- Mature height
- 3m to 5m
- Mature width
- 3m to 4m
Citrus paradisi 'Rio Red' is the red grapefruit the commercial industry settled on. It was developed at the Texas A&M Citrus Center and released in 1984, and it earned its place by holding deep red flesh right through the season where earlier red selections fade to pink by the end of it.
The fruit is nearly seedless, sweet and low in acid, with a thin skin that often carries a red blush on the outside. That combination of colour, sweetness and no seeds is why it is the red grapefruit most people picture. Ripening runs from winter into spring, and the fruit holds on the tree for weeks once ready, so the harvest can be taken as needed.
The tree is evergreen with a rounded, densely branched canopy of large glossy leaves, and it is self-fertile, so a single tree crops on its own. Fragrant white flowers come through spring and are heavily worked by bees.
Grow it in full sun with free draining soil and shelter from hard frost. Advanced specimens at this size are years ahead of a nursery tube and will crop in their first or second season in the ground.
Frequently Asked Questions
About Citrus paradisi 'Rio Red'
What makes Rio Red different from other grapefruit?
Colour retention. Rio Red holds deep red flesh through the whole season, where older red selections lose intensity as the fruit matures. It is also nearly seedless, sweet and low in acid, which is why it became the commercial standard for red grapefruit.
How does it compare to Ray Ruby?
They are close relatives and both are deep red Texas selections, so there is little to separate them in the fruit. Rio Red is the more widely planted of the two commercially. If you already have one, the other will not give you a noticeably different grapefruit.
Does it have seeds?
Very few. Rio Red is classed as nearly seedless and most fruit carries none, though the odd seed turns up when other citrus are flowering nearby. If you want a guaranteed seedless white grapefruit instead, Marsh is the one to plant.
When does it ripen?
From winter into spring, roughly June to October depending on the district. The fruit holds well on the tree once ready, so you can pick as you need rather than harvesting all at once. Flavour sweetens the longer it hangs.
Does it need a second tree to pollinate?
No. It is self-fertile and crops well as a single specimen. A second citrus nearby will not hurt, but it is not required.
Is it frost tolerant?
Not fully. Like all grapefruit it is frost sensitive, particularly while young. Plant in a warm sheltered position out of frost hollows, and protect through the first couple of winters in colder districts.
How do I care for it?
Water deeply once or twice a week through the warmer months and more often while fruit is filling, since uneven moisture causes fruit drop and splitting. Feed with a complete citrus fertiliser in early spring and again in late summer. Mulch the root zone and keep it clear of the trunk. Remove any shoots below the graft as soon as they appear.
