Care-free perennials for spring: woodland phlox

Blooming in concert with daffodils, tulips and other spring-flowering bulbs, woodland phlox grow into casual colonies, covering the ground and lighting up the shade with their white, blue, pink and lavender blossoms. These easy-care native plants add a dash of colour low to the ground in the springtime garden. [Image credit: iStock.com/NADEJDA2015]

The shady slopes of eastern North American woodlands harbour many native plants, including dainty spring-blooming phlox. Similar to tall garden phlox only in the size and form of its individual blossoms, woodland phlox are small plants that never surpass 30 centimetres (12 inches) in height.

• They grow into casual colonies, covering the ground and lighting up the shade with their white, blue, pink and lavender blossoms.
• Some selections are fragrant, and all reappear each year with no assistance from gardeners who grow them.
• Blooming begins in concert with daffodils, tulips and other spring-flowering bulbs, and the plants disappear by late spring.
• In sites that become deeply shaded after trees leaf out, hardy ferns make particularly good companions, hiding the thin, fading foliage of the phlox.

Along with its versatility, what makes woodland phlox appreciated by gardeners is the colourful carpet of flowers it forms if permitted to flourish naturally.

Favoured choices
Several native species fall into the woodland phlox category, but the most widely planted colour is the blue phlox (Phlox divaricat), a common choice for open glens framed by tall shade trees, good to Zone 4.

• Moss phlox (P. subulat) is a related species with ground-hugging, mossy foliage. This petite plant is typically grown on sunny slopes and completely covers itself with pink, white or lavender blossoms in early spring.

In filtered shade
Grow P. divaricat 'Clouds of Perfume', which forms 30-centimetre tall (12-inch) plants covered with fragrant blue blossoms, or 'Chattahoochee', which has violet-blue flowers with magenta eyes.

Where sunlight is limited
Try 15-centimetre tall (six-inch) 'Fuller's White' or 'Sherwood Purple' varieties or mix them together for an eye-popping duet.

For sunnier areas
Where there's more sun P. subulat 'Candy Stripe' is remarkable for its pink-and-white flowers with perky magenta markings in the centre of each little flower.

To start, set out plants in fall or spring in any soil that is well drained and has a neutral to slightly acidic pH.

• Amend sand or heavy clay with organic matter before planting and water well when plants are in place.
• The shade-tolerant species usually face little competition from weeds, but you will probably need to pluck out invaders from new plantings of moss phlox.
• After woodland phlox blooms in spring, let it shed seeds before clipping it back in midsummer.
• To save work you can cut down a large planting with the lawn mower, raising the blade to its highest setting to protect basal growth. Leave the area undisturbed and new growth will appear beginning in the fall, ready to bloom next spring.

Moss phlox needs no special care beyond fertilizing in early summer and occasional watering in severe droughts. It is less prone to insects and the fungal disease, powdery mildew, than its cousin, garden phlox.

Attributes
Plants are petite with blue, white or pink flowers. They're perfect for flower beds, ground cover and edging.

Season of interest
Spring is when they bloom.

Favourite varieties
Among the more popular phlox varieties are P. divaricat 'Clouds of Perfume' and 'Chattahoochee' for partial shade; 'Fuller's White' and 'Sherwood Purple' for shade, and P. subulat 'Candy Stripe' for sun.

Quirks
Prefers slightly acidic soil.

Good neighbours
Woodland phlox grow well alongside Candytuft, deciduous trees, pansies, spring bulbs and shrubs.

Where it grows best
Humus-rich soil in open woodlands, although it adapts well to rock gardens and more formal gardens if soil conditions are right.

Potential problems
Rare. This is a hardy plant.

Renewing plants
Woodland phlox lives for many years. Renewing is seldom needed if plants are allowed to reseed naturally.

Critter resistance
Good. Few pests bother this plant.

Source
When purchasing at a garden centre, woodland phlox is sold as bedding plants. You can also divide existing plants.

Dimensions
These are low-to-the-ground flowers. At their tallest – and widest – they attain only 15 to 30 centimetres (six to 12 inches).