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How To Choose The Best Phlox

how to choose phlox
Tall Garden Phlox

Beautiful and versatile, phlox is one of the most popular plants for gardens new and old. Not only is it fast growing and native to the United States, it’s a favorite with pollinators and will instantly energize your garden with vibrant color and a sweet, clove-like fragrance.

Garden phlox (referred to as Tall, Garden or Tall Garden Phlox) is such a sunny garden favorite that many gardeners don’t realize that there are phlox for woodland and shade environments, rock gardens and small urban gardens too.

Which is the Best Phlox For You?

To figure out which one is right for your garden, let’s look at the three main groups of phlox first:

Three Main Types of Phlox

Garden Phlox - Phlox paniculata (Zones 4-8)

Garden phlox may be a classic choice for an English cottage garden, but it is actually native to the Eastern United States, as are the majority of phlox species. It’s a lovely, clump-forming perennial with an tall, upright habit (24-48”) and a vigorous blooming season that lasts from late spring throughout the summer season.

The 3/4 inch wide fragrant, tubular flowers are held in 6-8 inch panicles at the end of strong stems, and attract pollinators with bright shades of red, pink, purple as well as purest white. Cutting the plant back by a third after blooming will often encourage a second flush of blooms in the early autumn. Foliage is deep green or variegated and lanceolate (spear-shaped).

Garden phlox is considered a sun-loving, cool-garden perennial, but it can be grown in light shade – particularly at the hotter end of its zone tolerance. It prefers moist, well-drained soil and will dry out quickly during periods of drought.

Humidity and drought can also encourage 'powdery mildew' on the leaves, which while rarely fatal to the plant, will disfigure the leaves with white blotching. If you encourage good ventilation around your plants by spacing them well, this can make a big difference.

red super garden phlox
<a href="/perennials/phlox/phlox-red-super">Red Super Garden Phlox</a>

Cultivars are increasingly being bred for greater mildew-resistance, and cutting the plant down by a third to two-thirds after blooming will often result in new foliage and new bonus flowers.

Clumps grow bigger over time, but garden phlox will often spread in beds via seed as well. Unfortunately, the seedlings are rarely true to the parent plant and tend toward a wild magenta color. Luckily, garden phlox is not an aggressive seeder and rogue seedlings are easily removed.

Powdery Mildew is a fungal disease that spreads via water and air and proliferates when soil is dry and air is humid. It is characterized by powdery-white blotches on the upper surface of leaves and while disfiguring, is rarely fatal to the plant.

candy stripe creeping phlox
<a href="/perennials/phlox/creeping-phlox-candy-stripe">Candy Stripe Creeping Phlox</a>

Creeping Phlox - Phlox subulata (Zones 2-8)

In early spring, creeping phlox carpets hillsides, rock gardens and the front of flower borders with intense color, making it a wonderful choice to pair with early spring bulbs that grow above its mat-like habit. Though it also appreciates some moisture in a well-drained site, it copes well in dryer environments and blooms best in full sun.

Half-inch blooms in shades of pink, red, blue, purple or white are held above spiky-yet-soft foliage and give pollinators a reliable food source when the rest of the garden is still waking up.

Creeping phlox is exceptionally hardy and will last for years in the garden. Hillsides and banks that are prone to erosion benefit greatly from planting creeping phlox, as it slowly spreads via roots along its stems.

Once planted, it needs little care from the gardener besides an occasional tidy to remove dead, older areas and perhaps to loosen the soil near recumbent stems to encourage spread.

If planting creeping phlox in a rock garden or in a drier site, make sure to give additional water during the first year so plants can establish well.

Woodland Phlox - Phlox stolonifera/divaricata (Zones 3-8)

An incredibly versatile and hardy perennial, woodland phlox brings color to shady garden spaces and the edges of woodlands – adding a delicate, ‘wildflower’ touch with light, airy flowers in pink, lilac-blue or white. 6-12” tall plants slowly spread into clumps via seeds or creeping stems that root where they touch the ground. In moist, humus-rich soil, a colony can become established fairly quickly.

