The superb Oriental poppy (Papaver oriental), with its huge red, orange, pink or purple flowers, is spectacular when it blooms in late spring/early summer, but if this is the first time you grow one, a surprise awaits you. This plant has the curious habit of going summer dormant. Yes, its leaves will turn yellow, brown and disappear in summer… and that’s perfectly normal!
Indeed, this oddball perennial has a two-part growth cycle. It begins to produce new leaves in the fall and then stops growing with the arrival of cold temperatures, staying green all winter. Then the plant begins to grow a second time in early spring, adding more leaves to its rosette. In late spring or early summer, it then blooms massively… and starts to go dormant few weeks later.
Don’t make the blunder of trying to “save” the plant by watering it and applying fertilizer. The Oriental poppy is one tough and reliable plant and can live for decades, but it won’t tolerate having its roots flooded by constant watering just as it is trying to go dormant nor being poisoned by excessive fertilization.
Instead, the trick is… to do nothing. Just let it go into its apparent decline. Your plant will thank you for your negligence with even more blooms next year.
If you insist on cutting off the dead leaves, go ahead… it’s your plant after all. But remember that the best fertilizer for any plant is its own decomposing foliage. If you impoverish the soil by removing dead leaves, you’ll need to apply fertilizer (preferably in the fall, when growth resumes) to replace the lost minerals. But you’re then taking two actions (cutting leaves, applying fertilizer) when none at all was required. Not very laidback in my opinion!
But you don’t have to endure poppy leaves turning yellow right in front of your eyes nor a gaping hole in the middle of flowerbed. Just never plant an oriental poppy in the foreground, where its degradation will be in plain sight, but rather in the middle of the bed, surrounded by plants with naturally dense, outward-arching foliage: hostas, daisies, lilies, oriental grasses, Japanese spirea, etc. If you plant them so their leaves touch when they mature, they’ll hide the poppy’s yellowing leaves, allowing them to die with dignity. An easy fix!