Phlox start flowering in July and come in several intense colors.
(Robert D. Mussey Jr.)
How to make phlox a perennial favorite
Phlox start flowering in July and come in several intense colors.
(Robert D. Mussey Jr.)
If you want a perennial that can make a big, colorful statement this time of year, consider Phlox paniculata. It has the bravura and height (up to four feet) to be the summer garden’s tent pole, no staking required. And its long-blooming thunderheads of flowers - they start flowering in July - come in some marvelously intense colors, such as red, purple, peach, orange, and ravishing shades of pink. Many phlox are bicolors, and some have variegated foliage. They don’t mind heat or humidity if they get enough water, and some even have a nice fragrance.
So why has garden phlox gone out of favor?
Perhaps because these are plants that require a bit of know-how. Sure, they’ll bloom if you don’t do anything to them. But if you want them to look really good you need to employ a few tricks.
1. Don’t let them go to seed. When the flowers have mostly finished blooming, off with their heads! This not only helps conserve strength and encourages rebloom, it also prevents unwanted seedlings from sprouting up around your prized hybrids. Though the parents have clear colors, their offspring will be mostly shades of muddy magenta. Worse still, they will grow more vigorously than their beautiful parents and crowd them out. This is why phlox sometimes seem to “change color’’ after a few years. If you’ve inherited a garden of ho-hum washed-out phlox, discard them and start over. Don’t settle for less than the best. If you see any young seedling sprouting among your hybrid beauties, yank them out like the weeds that they are.
2. If you don’t want seedlings, how do you propagate your phlox? Dig up the roots in September every four years, pull them apart and replant them 18 inches apart in moist, well-drained soil in full sun. You’ll have all the colorful hybrid phlox you’ll need, and they will bloom better because they won’t be overcrowded.
3. Powdery mildew that disfigures the leaves of phlox with a whitish overlay is a common complaint. The easiest way to avoid this is to buy disease-resistant varieties. The best is David, a four-foot tower of cool summer white. Windsor, Alpha, Blue Boy, Prime Minister, and Orange Perfection are also quite disease-resistant, according to studies. Bright Eyes is a longtime favorite that holds up well. I also thin my phlox in the spring by cutting off all but six stems per clump to improve air circulation. And I water with drip irrigation, which wets the roots, not the leaves. If you choose to spray with a fungicide, do it once a month beginning at the end of May before there are signs of mildew. After the fungus shows up, it’s too late to do much about it.
© Copyright 2009 Globe Newspaper Company.
