Phlox are herbaceous plants that bear a profusion of small, often scented flowers in summer. They range from tall border perennials to creeping or alpine varieties and woodland types, as well as annual varieties that can be grown as bedding.
Phlox paniculata is the most commonly grown garden phlox, often known as border phlox. In the wild, Phlox paniculata can grow to nearly 2m, and typically bears pink flowers. Years of breeding have resulted in shorter, more garden-worthy cultivars that flower in a variety of different colours, including shades of blue, purple, pink, magenta, red and white. As well as being fragrant and long-flowering, most cultivars attract a variety of bees and other pollinating insects.
Phlox are herbaceous border stalwarts – hardy and very easy to grow. They have sturdy stems, so even the taller varieties rarely need staking. Largely pest-free and disease-resistant, they last for years in the garden. They are excellent, low-maintenance plants for a herbaceous border or cottage garden and combine well with other herbaceous perennials such as delphiniums, campanulas and red hot pokers. For a more contemporary look, combine them with ornamental grasses. They make excellent cut flowers.
Most border phlox grow best in full sun, but as they are native to woodland edges they will also do well in partial shade.
Cultivars of creeping or alpine phlox, such as Phlox subulata, are low growing and flower in early summer. They thrive in full sun and well-drained soil. They make excellent ground cover and are often grown in a rockery. Varieties that hail from woodland habitats, sometimes called ‘woodland phlox’, such as Phlox divaricata, need partial shade and hummus-rich soil. Annual phlox, such as Phlox drummondii, are ideal as bedding plants or for growing in containers and are often grown from seed.
How to grow phlox
Most border phlox do well in a sunny spot in moist, well drained soil. They are sensitive to drought, so them keep well watered in hot, dry weather. They need little care, although deadheading promptly may result in more flowers later in the season, and dividing every few years will keep the plant healthy and flowering well. Alpine phlox need plenty of sun and well drained soil. Woodland phlox need shadier conditions.
Phlox: jump links
- Where to grow phlox
- How to care for phlox
- How to propagate phlox
- Phlox problem-solving
- Phlox buying advice
- Varieties of phlox to grow
Where to grow phlox
How to grow phlox – Phlox paniculata ‘Dusterlohe’
Grow your phlox in a sunny spot or in partial shade, in moist but well-drained soil. Taller varieties are suitable for the back or middle of a border, shorter varieties at the front.
How to plant phlox
How to grow phlox – phlox in a border
Plant phlox in spring or autumn, while the soil is warm and moist. Phlox don’t do well on dry, well drained soils, such as sandy soil, so improve with organic matter, such as garden compost or well-rotted manure, before planting and then mulch afterwards, too.
Where to buy phlox online
- Thompson & Morgan
- Van Meuwen
- Claire Austin
- Beth Chatto
How to care for phlox
How to grow phlox – doing the Chelsea Chop in late May
Phlox gradually form large clumps in the garden. To keep your plant growing well and to prevent it from becoming congested, divide it every three or four years, in early spring. Replant the clumps around 60cm apart. Signs that your phlox needs dividing are fewer flowers and a sparse centre.
If you’re gardening on poor soil, feed every spring with fertiliser.
Deadheading immediately after flowering might result in more flowers produced from side shoots in autumn.
Plants rarely need staking, but you may need to do this on a windy site.
If you want to stagger flowering or delay flowering, you can try the ‘Chelsea Chop’ on your plants. Cut some or all of the stems back by half in late May, around the traditional time of the RHS Chelsea Flower Show. Cut on the diagonal, just above a leaf joint. This will delay flowering by about a month.
Cut your plant down to ground level in autumn or winter, once the foliage has died back.
How to propagate phlox
You can increase your stock of phlox plants is by dividing them in early spring. Dig up the plant and split it into smaller chunks before replanting. These new plants will go on to flower in summer. Plant the new plants 60cm apart.
You can also propagate phlox by taking root cuttings in winter, before they start to send up their spring shoots. Use plants dug up from the garden or pot-grown plant. Place the pots of cuttings in a cold frame, where they’ll root and grow into new young plants by midsummer. They will then flower the following year.
