Growing Phlox
Here are the details you need to keep this perennial flower growing well for you.
Full Sun
Phlox paniculata (tall garden phlox) wants a full sun location or at the least a part sun spot. It will tolerate part shade but will get leggy if you don’t give it enough sun.
If you have a choice, I’d recommend you put it in the morning sun so dew will be dried off the leaves as soon as possible. I’d also put it in a well-ventilated spot in the garden (your windy location).
Because this plant does get powdery mildew with a vengeance if allowed to stay damp and shady. It is the main weakness of the plant and while there are a few “resistant” varieties on the market, they are scant improvements over the main selection unless given excellent growing conditions.
Growing
It grows on a wide variety of garden soils including a heavier almost-clay soil. If you have sandy soils, you simply have to water more to keep the blossoms coming (allowing any plant to dry out will reduce the blossom count).
Getting more is as simple as digging up a chunk of the root in the spring and moving it. Do this before or just as active growth starts. Fall division is also a recommended practice and I’ve moved quite a few of them this way. See the pages on plant division for details on how to do this.
Fall Care
Fall care is simply to cut the plant to the ground. Leave a few 6-inch long stubs so you know where the plant is in the spring. Generally, remove the stems and leaves from this plant to your landfill – do not compost them in your own garden. The stems and leaves will be full of powdery mildew spores.
Because the plant is a mid to late summer bloomer, deadheading will not extend the bloom. But deadheading will make the plant look better and will make the remaining blooms look better. So do remove any spent or fading flower heads. Just snip them back so you can’t see the stems that supported them without removing any other blooms.
Heavily growing phlox will start as a small gallon plant and will expand to 12 in the second year. After that it slows down a little but will eventually occupy an area 18-24 inches wide.
If you want one of those magnificent shows seen in garden magazines, you’ll have to plant several specimens 12-18 inches apart to give a full “blowsy” look. You can give it 4-5 years in one spot to get it up to 30 inches or so wide. After that, you’ll find you want to divide it to improve the blooms and give it a renewed life.
Growing phlox in a full sun perennial cottage garden is almost a necessity. Just pick the newer disease resistant varieties that are coming onto the market now.
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