How to Grow Phlox
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Phlox has quickly become one of my favorite plants.
There’s just something so beautiful about their star-shaped flowers, whether they’re spreading across the ground, lighting up a garden border, or spilling out of a container.
There are several varieties of phlox—some grown for their height, others for their stunning spring carpets.
These plants are versatile, relatively low-maintenance, and offer blooms that last for weeks.
I’ve pulled together everything I’ve learned about growing and caring for phlox here.
From choosing the right type to propagation tips, I hope this guide helps you enjoy these flowers as much as I do.
For more growing tips, check out my guides:
Garden Phlox (Phlox Panicuata)
Choosing the Right Phlox for Your Garden
Picking the right phlox for your garden is like finding the perfect pair of shoes—it depends on the occasion, the fit, and what you want it to do.
With so many types of phlox to choose from, it helps to start with what your garden needs.
Garden Phlox (Phlox paniculata):
This one has a special place in my heart and my garden.
My mom and I planted it in my garden together, making it extra special.
There’s just something about those tall, elegant stems topped with clusters of star-shaped flowers that feels so classic and timeless.
One of the reasons I love garden phlox is how much presence it has.
Standing anywhere from 2 to 4 feet tall, it’s a real showstopper, especially when it’s in full bloom during the summer months.
The flowers come in several different colors—pinks, purples, whites, and even shades of blue—that it’s easy to find one that fits your garden design.
And the fragrance? Subtle, sweet, and the kind that makes you want to linger outside just a little longer.
Garden phlox thrives in full sun, but it’s forgiving enough to handle a bit of partial shade, which is great if your garden has a mix of light conditions.
It’s perfect for flower beds where you want height and drama, but I’ve also seen it tucked it into cottage-style gardens where it blends beautifully with other summer bloomers.
Caring for garden phlox is straightforward, but one thing I’ve learned is to give it some space.
Good air circulation is key to keeping it healthy and free from powdery mildew.
A little fertilizer in spring, some regular watering, and occasional deadheading keep it blooming strong all season long.
If you’re looking for a plant that adds elegance, color, and a bit of charm to your garden, I can’t recommend Phlox paniculata enough.
Creeping Phlox (Phlox subulata):
Look for ground cover or adding a splash of color to a rock garden?
Creeping phlox spreads out like a soft carpet, bursting with blooms in early spring.
It’s great for filling in spaces and adding texture without much fuss.
Annual Phlox (Phlox drummondii):
For instant gratification, annual phlox delivers.
It’s a one-season wonder that’s perfect if you’re itching to add quick color to beds or containers without waiting for perennials to establish.
Take a stroll around your garden, think about where phlox could fit in, and then match the variety to the vibe you’re going for.
It’s all about making it work for your space.
Woodland Phlox (Phlox divaricata):
If you’ve got a shady spot that could use some love, woodland phlox is the answer.
It is a wildflower that thrives in dappled light, giving you delicate spring blooms that feel almost magical.
For more wildflower growing ideas, check out my guide: The Best Wildflowers for Shade.
For more growing ideas, check out my guides:
Planting Phlox: The Basics
Planting phlox is straightforward, but getting the details right can make a big difference in how well it thrives.
Here are a few tricks to help phlox settle in happily and put on its best show.
1. When to Plant
Timing is everything.
For perennial phlox varieties like garden phlox and creeping phlox, planting in spring or fall works best.
Spring gives the plants time to establish before the summer heat, while fall planting lets them settle in before winter.
If you’re working with annual phlox, plant after the last frost for the best start.
2. Choosing the Perfect Spot
This step is where you can set your phlox up for success.
Full Sun or Partial Shade:
Most phlox varieties love full sun.
Think 6+ hours of sunlight daily for those tall garden phlox blooms.
But if you’ve got a shadier spot, woodland phlox will feel right at home.
Well-Drained Soil:
This is one thing I never skimp on.
Phlox doesn’t like “wet feet,” so if your soil holds too much water, consider adding compost or planting on a slight mound for better drainage.
3. Planting Tips
I like to think of this step as giving phlox the best start in life.
Spacing Matters:
For taller varieties like garden phlox, I space them about 18–24 inches apart.
This ensures good air circulation, which helps prevent pesky issues like powdery mildew.
For creeping phlox, you can plant closer to create a lush, colorful groundcover.
Prepare the Soil:
I always loosen the soil a bit, mix in some compost for nutrients, and make sure the area is free of weeds.
Planting Depth:
When placing the plant, I make sure the top of the root ball is level with the soil surface.
A Little Extra TLC
Once you’ve got your phlox planted, give it a good drink of water to help the roots settle.
Mulching around the base is also a great way to retain moisture and keep weeds at bay.
Just don’t pile the mulch directly against the stems—that can lead to rot.
Planting phlox is one of those satisfying garden tasks that pays off quickly.
Whether you’re adding a few plants to a flower bed or creating a whole area dedicated to these beauties, a little prep goes a long way in ensuring they grow strong and bloom beautifully.
Trust me, it’s worth the effort!
For more planting inspiration, check out my guides:
Caring for Phlox
Once you’ve got your phlox planted, the real fun begins.
Luckily, phlox is pretty low-maintenance as long as you keep a few things in mind.
Over the years, I’ve picked up some tips that make caring for phlox a breeze and keep it looking its best.
1. Watering
Phlox isn’t overly fussy about water, but it does like consistency.
I make it a point to keep the soil moist, especially during the growing season.