How to grow phlox – selecting roots for root cuttings
Remove a few of the largest roots, as close to the base of the stem as possible, where’s there’s plenty of tissue ready to produce shoots.
How to grow phlox – root cuttings around 4cm long
Make the cuttings about 4cm long and take a nick out of the base (the end furthest from the root tip) so you know which way up they should be planted.
How to grow phlox – inserting root cuttings into compost
Insert the full lengths of root vertically into firmed compost, nicked end at the top, then cover with a good layer of grit and water in. Each cutting should produce a shoot in spring.
Growing phlox: problem solving
Phlox don’t like drought – you may notice the foliage wilting in dry weather. Your plant should perk up after it has been watered. In hot weather, water in the morning, making sure plenty of water reaches the roots.
Powdery mildew can be a problem in hot, humid weather, especially if your plant is growing in partial shade. If this tends to be a problem in your garden, improve air circulation by thinning the plants in early spring.
Advice for buying phlox
- Most phlox need moist but well drained soil and a sunny spot, so make sure you have the right conditions in your garden
- You can buy container-growin phlox all year round at garden centres and nurseries. You can also buy bare-root plants in winter – this is a cheaper option
- For the widest variety of plants, go to a specialist nursery or online supplier
Where to buy phlox online
- Thompson & Morgan
- Van Meuwen
- Claire Austin
- Beth Chatto
Varieties of phlox to grow
Phlox paniculata ‘Purple Eye Flame’
Pink and white Phlox paniculata ‘Purple Eye Flame’
Phlox paniculata ‘Purple Eye Flame’ has fragrant purple flowers with a white eye. It’s well suited to growing towards the front of a mixed or herbaceous border among daisies and echinaceas, or even in containers.
Phlox paniculata ‘Pina Colada’
White Phlox paniculata ‘Pina Colada’
Another perennial border phlox, Phlox paniculata ‘Pina Colada’ is a short-growing phlox, bearing large domed heads of pure white flowers. It’s perfect for growing in a night garden or near a seating area, where you can sit and enjoy its intense fragrance on summer evenings.
Phlox paniculata ‘Blue Paradise’
Purple-blue Phlox paniculata ‘Blue Paradise’
Phlox paniculata ‘Blue Paradise’ is a gorgeous border phlox, bearing fragrant, violet flowers with a faint paler patch and dark eye. Reaching heights of 120cm, it’s perfect for growing at the back of the border, where it works well with blooms of a similar colour.
Phlox divaricata subsp. laphamii ‘Chattahoochee’
Lilac-white Phlox divaricata ‘Chattahoochee’
This woodland phlox bears compact, spreading carpets of lilac-blue flowers in June, over fresh green, hairy leaves. It’s ideal for growing in large clumps at the edge of a border or beneath deciduous trees. The Royal Horticultural Society has given it its prestigious Award of Garden Merit.
Phlox drummondii ‘Moody Blues’
Purple-blue Phlox drummondii ‘Moody Blues’
Phlox drummondii ‘Moody Blues’ is an annual phlox that’s widely grown as a summer bedding plant. Its spreading habit makes it perfect for filling gaps at the front of a border, or forming part of a summer container display. It has a compact, bushy habit and bears flowers in a variety of shades of blue. Seeds are widely available.
- Buy Phlox drummondii ‘Moody Blues’seeds from Thompson & Morgan
Phlox subulata ‘McDaniels Cushion’
Pink Phlox subulata ‘McDaniels Cushion’
Moss phlox, Phlox subulata, is a spreading evergreen perennial growing to a height of just 15 cm. It bears small flowers in shades of pink, purple and white, from spring to early summer. Phlox ‘McDaniels Cushion’ forms a low, spreading carpet of slender, mid-green leaves and bears masses of pretty pink or purple flowers in summer.
