That is certainly not the best time of year to transplant those special plants. However, if leaving them will almost certainly result in their death by crushing, you haven't much choice. You can try digging them up with as many of their roots intact as possible. Those peonies may have massive roots, so you will need to have some strong arms for this job. Is there a shady place where you can either plant or cover their root-balls with soil and keep them moist? If you can get large enough pots, you can certainly pot them up and keep them in the shade. Very hot weather is not the best time to do the job, and every day of delay toward fall is a good thing. Once you know the expected date of construction, pick the coolest day for digging and water the plants well the day before you plan to dig. Overcast and rainy weather would be ideal, but that may not happen. When you dig the lilies, you will need to dig deeply and straight down to avoid severing the stem from the bulb. The lilies need their stems and leaves to feed the bulbs for next year's blooms. The iris are likely to survive this transplanting, as they can be safely divided four to six weeks after blooming. It will be very helpful if you place a mark (with a pen or marker) on the lilies and peonies exactly where the soil touches the stems before you dig them up. Peonies planted too deeply may not bloom, so you want to replant them at the exact same level. We must also warn you that those peonies do NOT like to be disturbed, and they may not bloom again next year even if planted at the correct depth. This would be a good time to get your soil tested, so you can enrich your garden soil with needed nutrients at the same time you loosen the compacted soil prior to replanting. It would also be a good time to incorporate some compost or peat moss into the garden soil.

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