Phlox paniculata, commonly known as creeping phlox, moss phlox, mountain phlox, moss pinks or thrift, is very easy to grow when planted right and in the right spot. Growing 2 to 5 inches tall and 24 inches wide, these delightful carpet-forming plants are ideal for use as a low edger or mass planting in landscape and perennial borders, home foundation plantings, on embankments, slopes or hillsides, or to slightly drape over stone walls. Its small size makes it a perfect fit for smaller garden spaces or as a soil cover in container gardens. A very nice addition to rock gardens. Flowering bulbs will pop right through it in spring and summer


Here's a breakdown of what you need to know for how to plant and grow Creeping Phlox like the pros...



Cultural Preferences



Soil Preferences

Creeping Phlox will grow in a variety of soils. It prefers a moist but well-drained soil however grows well in sandy or gravely soils and tolerates hot, dry exposures better than most other phlox species. As with so many other perennial plants, constantly soggy soils can be problematic. So make sure to plant in a well-draining site.


Testing Soil Drainage 

If you are uncertain about soil drainage in the area you intend to plant creeping phlox, it's well worth taking the time to test the drainage before planting. 

To test soil drainage, dig a hole 12" wide by 12" deep in the planting area. Fill the hole with water and let it drain. Then, after it drains, fill it with water again, but this time clock how long it takes to drain. In well-drained soil the water level will go down at a rate of about 1 inch an hour. A faster rate, such as in loose, sandy soil, may signal potentially dry site conditions and the need to add organic matter such as top soil to the native soil. A slower rate indicates poor draining soil and could be a caution you need to improve drainage or look for plants that are more tolerant of boggy conditions.


Soil Ph

Creeping phlox grows well in a moderately acid to slightly alkaline soil ranging from 6.0 to 8.0 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0. 


Testing Soil pH  

Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline. 

If you're unsure about the pH of your soil, or whether or not it is suitable for growing creeping phlox, it's a good idea to test the pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil SulfurAluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.




Light Preferences

Creeping phlox flower heaviest in full sun. That said, in the Deep South, plants will appreciate a little dappled shade during the summer.




How To Plant Creeping Phlox 

Scroll down for container planting instructions and care tips


Site Preparation For Mass Planting


Weed Elimination

Before planting, eliminate existing weeds or grasses in the planting area. You can pull weeds by hand or spray them with a solution of a broad-spectrum weed killer for use in landscape beds. Wait at least two hours after spraying a glyphosate-based product before you begin planting. Before using any chemical read and carefully follow the mixing and application instructions on the product label. 


Soil Preparation

Tilling the soil in the planting area is optional. There are a couple reasons I usually don't do it. 

Tilling on sloped ground loosens soil making it more susceptible to erosion in the event there comes heavy rainfall. 

Tilling can also bring buried dormant weeds seeds to the surface, and freshly tilled ground is a perfect environment for weed seeds to sprout. 

If you do decide to till, I suggest the application of a landscape weed preventer to the soil surface. 

Note:  If you are planting groundcover plants under established trees be aware that tilling can cause serious damage to tree roots , which could compromise health of a tree. Also note that the feeder roots of trees can often extend well beyond the perimeter of the canopy; up to 1 feet beyond the drip line (branch perimeter) for every 5 feet of tree height.


How Many Plants?

When mass planting creeping Phlox over a large area you'll first need to determine the total square feet of the planting area. Then you'll need to decided how far apart to space the plants in the planting area.

Suggested Spacing:  When mass planting Creeping Phlox, space plants 15 to 18 inches apart. The closer plants are spaced the quicker they will fill the planting area.


See:





Step-By-Step Planting Instructions

Note:  Creeping Phlox plants that have long, leggy runners can be clipped back by up to half their length to promote denser branching.


Step 1

Set and space all plants out in the planting area before starting to plant. Alternatively, you can use marking paint to mark the spot where each plant will go, which is often necessary when planting on steep embankments, hillsides or slopes, where plants in containers will not stay put. 

If there will be more than one row of plants in the planting area, begin by setting out or marking one row of plants. It's best to start with a row along the edge of the planting bed. Make sure to space plants at a distance far enough from the edge of the planting bed to allow for future spreading. For example, plants with a suggested spacing of 24" apart should be spaced at least 12" from the edge of the planting bed/area to the center of the plant. After setting out the first row, stagger the plants on the second row and so on until the space is filled.

Suggested Spacing:  When mass planting Creeping Phlox, space plants 15 to 18 inches apart. The closer plants are spaced the quicker they will fill the planting area.




Step 2

Start planting by using a shovel or trowel to dig your planting hole two to three times as wide and as deep or not much deeper than the root ball of your plant. Place native soil removed from planting hole around the perimeter of the hole, in a wheel barrow, or on a tarp.


Step 3

Depending on the type, fertility and porosity of the soil in the planting area, it may be beneficial to amend the native soil. When planting in heavy clay it is beneficial to thoroughly mix organic matter such as composted manure, bagged top soil, and or a good planting mix at a 50/50 ratio with the soil. When planting in a sandy, quick-draining soil amending with top soil, organic compost, or peat moss will help to retain moisture and supply vital plant nutrients. When planting in moist but well-drained soil of average fertility there is no need to amend soil.


Step 4

To remove your Creeping Phlox plant from the container it was growing in first squeeze the sides of the container to loosen the root ball. Then try to gently remove the plant from its container. If the root ball is stuck in the container use snips to cut the container away. After having removed the plant from the container, use your fingers to gently loosen some feeder roots around the surface of the root ball. 


