It shouldn't hurt to cut peonies this early in Zone 5. Peonies stop growing after flowering and all the rest of the summer just store food in the roots. Right now, your peonies are putting out feeder roots from the tubers to feed next years growth, but the tops are just waiting to brown up. In fact, if it makes you feel better, I'm going to mow mine off this weekend...by choice. Here is a link that might be useful: Garden Musings

I usually set them out already with peppers on them about 2.5 feet high) Last 2-3 weeks depending on the weather they are in the greenhouse set on my deck, with a heater for cold nights and a fan. If my pots are big enough (I use 2.2 quarts) , that schedule works the best for me. First, I have fruit earlier in the season, and by the middle of October when first frost kills perfectly fine plants I have enough frozen and canned for whole winter long. My yard (including house, two sheds, small orchard and huge compost pile) is just 6000 sq feet. And I grow ALL our summer veggies for 2 people, so I can't plant more peppers, to get more crop. I have to keep them longer, an it generally works. My limit is 30 peppers, 10 eggplants, 18 tomatoes. And I have about 80 pot places - home made growing shelf 2X2X7 feet with two layers, each has 8 2-feet long adjustable height lights and can accommodate 20 pots. Whole construction sits near the deck door(the one that doesn't open) facing south. Another location is spare bedroom, where I have two shelves one layer each(2 regular south facing windows ) with adjustable lights as well. They also can take 20 pots each. Normally, by that time they will be already in the green house, but this year winter was terribly long and my last snow just melted a couple weeks ago!

Here in the land of blackspot, I'd gladly take powdery mildew instead. When it pops up occasionally, I hit the rose with a modified Cornell mix, substituting potassium bicarbonate for sodium bicarbonate, using neem oil instead of horticultural oil, and using Dr. Bronner's Castile Soap -- apparently, the peppermint version also makes leaves not as tasty to leaf-eating insects. If leaves have gotten to the disfigured stage from powdery mildew, they won't "bend back to normal" even after using this spray. But the mildew is mostly or entirely gone a day or two after the first spray, and whatever is left is gone after a second spray. Unfortunately, it doesn't do much for blackspot here, but it certainly works for powdery mildew. If you want to try it, I found potassium bicarbonate offered most cheaply at online stores for home brewers. It's also sold as an ingested nutritional supplement. I'm guessing that if it's safe enough for me to consume, it's safe enough for someone who doesn't want to spray a higher-octane fungicide. :-) ~Christopher

Powdery mildew thrives when theres too much nitrogen in the soil (from fertilizing) ,and decreases when you add potassium, into the soil. You can put wood ash if its available, its rich in potassium. That should help with the spreading. At least its said to do so, i havent tried. Got PM on my dahlias the other day (after adding a fertilizer too high in nitrogen). Since ive been watering the plants a lot the reason this year wasnt dry soil. Will be buying a fertilizer low in nitrogen but high in potassium and phosphor. Also made a spray of water, milk, soap and baking soda. If the same plants are getting powdery mildew year after year you can as mentioned throw them out or move them to see if they are more comfortable in another location. PM also benifits from poor light and poor ventilation.