Answer: Plants can wilt from a lack of oxygen as well as a lack of water. When the soil is compacted, the plant's tender feeder roots and root hairs suffocate. The problem is compounded when the well-meaning gardener assumes that the wilting is a sign of water stress and immediately irrigates. Well-aerated soil, enriched with organic matter, allows both air and water to circulate freely about the root system for a vigorous plant. Roses need one or two deep soakings a week (depending upon weather). If you're watering more often than that (or not as often as that), the wilting could be a sign of water stress.
Best wishes with your roses.
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