I have a large urban garden in a NYC park where I serve as a volunteer gardener. I have 4 carex plants all in semi-shady bed areas that have
The location of my garden is Hell's Kitchen Park in Manhattan midtown west (Hell's Kitchen).
Not sure about your Carex problem. But, found this information: Faunal Associations: Little information is available about floral-faunal relationships for Mead's Sedge, although considerable information is available for Carex spp.(sedges) in general. Some insects that feed on sedges include various aphids, leafhoppers (especially Cosmotettix spp.), billbugs (Sphenophorus spp.), larvae of leaf-mining moths (Elachista spp.) and other moths, caterpillars of skippers (especially Euphyes spp. & Poanes spp.), and caterpillars of butterflies (Satyrodes spp.). The foliage of upland sedges in open areas is especially likely to be consumed by various grasshoppers. Among vertebrate animals, the seeds of such sedges are eaten by various upland gamebirds and granivorous songbirds. This includes such species as the Wild Turkey, Greater Prairie Chicken, Ring-necked Pheasant, Mourning Dove, Horned Lark, and Savannah Sparrow. Although it is not a preferred source of food, White-tailed Deer and other hoofed mammalian herbivores browse on the foliage. There is some evidence that the seeds of sedges can pass through the digestive tracts of White-tailed Deer and remain viable, introducing these plants into new areas (Myers et al., 2004).
Carex pansa is amazingly disease and pest free. Overwatering in heavy soils causes root rot. Rust, a foliar disease, may appear under certain overcast or humid conditions, but it generally disappears without treatment or damage to the plants.
Rust, smut and leaf spot. Aphids are possible.
Hope this helps.