Petroselinum crispum aka Parsley

Petroselinum crispum, or parsley, belongs to the carrot family, Apiaceae. Its native range covers northwest Africa and the Balkan Peninsula. It has spread beyond this range through cultivation and naturalization. This herb usually lives for two years. Gardeners often grow it for one season, then replace it. It forms an upright, bushy clump with fine-textured leaves. Growth is moderate, and some plants retain leaves through winter.

First-year plants reach about 1 foot [0.3 m] tall. RHS gives a garden height up to 1.6 feet [0.5 m]. Second-year flower stems can reach 2–3 feet [0.6–0.9 m]. Plants spread about 0.7–1.6 feet [0.2–0.5 m], depending on the source. Young leaves form a rosette close to the ground. The dark green leaves have a scent and divided, pinnate blades. Their outline is triangular, and their surface may look curled or flat. They grow coarser in the second year. The green stems are slender, long, hollow, and hairless.

Small yellow-green flowers open in summer during the second year. They form compound umbels about 0.08–0.25 feet [0.025–0.076 m] wide. Each tiny flower has five petals. Insects pollinate the flowers, and plants can also fertilize themselves. The fruit is a schizocarp, which splits into seed-bearing sections. Small, ridged seeds form from July to September. Plants may seed themselves after flowering. The leaves lose some flavor once flowers appear.

Parsley grows in full sun or partial shade. It needs fertile soil that stays moist but drains well. It accepts sand, loam, and clay across several pH levels. Cool summers suit it better than hot, humid weather. Heat and humidity can make plants wilt. RHS rates its hardiness H6; Missouri Botanical Garden lists USDA zones 2–11. Seeds can take a long time to sprout. Seedlings offer an easier start, but transplanting should spare the taproot. Harvest outer stalks to keep fresh growth coming. Remove flowers when seed is not wanted.

The leaves flavor food and serve as a garnish. Roots also provide flavoring, and the flowers are edible. Parsley fits herb beds, borders, pots, and hanging baskets. Its leaves feed black swallowtail larvae, while flowers attract butterflies. Serious problems are not usual, but leaf spot and stem rot occur. Aphids, carrot fly, leaf miners, and beetles may attack it. Viruses can also affect plants. Normal food amounts are safe, but excessive intake can be toxic. Concentrated essential oil poses a greater risk. Heavy contact may inflame skin. ASPCA lists parsley as toxic to dogs, cats, and horses. Large amounts can cause skin damage when sunlight hits exposed skin. NC State also warns that fruit and seeds poison birds.