What's eating my grefsheim spirea?

Grefsheim Spirea, a white-flowering mounding shrub, shares the spirea family's vulnerability to spirea aphids in spring and spider mites in dry summers. Japanese beetles can skeletonize its foliage in mid-summer. Because Grefsheim flowers very early, its main pest window is the late-spring aphid surge before natural predator populations build up.

Colonies on new shoot tips in late spring cause curled, stunted leaves and honeydew deposits; damage often peaks just after the spring flowering period ends. Spray shoot tips with insecticidal soap or neem oil every 4–5 days. Dislodge colonies with a firm water jet first. Natural predators such as ladybugs typically bring numbers down by midsummer.

Pale, stippled foliage and light webbing on leaf undersides during hot dry summers; foliage may appear bleached or bronzed in severe cases. Improve irrigation during dry spells. Spray both leaf surfaces with neem oil or insecticidal soap weekly for 3 treatments. Mites thrive when plants are stressed — consistent moisture is the best preventive.

Skeletonized leaves with intact veins in mid-summer; adults feed for 6–8 weeks and may migrate from neighboring plants when preferred hosts are stripped. Handpick in the early morning into soapy water. Apply neem oil at dusk as a deterrent. Avoid beetle pheromone traps which increase local pressure.