What is woodland phlox? It is a native plant that grows wild in the eastern areas of the country. However, increasing numbers of gardeners add woodland phlox plants to their gardens as ornamentals. If you would like to bring blue woodland phlox flowers into your garden, you’ll want to know how to grow woodland phlox. For information about woodland phlox flowers, and tips on how to grow them, read on.
I. Appearance and Characteristics
Phlox divaricata, the wild blue phlox, woodland phlox, or wild sweet william, is a species of flowering plant in the family Polemoniaceae, native to forests and fields in eastern North America.
The species name divaricata means “with a spreading and straggling habit”.
Wild blue phlox is a semi-evergreen perennial growing 25–50 cm (10–20 in) tall with opposite, unstalked, hairy leaves 2.5–5 cm (1–2 in) in length and ovate-lanceolate in shape. Flowers appear in late spring and early summer. They are pleasantly fragrant and 2–4 cm (3⁄4–1+1⁄2 in) in diameter, with five petals fused at the base into a thin tube. The petals are a variety of pastel colors: blue-lavender, light purple, pink, or white. Flowers bloom March to May. It grows in moist, deciduous woods and bluffs.
There are two subspecies: ssp. divaricata, with petals notched at the tip, and ssp. laphamii, without a notch.
Wild blue phlox is most common in the climax successional stage of a community. The flowers produce nectar at the base of the long, narrow corolla tube, and pollen near the end of the corolla tube. Only butterflies, moths, skippers, and long-tongued bees have long enough tongues to drink the nectar. Short-tongued bees and flower flies are unable to reach the nectar, but may gather or feed on pollen.
Phlox is self-incompatible, so it requires cross-pollination to produce seed. Butterflies are the most effective pollinators. As they insert their proboscis into the flower to drink nectar, it contacts the anthers and picks up pollen. As they coil the proboscis before moving to the next flower, most of the pollen falls off, but some remains to be transferred to the stigma of the next flower that they drink nectar from.
Cultivated varieties have various colours, including blue (‘Blue Moon’), lavender (‘Clouds of Perfume’) and white (‘Fuller’s White’, ‘White Perfume’).
Phlox divaricata and the lavender-flowered cultivar ‘Chattahoochee’ have both won the Royal Horticultural Society’s Award of Garden Merit.
II. How to Grow and Care
Sunlight
In a woodland garden, you can grow phlox as a potted plant or directly in the ground from partial to full shade. We do not recommend even growing them in full sun. Only the creeping phlox can take a bit more sun in the woodland phlox species.
With partial shade, you will get a display of blue to purple flowers filling up the garden.
Humidity and Temperature
The wild woodland phlox can handle high humidity but does not enjoy hot temperatures. For this reason, it is best to grow phlox in dappled shade in Eastern North America and other parts.
As long as your plants remain evenly moist, your plant will thrive. But, unfortunately, it is not heat tolerant. Another great thing is it can handle the winter well without much care, but it helps provide your phlox with mulch before it frosts to protect the roots.
Still, in very icy cold regions, you must grow your plant as an annual phlox or in a container to move it indoors in winter.
Watering
Keep the soil of woodland phlox evenly moist, but never waterlogged at all times. An application of landscape mulch will help retain moisture in the location that you have selected.
Soil
The care is remarkably the same whether you have a Phlox divaricata, Phlox paniculata, Phlox drummondii, or other species. So when you grow phlox, please provide them with the rich, loamy, moist potting mix that you find in woodland areas.
It is essential to provide them with well-drained soil for the best results. Still, the Phlox divaricata blue moon and other species are adaptable to grow in poor soil types like dry and clay soil when established plants.
Fertilizing
In the wild, your woodland phlox receives natural feeds from leaf litter that breaks down to form leaf mold. In the landscape, you can fertilize your plants with compost by working it into the ground annually in spring.
Pruning
You can cut back your plant after it flowers to give it a good appearance. The best time to do this is late summer to fall if you do not want them to reseed. Once the phlox stem flops to the ground, you will notice leafy shoots that start rooting.
Depending on the species, these roots can grow fast and readily spread to form a colony.
Propagation
You can propagate your plant in several ways, from division in early spring to fall or using stem cuttings to the seed.
Division
- Take a shovel with a sharp edge to detach sections of root cuttings where you want to divide your plant. The best is to take sections with enough roots attached.
- Next, dig around the divided section to lift it from the ground to prevent ripping the roots.
- Then, transplant those sections in a new location at the same depth as your mature plants. Water well and keep it moist until new growth appears.
Stem Cuttings Taken In Spring
- Take sharp, clean pruners to cut a section from the stem at the base of the parent plant. Choose a cutting with at least four sets of leaves and remove the lower ones.
- Take some rooting hormone, dip the cut end in it, and plant the cuttings in a pot with a moist potting medium. Leave the container outside in indirect sunlight.
- You should notice your plant rooting in about eight weeks and can check it by tugging gently on the stem. Then transplant your woodland phlox into the garden.
With root cuttings taken in early fall, you can handle them the same as your stem cuttings. You can plant them directly into the garden and keep it evenly moist.
How to Grow from Seed
The process is extended as the seed needs at least 60 days of cold stratification to help it germinate. You can do this outdoors or in the fridge. With natural stratification, you can sow the seed in late fall or winter in a weed-free location.
The cold weather is ideal for breaking the seeds out of dormancy, and you only need to wait for spring for them to emerge.
With artificial stratification, you can place the seeds on a damp paper towel, coffee filter, vermiculite, or sand in a sealed plastic bag. Then, store it in the refrigerator at 33° to 40° Fahrenheit.
The best is to use equal parts seed and sand to help keep it damp but not wet. Once you can work the ground in early spring, you can sow the seeds outside and care for them as usual. As the weather warms up, you will see your young plants emerging.
Overwintering
Prepare the plants for colder temperatures to ensure their survival. In regions where winters are mild, little to no special care may be needed beyond regular maintenance.
However, in areas with harsh winters, it’s advisable to mulch around the base of the plants to provide insulation and protect the roots from freezing temperatures.
Some gardeners opt to cut back the foliage in late fall to tidy up the garden and reduce the risk of disease or pest issues over the winter months.
Pests and Diseases
Woodland phlox is susceptible to spider mites1 and powdery mildew. As with any plant vulnerable to powdery mildew, aeration through appropriate spacing can help. It also helps to give woodland phlox a haircut after it has finished blooming since rampant growth can inhibit air circulation.
III. Types of Woodland Phlox
There are many other attractive types of phlox. Popular cultivars of woodland phlox and other phlox species include:
- P. divaricata ‘Blue Moon’, a cultivar with large violet-blue flowers.
- P. divaricata ‘Fuller’s White’, a cultivar with white flowers.
- P. stolonifera (Creeping phlox), a low-growing, mat-forming ground cover.
- P. subulata (Moss phlox), a creeping phlox that forms a carpet of color in the spring.
- P. paniculata (Garden phlox, tall phlox), panicles of blooms atop tall stalks in the summer.
IV. Uses and Benefits
Known for creating a cover of lilac flowers, wild blue phlox does best in woodland-like conditions. However, it is adaptable, also thriving in partially shaded beds and borders, naturalized areas, and rock gardens. Because it tolerates shade, it can be used as an underplanting of roses and other shrubs.