When to Take Cuttings from Creeping Phlox
If you are a lover of this plant, it’s easy to propagate creeping phlox from cuttings. This is a nearly foolproof way to make more plants and add different colors to your collection for free. Creeping phlox sends out runners, rooting stems that are also a quick way to propagate the plant. Creeping phlox cuttings should be taken in either summer or fall, but seem to root best if planted in autumn. Some gardeners swear by taking them early in the season when they are actively growing, but the plants persist well into the cold season and rooted nodes will still sufficiently establish by the time full winter arrives. Cuttings of creeping phlox may be rooted stems which will more quickly establish or terminal end cuttings. The latter will need more time to send out roots but will do so provided they are cut near a growth node.
What You Need To Learn On How To Propagate Phlox Successfully
Propagating phlox from division
As mentioned earlier, propagating phlox from division is advantageous because it will not only provide you clones of your favorite species. But since phlox has multiple uses ranging from groundcover to hanging plants, you want to keep it neat as it matures. The stone that will hit these two birds is by dividing it into root cuttings.
The best time to divide phlox and take root cuttings is when the plant is just about to grow new shoots in early spring. You can dig around the plant to lift the cluster easier and sever the roots as you circle into the ground. Once you have the cluster, hose down the roots to remove the soil to make dividing easier.
You should spot the crowns at the top and use them as guides so that each section has enough roots and crowns to establish into a healthy plant. Some gardeners use their fingers to pull apart the divisions, but you can also use a knife. Make sure that you keep these divisions moist and plant as soon as possible.
When transplanting phlox, remember that they thrive well in fertile and moist soil. You can also choose somewhere bright and well-ventilated to encourage growth and avoid diseases like powdery mildew. More so, make sure that the location has good drainage and the hole is large enough to anticipate the size of the roots.
The spacing among plants can be five feet, but some gardeners allocate 10 inches depending on how you want the end positioning of plants will look. After you transplanted the plants, water them well but make sure that you don’t get the flowers and foliage wet when maintaining. A useful technique is a use of rooting fertilizer as your “water” to encourage faster establishment.
Types Of Phlox
Now that you know the best way how to propagate phlox, it’s worth learning the different types of phlox as well. This is a quick explanation of this plant’s general types, which you can use when modifying practices in the garden. However, do note that you still need to research your species to know if they have specific requirements and needs.
Annual vs perennial phlox
One of the most common types of phlox is an annual hybrid called the African Sunset Phlox. Other annuals are native to states like California, where they self-seed. Annual phlox plants usually thrive in full sun in fertile and moist soil with a pH of 4.5 to 7.0, but always check your species just to be sure of their needs.
On the contrary, perennial phlox plants usually offer various colors, not limited to shades of blue, red, white, and pink. There are also cultivars known for their fragrance, but gardeners often prefer perennial species because some are hardy and resistant to diseases like mildew. Depending on your location, you may find the appropriate perennial phlox that will thrive well in your conditions.
Creeping vs tall garden phlox
Some types of phlox that you might also encounter are the creeping and tall garden varieties. Perhaps you are already interested in the former because of the diverse colors it offers and the sweet smell it adds to the garden. More so, this groundcover plant works well in attracting pollinators.
On the other hand, the tall garden phlox is also colorful and fragrant. What’s fantastic with this phlox is that there are hybrids with contrasting colors for a unique addition to the garden. Because of their height, they make lovely additions in empty spaces.
It’s not easy to discover a species that offer different types ranging from tall flowers to groundcovers that also come in various colors. Therefore, knowing how to propagate phlox will always be a useful skill that you can use to maintain and create clones of your favorite varieties. The best way to propagate phlox is by division, and the process itself is straightforward.
You’ll just dig up the plant in early spring and hose down the roots to remove the soil. Make sure each section has enough crowns and roots to thrive and pull them apart. Then, plant these divisions in a fertile, moist, and well-draining location.
Overall, the emphasis is necessary on researching the phlox species you’re growing. Remember that there are many varieties and hybrids, so their growing requirements might vary. Nonetheless, this colorful and fragrant plant should be a stress-free addition to the garden.