If you wish to help the process, you can dig and divide the clumps in the spring after flowers have faded. Don’t wait however, as the foliage is soon dwarfed by other plants in the wilder, woodland garden and can become hard to find.

Woodland phlox can also be grown in sunny gardens, but afternoon shade and moist soil is crucial – particularly in hotter zones. If in sunnier, drier spots, the foliage can be disfigured by powdery mildew. Make sure that soil drains well and is rich in organic material.

Consider contrasting the delicate habit of woodland phlox with strong foliage plants such as hosta, or other native beauties like Mayapple or ostrich fern. Or use it as a carpet under tall rhododendrons and other woodland shrubs.

woodland phlox blue moon
<a href="/perennials/phlox/woodland-phlox-blue-moon">Woodland Phlox Blue Moon</a>

What Can Phlox do for you?

Although phlox can be flexible with some aspects of cultivation, carefully matching your garden environment with the right phlox will pay off in thriving, healthy plants in the long run. And, because there are so many wonderful choices, you won’t have to sacrifice beauty or vigor by choosing well.

Is the site sunny or shady? Is the soil rich or poor? Are you looking for early or later bloom?

Browse the following site suggestions to find the phlox:

Best Phlox for Sunny Cottage Gardens

A sunny cottage garden is an exuberant collection of bright flowers and contrasting textures in a wildlife-friendly atmosphere. This is the perfect environment for tall garden phlox in vibrant, happy colors such as Goliath or Red Super, although the classic, mildew-resistant David can act as a beautiful contrast in blooms of pure white.

Edge beds with creeping cultivars like Candy Stripe that will soften pathways and really get the bloom season going in early spring.

In corners of the cottage garden where a little afternoon shade might be present, woodland phlox is a beautiful, delicate accent – particularly paired with bulbs like daffodils and early tulips. Consider the violet-blue blooms of Blue Moon or the exciting reds of Home Fires.

Best Phlox for Shady Woodland Gardens

In all but the deepest, driest shade, woodland phlox will light up the understory with early spring blossoms and won’t compete too much in later summer as larger perennials take over. It’s perfect at the edge of moist woodlands, in hosta beds or near shady streambanks, and brings a ‘wildflower’ look to areas that often get overlooked.

Woodland phlox slowly spreads via seeds and rooting stems and will create a large colony in a few years. Cultivars such as Blue Moon or Sherwood Purple are true favorites in the woodland garden.

If your shady area gets at least four hours of sun and you live in a warm climate (Z6-8), you might want to try a garden phlox in that area. They appreciate a bit of shelter from the sun and heat and will often bloom longer in a part-shade position.

Best Phlox for Rock Gardens, Hillsides or Poor Soils

A tough hillside or rocky area calls for a tough phlox – and that means creeping phlox. Slopes are no problem for this very hardy phlox which spreads via roots along stems that touch the ground. Creeping phlox is especially good along driveways or along the edges of pathways and in areas that don’t get much attention from the gardener.

However, like most perennials, it is important to look after it with adequate moisture as it establishes itself during the first year. If you are in a low-rainfall area, it will require supplemental moisture during the growing season. It’s worth it. The not-to-be-ignored color carpet of creeping phlox will take you by surprise in the early spring. Try Purple Beauty for a huge splash of solid color or treat yourself to Candy Stripe, with novelty bi-colored blooms in pink and white.

Best Phlox for Pollinator Gardens

Pollinators will be attracted to the phlox in your garden no matter which phlox you use. However, if you are specifically planting for pollinators, a brightly colored phlox should be considered over basic whites or pale pastel colors. If you are planting for hummingbird visits, try cultivars in red – one of their favorite colors. StarfireRed Super, and Lord Clayton are all tall garden cultivars that bring scarlet red to the border, and Home Fires creeping phlox will bring the hummingbirds to shadier spots.