Step 5

Set your plant in the planting hole so that the top edge of the root ball is at or slightly above ground level to allow for settling. It may be necessary to place some backfill soil mixture in the bottom of the hole to achieve proper planting height.




Step 6

After setting your plant in the planting hole, use one hand to hold the plant straight while using your other hand to begin backfilling the soil mixture around the root ball, tamping as you go to remove air pockets. When you have filled the hole to the halfway point you can soak the soil. Then continue backfilling to the top edge of the root ball. To avoid suffocating your plant, avoid placing any soil on top of the root ball.


Step 7

After planting some or all of your plants, deeply water the entire planting area. For an extra boost, you can water with a solution of Root Stimulator, which stimulates early root formation and stronger root development, promoting greener, more vigorous plants.


Step 8

Apply a 1" layer of shredded wood mulch or bark or pine straw around your plants. Avoid using freshly chipped or shredded wood for mulch until it has cured in a pile for at least 6 months, a year is better. 




How To Plant Creeping Phlox In A Container


Creeping Phlox plants are ideal for use as a soil cover and spiller in container gardens.

When growing in pots Creeping Phlox appreciate a moist but well-drained soil. Constantly soggy soil can and often will cause root rot or other harmful or deadly plant diseases. Therefore, plant in a container that has a drainage hole(s) and use a quality potting soil or potting mix, or a 50/50 combination thereof. You can add 10% pumice or Perlite to the soil mixture to enhance drainage.

Container color matters. Not only will you want to pick a color of container that goes well with the foliage and flower color of your Creeping Phlox, you'll also want to pick a container that matches the style of your home or other structures and other plants in the surrounding environment. 

Many nursery & garden centers offer a wide variety of containers to choose from. Before heading out to buy a container take pictures of your home and the surrounding environment. Doing so will help you to choose just the right color and style.


Container Planting Instructions


Step 1

Before filling your container with the soil mix, we recommend lining the bottom with shade cloth or a porous landscape fabric. This will keep the drain holes from becoming stopped up with soil. If you place gravel or rocks at the bottom of the container lay the fabric over it.


Step 2

To remove your Creeping Phlox plant from the container it was growing in first squeeze the sides of the container to loosen the root ball. Then try to gently remove the plant from its container. If the root ball is stuck in the container use snips to cut the container away. After having removed the plant from the container, use your fingers to gently loosen some feeder roots around the surface of the root ball. 


Step 3

Pour a small amount of your soil mixture in the bottom of the container. Set your plant(s) in the container and make necessary adjustments by adding or removing some soil so that the top edge of the root ball will sit 1/2 to 1" below the rim of the container.



Step 4

Backfill with your potting soil around root ball, tamping as you go, until the level of potting soil is even with the top edge of root ball.


Step 5

Water thoroughly until water starts to drain from the holes in the bottom of the container. Add more potting mix if settling occurs during watering.


Step 6 (Optional)

Apply a 1/2" layer of wood chips or sphagnum moss to soil surface to help conserve moisture.




How To Care For Creeping Phlox 

Feeding - Watering - Pruning

Caring for Creeping Phlox is very simple and easy. They are very low-maintenance plants.


How To Fertilize Creeping Phlox


In The Garden:  To encourage new growth and heavier flowering, Creeping Phlox plants growing in the ground will benefit from a feeding in late winter or early spring with a slow release flower fertilizer or organic plant food

In Containers:  Creeping Phlox growing in pots or other containers can be fertilized as directed on the product label in early spring and again in early summer with a slow release flower fertilizer or water soluble liquid plant food listed for use in containers.




How To Water Creeping Phlox

In The Garden:  Creeping Phlox plants growing in the ground prefer a consistently moist soil when young, however, are exceptionally drought tolerant when established. As with so many other plants, they do not like constantly soggy or wet soil, which can lead to root rot and other plant diseases. So be careful not to overwater!

In Containers:  Creeping Phlox plants growing in pots or other containers will appreciate a consistently damp to moist soil. Avoid overwatering to a point that soil stays constantly soggy. Allow soil to dry somewhat between waterings and then give the soil a good deep soaking until water runs out from the drainage hole.


After Planting

Immediately after planting deep soak the soil in the planting area to a depth of at least 6 inches. For an extra boost, you can also water with a solution of Root Stimulator, which stimulates early root formation and stronger root development, promoting greener, more vigorous plants.


During First Growing Season

In average garden soil you should not have to water your newly planted Creeping Phlox every day. More often than not, this causes soggy soil conditions that can lead to root rot and other plant diseases. In the absence of sufficient rainfall, water only as needed to keep the rootball and surrounding soil damp to moist. 

Keep in mind that deep soaking less frequently is much better than splashing just a little water on the plants every day. Plants planted during the winter dormant season, when not actively growing and evaporation is much slower, will require much less water. So, be extra careful not to overwater during winter!


Thereafter

When established, Creeping Phlox is quite drought tolerant. Provide supplemental water occasionally only during prolonged periods of dry weather.


Note:  When watering with an automated irrigation system it's best to set your timer to water during the early morning hours and not in the late evening or at night, which can lead to the onset of fungus and other foliar diseases. Check soil moisture within a few days after planting and adjust your irrigation system accordingly to provide only enough water to keep soil moist, but not soggy.




How To Prune Creeping Phlox


When provided sufficient space to grow Creeping Phlox does not require pruning or edging. If plants grow out of bounds they can be edged. 

Though not necessary, spent flower stems can be cut back or sheared to form a more dense carpet and possible rebloom.



Helpful Articles



Plant Long & Prosper

Questions? Contact Us