Rhubarb (Rheum rhabarbarum) is a perennial vegetable known for its long, sour leaf stalks, which are commonly baked into pies and sauces. Because of its distinctly tart flavor, it is often prepared and used like a fruit. Its specific growth requirements lead gardeners in warm climates, such as Florida, to frequently question its viability.
The Essential Requirements for Rhubarb Growth
Rhubarb is fundamentally a cold-weather plant that thrives best in regions with long, cold winters. It requires a period of low temperatures, known as vernalization, to stimulate robust growth and produce thick, edible stalks. The crown must be exposed to temperatures below 40°F (4°C) for several weeks to break dormancy and reset the plant’s growth cycle.
Optimal summer conditions involve moderate temperatures, ideally averaging below 75°F (24°C). When temperatures rise significantly above this range, the plant enters semi-dormancy, resulting in thin, less flavorful stalks. Rhubarb also requires rich, well-drained soil with a slightly acidic to neutral pH (6.0 to 6.8). The large crowns are heavy feeders, needing consistent moisture and high organic matter content for sustained vigor.
Why Florida’s Environment is Incompatible
Florida’s subtropical and tropical climate presents significant challenges for perennial rhubarb cultivation. The state, particularly Central and South Florida, lacks the sustained winter chill hours required for vernalization. Without this deep dormancy period, the crowns fail to properly recharge, resulting in weak plants and a failure to produce quality stalks.
The intense summer heat and high humidity are equally detrimental. Temperatures frequently exceeding 90°F cause the plant to wilt and decline rapidly, often leading to premature death. This combination of heat and high moisture creates an ideal environment for fungal diseases and root rot, which are major threats to the plant’s fleshy rhizomes, especially in poorly drained soils.
Gardeners in the northernmost parts of Florida might attempt to grow rhubarb as a short-lived winter annual, but it will not establish itself as a true perennial. These attempts usually yield small, short-lived plants that produce few stalks before succumbing to summer conditions. Furthermore, Florida’s native soil composition, which is often sandy and nutrient-poor, contrasts sharply with the deep, loamy, organic-rich soil that rhubarb prefers.
Alternative Plants for Florida Gardeners
Gardeners seeking to replicate rhubarb’s distinctive tartness in the Florida heat can choose from several excellent, heat-tolerant alternatives.
Roselle (Florida Cranberry)
Roselle (Hibiscus sabdariffa), often referred to as Florida Cranberry, is a popular substitute grown for its fleshy, red calyxes. These calyxes possess a strong, tart flavor that is used to make jams, sauces, and a vibrant tea. This provides a direct culinary parallel to rhubarb.
Cranberry Hibiscus (False Roselle)
Another viable option is Cranberry Hibiscus (Hibiscus acetosella). This plant is grown primarily for its deep red, lobed leaves, which have a tart, slightly citrusy flavor. The young leaves can be harvested and added to salads or cooked dishes to introduce a sour note. Some cooks have specifically used them as a rhubarb substitute in pie recipes. Both Roselle and Cranberry Hibiscus thrive in Florida’s summer conditions and sandy soils.