Southern Louisiana and France share some similarities in climate that allow many French heirloom plants to flourish. However, not all French heirloom vegetables are ideal cultivars for summers in the South Louisiana climate. As the northern edge of the French Caribbean, Louisiana is characterized by a humid, sub-tropical climate, whereas the comparable Côte d’Azur region of the South of France enjoys a Mediterranean climate. South Louisiana, also known as the cultural region “Acadiana”, is in USDA Climate Zone 9a. Southern France and the Côte d’Azur fall between climate zones 9a to 10b. Although temperatures between the two regions are rather similar, a notable difference is the sweltering humidity that descends upon Louisiana in the summertime. Conversely, French summers bring drier weather to accompany its inhabitants along on their sacred, month-long grandes vacances.
The striking difference between humid Louisiana summers, in comparison to dry summers in the south of France, presents limitations for gardeners interested in cultivating a heirloom garden characterized by unique French plant varieties. Below, I provide examples of French heirloom vegetables and culinary herbs that will flourish (or try their best to flourish) in a South Louisiana climate. Fortunately, most popular French heirloom varieties that are unsuitable for Louisiana summers make excellent cultivars in the milder months.
Heirloom Vegetables
For French heirloom vegetables to thrive in Louisiana summers, they must be able to withstand the subtropical heat and humidity. Varieties of beans (Beurre de Rocquencourt), eggplant (Longe de Violette), tomatoes (Marmande) and zucchini (Ronde de Nice) are promising candidates for a heirloom garden. In my experience, antique varieties of French lettuces (Merveille de Quatre Saisons) and carrots (Nantes) fair better as fall and winter crops as they are quickly encouraged to bolt during hot and humid months.
One workaround for growing French heirlooms in Louisiana summers is to strategically plant them where they receive ample morning sun and are able to evade the uncomfortable intensity of afternoon sun and haze. Also, overcompensating for the less than ideal heat and humidity by optimizing soil and moisture conditions is another worthwhile strategy to consider.
French Culinary Herbs
French herbs are a culinary delight. Alas, French herbs tend to be delicate and sensitive to heat and humidity. French tarragon is miserable in South Louisiana gardens in the summer, and is typically replaced with Mexican tarragon due to their similar anise flavor profile. Although French tarragon and Mexican tarragon serve similar purposes, their botanical provenances are different. French tarragon is a member of the aster family, whereas Mexican tarragon is a type of marigold with delicate yellow flowers.
Chervil (French parsley) grows well in South Louisiana in fall and spring. Yet, it tends to bolt quickly in hot and humid summer conditions. Lavender can also be finicky as it enjoys full sun, yet humid conditions are not ideal for this iconic French herb. Afternoon shade for these more delicate herbs may increase their chances of thriving. They also make excellent indoor plants, perched on top of a bright, windowsill ledge in decorative pots. Regardless, as heirloom gardening is a science, I encourage you to tinker with French heirloom plants in different microclimates in your yard to see what works best for your unique conditions.
Jardin & Cuisine 
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