Spider mites are tiny red spiders that feed on plant matter. Signs your hydrangea has spider mites include spider webs over leaves and blooms, and a grainy residue.

Spider mites are common household pests that infest crops and houseplants. ... Annuals and perennials: Hydrangea, marigolds, salvia, New Guinea impatiens, lantana, and viola.

Spider mites are small pests that cause brown specks on plants. To get rid of them, isolate the infected plant and treat with a natural insecticide.