Ask the gardening expert

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A friend asked me why I thought her daphne odora is sparse in leaves along the stems. I believe it is an older plant. It still blooms, she tells me, but even the bloom is lighter than it used to be. Is there anything she should be doing to bring about improvement in this plant's future performance?

They are such lovely shrubs, but a little picky about growing conditions. An evergreen plant native to Japan and China, it is adored for its early spring, fragrant blooms. An online source claims they will die for no apparent reason and says it's not a long-lived, plant. They commonly show signs of senescing at eight to 10 years.

Sunset Western Garden Book had this amusing comment about daphne odora: "It can die despite the most attentive care, or flourish with little attention until you invite friends over to admire it, at which point it promptly succumbs without warning, just to show you who's in charge."

Thinking ahead to spring: Last year I had many pots 6 inches and larger that had annuals and other things in them. I remember some plants suffered some powdery mildew toward the end of summer. I want to use the pots again, but wonder about the dirt. Am I inviting the same disease again if I use the pots and dirt this spring?

I'd advise against using the soil again. You never know what pathogens are in that pot; the powdery mildew is only the ones you saw and identified. It's a good idea to protect investments by starting clean and fresh. Add the used soil to your compost and let it "cook" for a year before reusing it. At that point, I'd use some only in the lower third of the container, and fresh potting mix for the top thirds.As for the pots, scrub them with a brush and a good sudsy detergent solution; finish with a 10 percent chlorine rinse.Let the pots air dry, and you are good to go.

Celeste Lindsay is a WSU-certified master gardener. Send questions to mslindsay8@gmail.com.