Cultivating lavender in Missouri is popular due to its appeal as a fragrant, versatile herb, but its Mediterranean origins present unique challenges in the Midwest climate. The timing of its signature purple blooms is not fixed; it depends on the specific variety planted and local environmental conditions. Understanding this variability is key for a successful lavender harvest. The bloom window is defined by accumulated spring warmth and the onset of summer weather patterns.
Pinpointing the Primary Bloom Window
The main flowering period typically begins in late May and extends through June. This initial display, known as the first flush, offers the most abundant and vibrant blooms of the season. The peak window for viewing and harvesting usually occurs from mid-June to early July, when the fields reach maximum color saturation.
The first buds appear after consistent daytime temperatures follow the last expected frost. Cold-hardy English lavender varieties usually lead the initial bloom. After the large initial harvest, some varieties, if lightly pruned, may produce a smaller rebloom later in the summer. This second flush is less dense and shorter than the primary bloom.
Climate Factors That Influence Timing
The precise start and duration of the bloom are influenced by Missouri’s variable climate, particularly temperature and moisture levels. An early spring with sustained warm temperatures accelerates the plant’s development, causing the first flush to begin sooner in May. Conversely, a cooler, drawn-out spring can delay flowering until later in June.
High summer humidity and frequent rainfall are major factors that can shorten the bloom period. Lavender thrives in dry conditions, and excessive soil moisture combined with high heat can stress the plant. This stress potentially leads to fungal issues that prematurely end the flowering cycle. Microclimates, such as warmer urban settings compared to cooler rural areas, can also shift local bloom times by several days.
Recommended Lavender Varieties for Missouri Growers
Selecting the right variety is essential given the challenges of cold Missouri winters and humid summers. English lavender (Lavandula angustifolia) cultivars like ‘Munstead’ and ‘Hidcote’ are often recommended. They exhibit greater cold hardiness, surviving winter temperatures more successfully than other types, and are the earliest to bloom.
Hybrid lavandins (Lavandula x intermedia), such as ‘Grosso’ and ‘Phenomenal,’ are popular choices for their tolerance to summer heat and humidity. Although slightly less winter-hardy than English varieties, their robust nature and profuse flowering suit the region well. Less suitable varieties, such as Spanish lavender (Lavandula stoechas), struggle to survive the Missouri winter and are not recommended for perennial planting.