Monday, May 16, 2011

Phlox Subulata--Creeping Phlox

Hello again,

Good gardening friend Paul Parent of the Paul Parent Garden Club sends out a great newsletter every week with pertinent gardening topics. I encourage you to go to his website to sign up for his newsletter. Paul can also be heard every Sunday morning from 6 AM to 10 AM at his website or at WBACH (104.7 FM) every Sunday morning from 6 AM to 9 AM. Paul recently sent this article out called "Phlox Subluta" (I occasionally add a few comments in italics) and here it is:

"Back in the days when this country was considered "The Colonies," our gardeners exported phlox plants to Great Britain. That's right, North America is the home to the entire phlox family of plants. Of the 70 species of phlox available, all but one is native. The botanical name for phlox in Greek means "flame," because the plants grew flowers in bright hot-looking colors. If you were a botanist, you would call the flower that the phlox makes a "salverform" bloom. A simple definition of "salverform" is a tiny tube-like flower that opens into a trumpet-shaped flared or flattened face with five petals. Most species produce these flowers in clusters that are rounded and believe it or not, even the ground phlox produces flowers in this rounded flower cluster. Next time you're out in your garden, lift up a side shoot from your clump and look closely at the flowers. What looks to be a carpet of single flowers is really small clusters of flowers covering the plant--check it out.

Various Colors of Ground or Creeping Phlox

When most gardeners think of phlox they think of the tall-growing phlox with beautiful ice-cream cone shaped flower clusters. They think of the warm summer nights with cool colors of lavender-blue, purple, mauve, pink red and white flowers standing up tall your garden. Summer-flowering phlox is nice, but to me the ground covering varieties are more exciting, because at this time of the year color in the perennial garden is still very limited. Most perennials are still dormant or just beginning to poke through the soil, but this wonderful plant is in full bloom. Not only that, but the perennial ground phlox is evergreen to semi-evergreen, and on those cold winter days when snow is not covering the ground the phlox is greener than your lawn. The ground phlox will tolerate temperatures down to -40 to -50 degrees--how many of your perennial flowers can tolerate that and stay green all winter long? Not many!

Ground phlox grow like a carpet, hugging the ground. They are creepers, covering even rocks in your garden and creating a mat of foliage that will cascade or trail over a short wall. Ground phlox will grow on or over any surface as well as obstacles; truly a unique flowering plant. During April we all crave color and the weather can still be cold and unsettled, but this plant does develop flowers that will stay in bloom on the plant even if the temperatures dip below freezing. For this to happen, your plant must have good drainage; otherwise it will suffer from root rot during cold, wet weather. The roots of the ground phlox grow don't grow very deep in the garden. If your soil is on the sandy side you may have to water during the summer months if the plant is growing in full sun or the summer is hot and dry.

Ground phlox will flower for 2 to 3 weeks during April or early May. In a more northerly growing area the spring time temperatures always determine the flowering time. When plants finish flowering, shear back the plant to help control the size of the plant and encourage it to stay full and thick. As the plant ages, it will begin to die out in the center; that is normal. Dig it up, divide the plant into sections, and remove the dead sections from the clump. Plant the outer edges as clumps, with fresh soil that you have conditioned with compost or animal manure. If you can add mycorrhizae when planting, it will help stimulate the new roots to form more quickly and the summer weather will help new growth to develop.

Ground phlox flowers come in shades of white, pink, purple, red, lavender-blue and a new hybrid pink and white striped variety called "Candy Stripe.' This plant can spread 2 to 3 feet wide and will grow to 6 to 9 inches tall. When the flowers fall the Kelly green foliage will begin to grow, it can spread 6 inches or more each summer. When you plant a young plant, the foliage will feel soft and smooth but as the plant ages, the foliage gets prickly and becomes needle-like, almost like a spruce tree. The once soft and flexible green stems will also get woody, turn brown, rough, and more rigid. This is your signal to divide the plant into small clumps 6 to 8 inches in diameter.

A soil that is slightly acidic to alkaline will work well to encourage new growth and many flowers. If your garden is near oaks and pines, I would suggest that you apply lime, wood ash, or Jonathan Green Mag-I-Cal every year to keep acidity levels down. Fertilize in the spring when the flowers begin to fade with a good perennial fertilizer such as Flower-Tone. (Or if your phlox are part of your lawn area like mine twice yearly lawn feedings with a good all around organic fertilizer will keep the phlox well fed.)
If you plant ground phlox in the front of your border, it will creep out into your lawn if not pruned after flowering. Grass will also grow into your flower bed from the edge and can create a problem if you do not edge the perennial bed every year. If the grass gets into the plant bed it may be necessary to dig it up and manually pull the grass and its roots from the clump. It is best to set plants 12 inches from the edge of the bed to prevent problems.

If you have a steep bank that is difficult to mow and you're looking for a ground cover, the ground phlox could be the right plant for you. Space plants on 18 inch centers in staggered rows and in a couple of years it will all grow together, creating a wonderful flowering hillside in the spring. When the flowers fade use the lawn mower to cut back the plants to keep them short and thick growing. Fertilize over the top of the foliage with organic fertilizer when rain is in the forecast or use your sprinkler to wash the food off the foliage into the ground.

Insects and disease problems are minimal, but if you see the foliage begin to bleach out a bit, it could be red spider mites. If this occurs spray the foliage with Tree and Shrub Systemic Insecticide to control the problem. The ground phlox does not get powdery mildew like the taller growing summer-flowering phlox does. Powdery mildew is the most destructive disease of the taller growing relative and many people do not grow phlox because of it. New resistant varieties are now available and better systemic fungicides are also available. If you want spring color that will brighten up your gardens at this time of the year there is no better plant than the ground phlox. Enjoy!"

Thanks Paul!

Mike Skillin
Skillin's Greenhouses
May 16, 2011

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