Dividing Phlox Helps to Control Powdery Mildew

As I learned from my Grandma, Phlox are some of the easiest perennials to grow. They’re so forgiving about cultural needs, that it’s tempting to just ignore them. However, when blooms seem to have less pizzazz, it may be a sign that the Phlox is in need of division. That occurs about four to five years after planting. Phlox can be divided in either spring or fall. If the division is made in spring, chances are good for a respectable showing that same season. Fall divisions makes sense, too.

For more on dividing Phlox, see Marianne Binetti’s video, How to divide Phlox.

Dividing Phlox on a regular basis helps keep mildew in check. It improves air circulation around the plant. Rachel Kane, founder of Perennial Pleasures Nursery in East Hardwick, Vermont, specializes in Phlox. She has one of the largest collections of Phlox to be found anywhere in the country. After growing more than 100 varieties of summer Phlox, she reports that many of the older varieties have very good disease resistance.

Rachel Kane’s Advice on Growing Healthy Phlox:

1. Choose varieties that have good mildew resistance.
2. Grow Phlox in a cool location, preferably with shade, and in a humus-rich soil. Their native situation is woodland.
3. If planted in full sun, have other plants nearby to keep the soil around the base shaded.
4. By all means, water when the weather is dry.
5. Reset Phlox every five years in heavily enriched soil (use compost or aged manure).

New Varieties of Phlox Are Brought to Market Most Every Year

There is a resurgence of interest in Summer Phlox (Phlox paniculata). Several new selections debut each season. Breeders look for selections that bloom longer, stand up straighter, and produce more stems and flowers. In the U.S., where mildew is an issue, the new varieties are usually resistant to fungal disease.

When breeders cross two or more species, the resulting plants are commonly referred to as hybrids. Hybrid Phlox bloom earlier than tall garden Phlox, but their height is similar. The hybrids are quite resistant to mildew.

The hybrids bloom early July, right along with Annabelle Hydrangeas and mid-season lilies. The first hybrids were tall — around 30”, but some of the newer varieties, like ‘Kung Fuchsia’ are under two feet tall.

New Varieties of Phlox Make Good Floral Displays

A new series of Phlox bred in the Netherlands is somewhat of an acquired taste. The congested flower heads of the so-called ‘feelings series’ bear shortened, bi-colored petals, giving them the look of a double bloom. All the varieties in the series include the word ‘feelings’ in their titles: ‘Empty Feelings’, Pure, Red, Fancy and ‘Natural Feelings’. The University of Vermont Extension suggests the series was bred for the cut flower market.

Phlox ‘Pure Feelings’ photo by Jean Starr

In an evaluation of Phlox for the Midwest conducted by the Chicago Botanic Garden from 2001 through 2009, project manager Richard G. Hawke said ‘Fancy Feelings’ provides the best floral display of the group with deep pink, strap-like petals and purple sepals that remained ornamental long after the petals dropped. A two-season comparison study of Phlox for the Mid-Atlantic region conducted at Mt Cuba Center in Hockessin, DE, gives insight into the best-performing varieties.

In Gardening, Vintage Never Goes Out of Style

My Grandma came of age during Prohibition and the Marcel hair wave. She became a grandmother in the housedress and apron era. While modern, uber-colorful Phlox varieties of today aren’t visually much different than those offered 100 years ago, their introduction brings Phlox back into the limelight for a new generation of garden-lovers. Even in gardening, vintage never goes out of style.