Chamomile is a widely appreciated herb, recognized for its delicate, daisy-like flowers and calming properties. This adaptable plant is generally hardy across various growing conditions. Understanding its specific temperature tolerances is important for successful cultivation, allowing it to thrive and produce abundant blooms.
Ideal Temperature Range for Chamomile Growth
Chamomile flourishes within a moderate temperature range, typically performing best when temperatures are between 60°F and 70°F (15°C to 21°C). German chamomile particularly thrives with daytime temperatures around 60-68°F (15-20°C) during its active growth phase. These conditions promote robust plant development, abundant flowering, and optimal production of its essential oils. While chamomile prefers cooler conditions, it can tolerate slightly warmer temperatures, especially with some shade in hotter climates.
Chamomile’s Cold Tolerance
Chamomile’s cold tolerance varies by variety. German chamomile (Matricaria recutita) is an annual plant, completing its life cycle within one growing season. Young German chamomile seedlings can withstand light frosts but typically do not survive hard freezing temperatures. In milder climates, German chamomile often self-seeds, allowing new plants to emerge the following spring.
Roman chamomile (Chamaemelum nobile), a perennial variety, exhibits greater resilience to cold temperatures. This type is hardy in USDA Zone 4 and can endure frosts and even snow. Some sources indicate Roman chamomile can tolerate temperatures as low as 15°F (-10°C), with others suggesting it can withstand temperatures down to -22°F (-30°C). For annual German chamomile, planting seeds indoors six weeks before the last expected frost allows for an early start, or they can be direct-sown outdoors in the fall for spring germination.
Chamomile’s Heat Tolerance
Chamomile can handle summer temperatures up to 100°F (38°C), provided it receives adequate care. In hot climates, providing partial shade during intense afternoon hours helps prevent stress and scorching of blooms. Signs of heat stress include wilting foliage and reduced flowering. If the plant remains droopy despite evening recovery, it signals a need for more water.
Established chamomile plants are drought-tolerant, requiring less frequent watering than younger plants. During periods of extreme heat and drought, however, additional moisture becomes necessary. Timing planting to avoid the most intense summer heat also helps mitigate stress.
Protecting Chamomile from Temperature Extremes
Protecting chamomile from temperature extremes involves several strategies. For cold protection, apply a thick layer of organic mulch, such as straw or wood chips, around the base to insulate roots and retain soil moisture. Row covers or frost blankets can provide an insulated barrier against cold snaps and icy winds. Container-grown chamomile can be moved indoors to a bright, sheltered location when temperatures drop significantly.
During hot weather, ensure consistent moisture, especially for young plants, which need about one inch of water per week. Spacing plants 8 to 12 inches apart improves air circulation, helping to cool them. A layer of mulch also helps keep the soil cool and moist, reducing the impact of high temperatures on the root system.