In addition, some perennials are struggling with a few problems. Daylilies are showing signs of daylily leaf streak and rust. The foliage is yellow, brown and overall raggedy. The best thing to do in this case is to cut them back to the base of the plant.
I have had this happen in the past and I cut them back now to get new growth and new flowers. I have had them blooming in December (with good weather) after doing this.
Of course, the second flush of blooms isn’t that great, but it’s a lot better than brown straggly leaves.
I use this technique (cutting back to the ground or crown) on many other perennials that look awful currently, as well as to deadhead plants such as catmint, yarrow, and other early summer-blooming plants. I simply use my sharp hedge shears to cut the dead flowers and foliage.
The sunflower head-clipping weevil is doing damage to sunflowers and coneflowers. This weevil lays her eggs on the stem of the flowers, about an inch from the flower. The egg-laying results in a broken stem that hangs on by a sliver.
The resulting larvae feed on the dying flower head. Pesticides don’t usually control this pest, handpicking and eliminating the flower heads helps to reduce populations.
Powdery mildew is showing up on many plants, including vegetables (cucumber, squash) and perennials (bee balm, peony, phlox). Once you see the symptoms of powdery mildew, it’s too late to do anything.
In addition, this disease doesn’t usually kill a plant, but it will make it look bad. Controlling powdery mildew is rather difficult. Sprays must be on the plant before the symptoms show up.
However, there are some new products coming down the pike regarding fungicides that might control powdery mildew on tall phlox. Francesca Peduto-Hand, an associate professor at Ohio State University and holds a doctorate in plant pathology,is doing research on this product and was looking for infected plants.
She is placing her research plants near those that are infected and then testing the fungicides on them, once infected. I love research!
I can’t wait for our Perennial for Pollinator research data to be analyzed this fall. Eleven counties around the state are looking at cultivars of native plants to determine what pollinators are visiting. This is a three-year project.
A final research project located at Snyder Park Gardens & Arboretum (Springfield) and Secrest Arboretum (Wooster) has to do with roses and resistance to rose rosette disease. There are four replications of 20 different cultivars. Watch for details in the future!
Enjoy your garden despite the challenges that we face! I know I am.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at bennett.27@osu.edu.
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