Introduction & History

The Henderson is the Ruby Red's heir — a selection that took Texas's most famous grapefruit and made it redder, sweeter, and more commercially viable. Developed through induced mutation (irradiation) at the USDA station in Weslaco, Texas, and released in 1988, Henderson produces fruit with deeper internal red colouring than the original Ruby Red, which itself was a red sport of the Marsh white grapefruit. The deeper red in Henderson isn't just cosmetic — the lycopene pigments responsible for the colour also contribute to a sweeter, less bitter flavour profile that the modern market demands. Henderson essentially continued the Texas grapefruit colour revolution that began with Ruby Red in 1929, moved through Star Ruby and Rio Red, and reaches its most commercially successful form in Henderson. Today, when you buy 'Ruby Red grapefruit' from Texas at a supermarket, you may well be eating Henderson — the name 'Ruby Red' has become a generic term covering several red grapefruit selections, and Henderson's improved colour has made it the preferred variety among newer Texas plantings.

History & Origin

Developed through irradiation-induced mutation of Ruby Red grapefruit at the USDA Citrus Research Station in Weslaco, Texas. Released in 1988. Named after Dr. Joseph Henderson, a USDA citrus researcher. Part of the continuing programme that produced the Texas red grapefruit series: Ruby Red (1929) → Star Ruby (1970) → Henderson (1988) → Rio Red (1984, released later). Henderson was selected for improved internal red colour and reduced bitterness compared to the original Ruby Red.

Botanical Description

Large evergreen tree, 6-8 m tall, vigorous, with a broad, dense, dome-shaped canopy — typical grapefruit stature. Leaves large, dark green, glossy, 10-14 cm, with broadly winged petioles. Flowers white, large, very fragrant, in clusters. Fruit is large (10-14 cm diameter), round to slightly oblate. Rind is yellow with a pink-red blush, medium thickness. Flesh is deep red — darker than the original Ruby Red, with lycopene pigmentation throughout. Very juicy, sweet with minimal bitterness, in 12-14 segments. Seeds few to moderate (0-6). Tree has few thorns.

Planting & Cultivation

Full sun, well-drained soil, warm location. Space 7-8 m apart — grapefruit trees are large. In Texas's Rio Grande Valley, trees are planted in sandy loam with drip irrigation. Plant in spring. Not suited to small gardens or containers. Choose frost-free locations — Texas grapefruit production is concentrated in the southernmost counties for this reason.

Cultivation

Standard grapefruit management. Feed generously — the large tree and heavy crop demand nutrition. Water consistently; grapefruit requires more water during fruit development than most citrus. The red colour develops best with warm days and cool nights — Texas's autumn climate is ideal. Unlike Star Ruby, Henderson does not have the photosensitivity problems that plagued that variety (Star Ruby foliage burns in intense sunlight). Henderson is a more robust, forgiving tree overall.

Climate & Cold Protection

Hardy to -2 °C (28 °F). USDA zones 9b-11. Grapefruit requires significant heat for fruit quality — the Texas Rio Grande Valley, Florida's Indian River, and similar hot, humid areas are ideal. Cool-climate grapefruit is bland and excessively bitter. Red colour development (lycopene) requires warm days and cool nights during autumn ripening.

Seasonal Care

Spring: Bloom; begin heavy feeding; irrigate. Summer: Active fruit development; consistent watering; nutrient supplementation. Autumn: Red colour developing; maintain water consistency. Winter: Harvest December-April; frost protection critical; post-harvest pruning.

Cold Protection

Grapefruit is among the most cold-sensitive commercial citrus. In Texas, freeze protection includes: wind machines, microsprinkler irrigation, and grove heaters. Dooryard trees need trunk wraps and frost cloth. The devastating Texas freezes of 1983 and 2021 destroyed significant grapefruit acreage. Site selection in the warmest possible location is critical.

Seasonal Care Calendar

Propagation

Budding: T-bud onto sour orange (Texas tradition), Swingle citrumelo, or Volkamer lemon rootstock. The deep-red colour mutation is maintained through vegetative propagation only.

Diseases & Pests

Rio Grande Valley pests: Texas citrus mite, rust mites, whitefly. Greasy spot fungus in humid conditions. In Florida plantings (less common for Henderson), HLB is devastating. Mediterranean fruit fly is a quarantine concern. The thin rind is vulnerable to wind scarring in exposed locations.

Harvesting & Culinary Uses

Henderson ripens December through April in Texas. The red colour deepens as the season progresses — late-season fruit (March-April) has the deepest colour and sweetest flavour. Halve and eat with a spoon, or juice. The reduced bitterness compared to white grapefruit makes it pleasant without sugar. Yield: 100-200+ kg per mature tree. Stores well: 2-3 weeks at room temperature, 6-8 weeks refrigerated.

Culinary Uses

Fresh eating — halve and eat with a grapefruit spoon (no sugar needed for most palates due to reduced bitterness). Fresh-squeezed juice is deeply coloured and sweet — a dramatic improvement over white grapefruit juice. Segments in salads with avocado, shrimp, and bitter greens. Broiled grapefruit with brown sugar and cinnamon. The red colour makes gorgeous cocktails — Paloma, Greyhound, and grapefruit mimosa. Zest for baking and seafood seasoning.

Rootstock Guide

Sour orange: Texas standard, excellent fruit quality, but CTV vulnerable. Swingle citrumelo: CTV resistant alternative. Volkamer lemon: Vigorous for poor soils. Avoid trifoliate orange — causes grapefruit decline.

Container & Companion Growing

Container Growing

Not suitable — grapefruit trees are too large for container culture. Even on dwarfing rootstock, the fruit size and tree vigour make containers impractical.

Companion Planting

In Texas orchards, grapefruit is typically grown in monoculture. In mixed dooryard plantings, the large tree provides shade — underplant with shade-tolerant species. Avoid crowding other citrus too close.

Common Mistakes to Avoid

Planting in a frost-prone location — grapefruit cannot tolerate freezes. Not providing adequate water during fruit development. Harvesting too early before the red colour and sweetness have fully developed. Assuming 'Ruby Red' at the store is always the original Ruby Red variety — Henderson and Rio Red have largely replaced it.

Frequently Asked Questions