Romanesco, the Fractal Vegetable
Brassica oleracea var. botrytis
Family: Brassicaceae
COOL SEASON COLE CROP
Though seen as a type of broccoli, romanesco is actually a selection of cauliflower. It is native to Italy and is believed by experts to have been selectively bred since at least the 15th century. Brassica oleracea species were thought to have originated in Northeast Africa and were spread through the Arabian Peninsula into Asia Minor in the early ages. The various plants within the species were domesticated and bred over time to develop plants with improved traits for cultivation, and Romanesco was developed in the Italian countryside. Romanesco was created by farmers using traditional cross-breeding techniques in the Lazio region of Italy. Experts believe farmers purposely selected plants genetically predisposed to developing naturally spiraled heads, eventually reinforcing the trait over centuries of breeding. Romanesco is named after Rome, the capital of Lazio, and the name was also a descriptor of an ancient dialect spoken within Rome. In the 16th and 17th centuries, Romanesco was recorded in farmhouse booklets, documenting how much the farmers received for growing the plant. In 1834, it was referenced in poet Giuseppe Gioacchino Belli's sonnet "Er Testamento Der Pasqualino," a story about a farmer named Torzetto who grew and sold Romanesco. Romanesco was introduced to the United States in the 20th century and has remained a specialty crop.
Romanesco superficially resembles a cauliflower, but it is chartreuse in color, with the form of a natural fractal. Nutritionally, romanesco is rich in vitamin C, vitamin K, dietary fiber, and carotenoids.
Romanesco heads are one of several plants found in nature that illustrate the Fibonacci sequence, also known as the Golden ratio. This mathematical sequence was created by Italian mathematician Leonardo Fibonacci in 1202, and in simplified terms, it is comprised of numbers that are the sum of the two numbers preceding it. This numbered trend corresponds to a specific ratio that can be expressed through a repeated pattern that takes the shape of a logarithmic spiral in nature. Each Romanesco floret is considered an approximate fractal, as it has a termination point in the center of the spiral, and the number of spiraling florets on the head of Romanesco will always be a Fibonacci number.
Plants take up about a 2x2’ space. The foliage will grow first, eventually starting to produce buds in the middle.
USES
Romanesco has a nutty, earthy, and subtly sweet taste suited for raw and lightly cooked preparations. The entire heads can be cooked whole, or the florets can be separated and cooked in smaller pieces. Romanesco can be utilized in any preparation calling for broccoli or cauliflower, but it is important that the florets are not overcooked, as they can become flavorless and mushy.
Here are some recipes for inspiration.
PRESERVATION
This plant is best used fresh or cooked. Pieces can be broken up and frozen.
GROWING
SEASON & PLANTING
Seed can be started in August and planted throughout the cool season. Plant starters can be used when they become available. Just make sure you have time for the plants to develop. They take some time to develop.
SOIL & NUTRITION
Plant in well-amended garden soil. Feed throughout the season with a general purpose organic fertilizer.
TEMPERATURE & SUN EXPOSURE
Plant in full to part sun. Plants are tolerant of cold, down to 20°F. If the temperature doesn’t linger at that temperature for long (which is often the case where we live) plants will be fine. Mostly it is the buds that get damaged when it gets that cold.
WATER
Provide steady, regular water, as usually found in a garden bed.
HARVESTING
As the buds develop, some people will wrap some of the outer leaves around the buds to help protect them as they get larger. Harvest before the flower buds open up into flowers. People often try for the largest size buds, but the younger buds are more tender and delicious.
WILDLIFE
With warmer weather, noctuid moth larvae may eat holes in the leaves, which is purely cosmetic damage.
INVASIVENESS
Romanesco does not seem to escape cultivation in our region.