Zinnia

Types of zinnias compared: four garden types from 6 inches to 4 feet tall, and which series resist mildew and leaf spot. Pick for cutting, borders or pots.

Pinch zinnias above the third leaf pair, deadhead to a node and cut leggy plants back by about half. See which of the four cuts your plants need, and when.

Which zinnias fit a 12-inch pot, how often to water, and how to head off powdery mildew. Includes pot-size starting rules, spacing and a symptom-fix table.

Most zinnia bloom-boosters do nothing for flowering — and can hurt your soil’s mycorrhizal fungi. Here’s the soil-test-first feeding schedule that works.

Got white powder, angular brown spots, or leaning stems? This diagnostic table names your zinnia problem in seconds and routes you to the fix.