05/31/2026
The Myth: Mediterranean Herbs Need Extra Care in Summer Heat
Rosemary, thyme, oregano, and lavender are among the most heat-tolerant plants a zone 9b gardener can grow, and they ask for less intervention in summer, not more.
The mistake that kills Mediterranean herbs in hot climates is kindness: overwatering, heavy fertilizing, and excessive protection from the conditions they evolved specifically to thrive in. Rosemary wants dry soil between waterings. Thyme wants to dry out completely between waterings in hot weather. Oregano evolved on dry rocky Mediterranean hillsides and is genuinely drought-tolerant once established. Lavender will rot in heavy, wet soil far more readily than it will suffer from heat or drought.
The correct summer care for established Mediterranean herbs in zone 9b is minimal. Water deeply but infrequently once a week for most established plants, less if there has been any precipitation. Do not fertilize during summer. Do not cover or shade. Do not mist the leaves. The plants are doing exactly what they are designed to do in conditions that suit them perfectly.
What Mediterranean herbs need in zone 9b is excellent drainage. If they are in containers, use a well-draining potting mix and make sure the pot has drainage holes. If they are in the ground, avoid planting in low spots where water collects. In clay heavy Central Valley soil, amend with sharp sand or gravel before planting.
Give them heat, good drainage, and infrequent deep water. That is the entire program.
AuntC 🩷
Source: The Garden Magazine, Fresno CA Zone 9b Planting Guide; Yahoo Lifestyle/Homestead How-To, Gardening Trends 2026; Sow True Seed, Zone 9 Monthly Garden Calendar.