A deep soak once or twice a week works wonders, especially during dry spells.
The trick is to water at the base of the plant, not the leaves—this helps prevent problems like powdery mildew.
2. Feeding Your Phlox
Giving your phlox a little boost with fertilizer can make all the difference in how it blooms.
I like to use a balanced fertilizer in early spring, right when the plants start to wake up.
If they’re looking particularly hungry mid-season, I’ll sprinkle on a little extra food, but don’t overdo it—a little goes a long way.
3. Preventing Powdery Mildew
Powdery mildew can be a bit of a buzzkill, especially for garden phlox.
The key to avoiding it is keeping things airy.
I try to always space my plants properly when I plant them, and I make a point of thinning out any overcrowded stems during the season.
Good air circulation makes a huge difference!
If mildew does show up, I’ve found that spraying the leaves with a mixture of water and a bit of baking soda can help.
4. Deadheading and Pruning
Phlox rewards you for a little extra effort.
Once the blooms start to fade, I snip them off (a process called deadheading).
This not only keeps the plant looking neat but also encourages it to bloom again.
For taller varieties like garden phlox, cutting back the stems by about a third after the first bloom can sometimes bring on a second wave of flowers.
5. Seasonal Care
In Summer: Keep an eye on water levels, especially if the weather’s been dry.
In Fall: After the first frost, I cut back the stems of my perennial phlox to about 2–3 inches above the ground. This helps prevent pests and diseases from overwintering.
In Winter: Adding a layer of mulch around the base gives the plants a little extra protection against freezing temperatures.
6. Keeping Phlox Happy in Pots
If you’re growing phlox in pots, like annual phlox or smaller varieties, remember that container plants dry out faster.
Check the soil often and water whenever the top inch feels dry.
A good-quality potting mix and regular feeding help keep potted phlox blooming all season long.
Grow more this year with my growing guides:
Propagating Phlox
Propagating phlox is one of those garden tasks that feels a bit like magic—turning a single plant into many!
Whether you’re growing from seeds, cuttings, or dividing established plants, it’s a great way to expand your garden without breaking the bank.
Here’s how to successfully propagate phlox:
1. Starting Phlox from Seeds
Growing phlox from seeds takes a little patience.
You can start seeds indoors about 6–8 weeks before the last frost date.
Here’s how to do it:
Use a seed tray filled with a light, well-draining potting mix. Check out my guide: The Best Seed Starting Mix.
Sow the seeds on the surface and lightly press them into the soil.
Most phlox seeds need light to germinate, so don’t bury them too deep.
Keep the soil consistently moist (not soaking wet) and place the tray in a warm spot with bright, indirect light.
Once the seedlings are big enough to handle, transplant them into individual pots and eventually move them outdoors after the frost danger has passed.
If you prefer a no-fuss approach, you can also direct sow the seeds in the garden in early spring.
2. Propagating Phlox from Cuttings
Propagating phlox from cuttings is quick and easy, and you get an exact clone of the parent plant.
It is best to take cuttings in late spring or early summer when the plants are actively growing.
Here’s how to do it:
Snip a healthy stem about 4–6 inches long, just below a leaf node.
Remove the lower leaves, leaving just a couple at the top.
Dip the cut end in rooting hormone (optional, but it speeds things up).
Plant the cutting in a small pot filled with moist, well-draining potting mix.
Keep the pot in a warm, shaded spot and cover it with a clear plastic bag to create a mini greenhouse.
Within a few weeks, roots usually start to form, and it’s ready to be planted in the garden.
3. Dividing Established Phlox Plants
If you already have a mature clump of perennial phlox, dividing it is a great way to create more plants.
It’s best to do this in early spring or fall when the weather is cooler.
Here’s how to do it:
Carefully dig up the plant, being sure to keep as much of the root ball intact as possible.
Use a sharp spade or knife to divide the clump into smaller sections, each with healthy roots and stems.
Replant the divisions immediately, spacing them out to give them room to grow.
This not only gives you more plants but also helps rejuvenate older ones that might be getting a bit crowded.
4. Propagating in Pots
If you’re short on garden space or just want to keep things portable, propagating phlox in pots is a great option.
Smaller varieties like annual phlox and creeping phlox do especially well in containers.
Make sure to use a high-quality potting mix and water regularly since pots tend to dry out faster than garden beds.
Learn more with my guides:
FAQs
Does phlox bloom all summer?
Some varieties, like garden phlox, can bloom from mid-summer to early fall if properly cared for.
Regular deadheading helps extend the bloom period.
When is the best time to plant creeping phlox?
The best time is in early spring or fall when the weather is cooler.
Can you grow tall phlox in pots?
Yes, but choose a large pot to accommodate the roots and ensure it has good drainage.
Is phlox perennial or annual?
Phlox can be either.
Varieties like Phlox paniculata and Phlox subulata are perennials, while Phlox drummondii is annual.
How tall do phlox grow?
It depends on the variety.
Garden phlox can reach 3–4 feet, while creeping phlox stays low to the ground at 4–6 inches.
What is the best way to prevent powdery mildew?
Ensure proper spacing for air circulation, water the soil (not the leaves), and avoid overcrowding.
For more inspiration, check out these guides:
Wrap-Up
Growing phlox is the best.
Whether you’re admiring the low-growing beauty of moss phlox, the delicate charm of phlox divaricata, or the classic appeal of tall phlox flowers, there’s a variety for every garden.
With the right care and the information shared here, hopefully you’ll enjoy a thriving display, no matter your gardening zone.