Phlox is a charming and diverse genus of flowering plants belonging to the family Polemoniaceae, comprising around 67 species that are native almost exclusively to North America, with one species found in Siberia. They have been cultivated in gardens for centuries and remain among the most popular and widely grown flowering perennials available to gardeners today, valued for their prolific blooming, sweet fragrance, and wide color range.
The flowers of phlox are instantly recognizable — each bloom is made up of five flat, rounded petals arranged in a perfect star or pinwheel shape, often featuring a contrasting colored eye at the center. They appear in an extraordinary range of colors including white, pink, red, magenta, lavender, purple, and countless bicolor combinations, creating a bold and beautiful display that lights up gardens from spring through summer depending on the variety grown.
Phlox come in a wonderful variety of growth habits to suit different garden situations. Tall garden phlox (Phlox paniculata) grows up to four feet and produces large, fragrant flower clusters ideal for the back of borders. Creeping phlox (Phlox subulata) hugs the ground and spreads to form a dense, colorful carpet perfect for rock gardens and slopes, while woodland phlox (Phlox divaricata) thrives in shaded, naturalistic settings.
As garden plants, phlox are highly valued for their ability to attract pollinators. Their nectar-rich, fragrant flowers draw in butterflies, bees, and hummingbirds in impressive numbers, making them an essential component of any pollinator-friendly garden. The sweet, distinctive fragrance of tall garden phlox in full bloom on a warm summer evening is one of the most pleasurable sensory experiences a garden can offer.
Phlox are generally hardy, adaptable perennials that, once established, return reliably year after year with increasing vigor and spread. They prefer full sun to partial shade and well-drained, consistently moist soil enriched with organic matter. Regular division every three to four years keeps clumps vigorous, prevents overcrowding, and ensures the best possible flowering performance from established plants.
One of the most common challenges associated with growing phlox, particularly tall garden varieties, is powdery mildew — a fungal disease that coats leaves in a white, powdery film, especially in warm, humid conditions with poor airflow. Choosing mildew-resistant cultivars, spacing plants generously, watering at the base, and ensuring good air circulation around plants are the most effective strategies for keeping phlox healthy and looking their best throughout the growing season.
How to Grow Phlox From Cuttings
- Understand Why Cuttings Are Valuable — Growing phlox from cuttings is one of the most reliable and rewarding methods of propagation because, unlike seed-grown plants, cuttings produce new plants that are genetically identical to the parent. This means the new plants will have exactly the same flower color, fragrance, growth habit, and other desirable characteristics as the original plant you selected.
- Choose the Right Time for Taking Cuttings — The best time to take phlox cuttings depends on the type of cutting you are taking. Softwood cuttings are taken in spring when new growth is young and soft. Basal cuttings are taken in early spring as new shoots emerge from the base of the plant. Semi-ripe cuttings can be taken in midsummer when stems have begun to firm up slightly but are not yet fully woody.
- Select the Best Parent Plant — Always take cuttings from the healthiest, most vigorous, and most floriferous plants in your garden. Avoid taking cuttings from plants showing signs of disease, pest damage, or stress, as these problems can be carried over into the new plants. A strong, healthy parent plant gives your cuttings the best possible start in life.
- Prepare Your Tools Carefully — Before taking any cuttings, ensure your cutting tools are scrupulously clean and sharp. Use a clean, sharp knife or pair of scissors that have been wiped with rubbing alcohol or dipped in a diluted bleach solution. Clean, sharp tools make precise cuts that heal quickly and significantly reduce the risk of introducing disease into the cutting.
- Take Softwood Cuttings Correctly — For softwood cuttings in spring, select healthy, non-flowering shoot tips that are about 3–4 inches long. Cut just below a leaf node using your clean, sharp knife or scissors. Remove all leaves from the lower half of the cutting, leaving only two or three pairs of healthy leaves at the top to support the cutting while it roots.
- Take Basal Cuttings in Early Spring — Basal cuttings are taken by carefully cutting young shoots from the very base of the plant as they emerge from the ground in early spring, when they are about 3–4 inches tall. These shoots are particularly vigorous and root very readily, making them arguably the most reliable type of phlox cutting for successful propagation results.
- Use Rooting Hormone — Dip the cut end of each prepared cutting into rooting hormone powder or gel before inserting it into the rooting medium. Rooting hormone contains auxins that stimulate root cell development and significantly improve both the speed and success rate of rooting. Tap off any excess powder gently to avoid applying too thick a coating around the cut stem.
- Prepare the Rooting Medium — Fill small pots or a seed tray with a free-draining rooting medium such as a mixture of equal parts perlite and multipurpose compost, or a dedicated cutting compost. Avoid using ordinary garden soil or rich potting compost, as these retain too much moisture and can cause the base of cuttings to rot before roots have a chance to develop.
- Insert Cuttings Into the Medium — Make a small hole in the rooting medium with a pencil or dibber before inserting each cutting to avoid wiping off the rooting hormone as you push the cutting in. Insert each cutting to about one-third of its length, firming the medium gently around the base of the stem to ensure good contact between the cutting and the rooting medium.
- Create a Humid Environment — Cover pots or trays of cuttings with a clear plastic bag, plastic dome, or propagator lid to create a warm, humid environment that reduces moisture loss through the leaves while roots are developing. Ensure the plastic does not touch the leaves of the cuttings, as contact can cause rotting. Ventilate briefly each day to prevent excessive condensation building up.
- Provide the Right Conditions — Place cuttings in a warm location with bright, indirect light, ideally maintaining temperatures of around 60–70°F (15–21°C). Avoid placing cuttings in direct sunlight, which can scorch the leaves and dry out the rooting medium too quickly. A north or east-facing windowsill or a position in a shaded greenhouse or cold frame works very well.
- Monitor and Water Carefully — Check cuttings regularly and water sparingly only when the rooting medium begins to feel dry. Overwatering is one of the most common causes of cutting failure, leading to stem rot at the base. The medium should be evenly moist but never wet or soggy. Remove any cuttings that show signs of rotting or disease immediately to prevent problems from spreading.
- Check for Rooting — After about four to six weeks, check whether cuttings have rooted by gently tugging each one. Resistance to the tug indicates that roots have formed and anchored the cutting into the medium. Alternatively, look for new leaf growth at the top of the cutting, which is usually a reliable sign that roots have successfully developed below the surface.
- Pot Up Rooted Cuttings — Once cuttings have rooted successfully, carefully remove them from the rooting medium and pot them up individually into small pots filled with good quality potting compost. Handle the young, fragile roots as gently as possible during this process. Place newly potted cuttings in a sheltered, bright position and water them in well to help them settle into their new containers.
- Harden Off and Plant Out — Before planting rooted cuttings outdoors permanently, harden them off gradually over a period of one to two weeks by placing them outside in a sheltered spot for increasing lengths of time each day. Once fully acclimatized to outdoor conditions, plant them in their final position in well-prepared, fertile soil, spacing tall varieties 18–24 inches apart to allow good airflow and room for mature growth.