Growing cherry trees in Louisiana is complex, depending on the specific type of cherry and the region of the state. Standard sweet and sour cherry varieties, which thrive in colder climates, generally fail to produce fruit in Louisiana’s subtropical environment. The state’s unique climate, characterized by mild winters and high humidity, presents significant challenges to trees evolved for long, cold dormancy periods. However, new low-chill fruiting cultivars and select ornamental species have been developed that can successfully adapt to these conditions.
The Critical Role of Chill Hours
The primary barrier to successful cherry cultivation in Louisiana is the insufficient accumulation of winter cold, known as chill hours. A chill hour is defined as one hour where the temperature remains below 45°F (7.2°C) during the dormant season. Deciduous fruit trees must accumulate a minimum number of these hours to properly break dormancy. This accumulation ensures a uniform bloom and adequate fruit set in the spring.
Traditional sweet cherry varieties, such as ‘Bing’ or ‘Rainier,’ typically require 700 to 1,000 chill hours per year. Sour cherries have even higher requirements, sometimes exceeding 1,200 hours. Louisiana winters do not consistently provide this cold exposure. The northern part of the state might average 600 to 800 chill hours, the central region 400 to 600, and the coastal south only 200 to 400 hours in a typical year. When a high-chill tree does not receive enough cold, it results in delayed, sparse, or uneven flowering, leading to poor fruit production.
Recommended Low-Chill Varieties
Overcoming the chill hour deficit requires selecting specific varieties bred to thrive with minimal winter cold. Low-chill cultivars offer the best chance of success for growing fruiting cherries. The ‘Minnie Royal’ and ‘Royal Lee’ varieties are reliable options, requiring only 200 to 300 chill hours to set fruit. These two must be planted together for cross-pollination, as they are not self-fertile.
Another excellent choice for warm climates is the ‘Royal Crimson’ cherry, which requires 200 to 300 chill hours but is self-pollinating. Varieties like ‘Lapins’ can also be considered, as they are self-fertile and require 350 to 500 chill hours. These low-chill sweet cherries are suited to the central and southern regions of the state, where winter cold is limited.
If the goal is purely ornamental beauty, several flowering cherry trees perform well in the heat and humidity. The Taiwan Cherry (Prunus campanulata) is recommended for its tolerance of high temperatures and vibrant, deep pink blossoms that appear early. The hybrid Okame Cherry (Prunus x incam) also handles the Southern climate well, producing delicate pink flowers. These ornamental selections provide the characteristic spring display without the demanding chill requirements of fruiting varieties.
Essential Care and Maintenance in Humid Climates
Growing any cherry tree in Louisiana’s subtropical climate necessitates a vigilant approach to horticultural maintenance, especially concerning moisture and disease. The high heat and humidity create an environment where fungal pathogens proliferate, posing a constant threat to tree health.
Planting location is paramount, as cherry trees require well-draining soil to prevent root issues. Poorly drained, heavy clay soils common in the region can lead to root rot, often caused by water molds like Phytophthora. Amending the soil with organic matter and planting on a raised mound can significantly improve drainage and air circulation around the roots.
Fungal diseases like Brown Rot (Monilinia fructicola) and Cherry Leaf Spot (Blumeriella jaapii) are major concerns in humid environments. Brown rot attacks both blossoms and fruit, particularly when wet weather coincides with the spring bloom. Preventative fungicide applications are necessary, usually starting at bud break and continuing through the harvest period.
Proper pruning is an important cultural control method that helps manage disease pressure. Opening up the canopy to allow for better air circulation helps leaves and branches dry quickly, making it more difficult for fungal spores to germinate. Careful management of pests, such as leafhoppers that can transmit diseases like X-disease, and regional pests like nematodes, is also advised to maintain overall tree vigor.