The first method described above entails planting unvernalized liners into the final container during early to mid fall, bulking them up, vernalizing them and forcing them to bloom in the early spring. The second strategy involves transplanting vernalized plugs into the final containers during the late winter and forcing them to flower in the mid spring. In either case, they can be grown using low production temperatures (60 to 65° F) and natural day lengths. When grown under these growing conditions, they will flower in approximately six to eight weeks.
Liners of Phlox divaricata ‘Parksville Beach’ are available from a limited number of propagators at this time. Current suppliers include Plant Delights Nursery, Inc. (www.plantdelights.com), Creek Hill Nursery (www.creekhillnursery.com) and North Creek Nurseries (www.northcreeknurseries.com).