If you’re growing a pollinator garden from seed, let Drummond Phlox add to your wildflower mix – it’s a compact wildflower that packs a whole lot of pollinator punch. And don’t forget about creeping phlox! Pollinators are quick to take advantage of early spring blooms when the rest of the garden is just getting started, and will relish the carpet of bloom you provide to them with varieties such as Emerald Blue or Fort Hill.

Best Phlox for Cutting Gardens

One of the best uses for tall garden phlox is as a cutting flower. Flowers give off a light fragrance reminiscent of clove or vanilla and the large panicles of bloom will last well in a vase if picked in the early morning when plump and fresh.

If you are planting phlox specifically for a cutting garden, you don’t need to worry about mildew resistance as you will be harvesting blooms often before mildew takes hold in the garden in the late summer. And, if you’re mixing flowers in the vase, you’ll want to remove most of the foliage anyway. So choose for color! Scarlet red Lord Clayton. Deep purple Laura. Pure white David. There are so many choices for the cutting garden.

Best Phlox for Early Spring Blooms

In full sun, nothing can beat creeping phlox for sheer impact in the early spring. Blooms are prolific and will carpet hillsides, rock gardens and the edges of pathways with bright, vibrant color. Try Scarlet Flame or Emerald Pink, and watch those pollinators flock to the early nectar source! In the shade, woodland cultivars should be your choice such as Home Fires or Blue Moon. They’ll start their show around the same time as creeping varieties, but give the garden a very different, wilder look.

Best Phlox for Summer Blooms

As a rule, cultivars of tall garden phlox are the best to choose from when planting for the summer garden, although there are a few other hybrid species such as Forever Pink that start early and end late. Bear in mind that not all garden cultivars bloom at the same time in the summer. Depending on your zone and microclimate, you can have first bloom as early as the first of June to as late as the first of July. 'Dead-heading' is a sound practice to ensure the longest season for your phlox.

Dead heading refers to the practice of removing flowers or flower clusters as they finish blooming. Doing so often encourages a second flush of bloom or a continuing show of bloom throughout the growing season.

Best Phlox for Hot and Humid Environments

Tall garden varieties bred for mildew resistance, such as David, are usually the best choice for hot climates, but moisture retentive soil is critical to good performance. Additionally a bit of late afternoon shade can spell the difference between success and failure.

Generally, phlox are not a good choice for hot, humid summer gardens, but all groups can grow as far south as Zone 8. If carefully grown in the shade, woodland phlox such as Sherwood Purple will put on a good show in the early part of the season but will die back as summers get hot, so it is a good idea to mix the display with other plants that will take over as they retreat. Creeping phlox will also put on a good display in the spring, but as they are shallowly rooted, they can burn up if summer sun gets too intense.

Best Cold Hardy Phlox

As a whole, phlox is a very cold hardy perennial, but some groups are hardier than others. Topping the list is creeping phlox (Z2) which starts off the early season with a brilliantly colorful display – much appreciated when winters are long.

Woodland phlox is just a little less hardy (Z3) and tall garden phlox the least hardy of these three groups (Z4). Consider using a 2-3 inch mulch of rich compost in autumn on both of these perennials to protect roots and ensure a good start to the upcoming growing season.

Best Phlox for Small Gardens

If you have a small garden, you’re certainly not limited to creeping phlox! Huge advances in breeding have given you plenty of choices for compact cultivars of traditional garden phlox such as Pixie Miracle or Coral Flame. Woodland phlox is also a good choice for your shady areas, as it is compact and delicate and can gently fill in around other, more substantial shade plants.

Small gardens benefit the most from plants with extended bloom times. Forever Pink is a new 'hybrid' phlox that combines a compact size and strong foliage with lovely pink blooms. Those blooms will begin showing off before your compact garden cultivars get going, and with deadheading, will continue the display right into autumn.

Hybrid refers to a plant that is created by crossing two different parent plants – often from different species within the same genus.

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