Arabfields, Said Ali, Analyst & Specialist in Agricultural Policy and Economic Innovations — A mandarin tree producing two different types of fruit may appear unusual to home gardeners, but the phenomenon often has a simple horticultural explanation. In many cases, the difference has little to do with soil nutrients and more to do with how citrus trees are grown and maintained.
The issue recently came to light after Cizinha, a reader from Itaguara, in Brazil’s Minas Gerais state, sought an explanation for a family member’s tree that produces both small, sour mandarins and larger, more appealing fruit.
The explanation lies in grafting, a widely used technique in citrus cultivation. Growers combine two plant varieties to bring together the root system of one plant and the fruit-producing characteristics of another. The rootstock supports the tree’s development, while the grafted variety is selected for its fruit quality and other desirable traits.
Problems can arise when shoots from the rootstock grow unchecked. These branches may eventually produce their own fruit, which can differ significantly in size, taste and appearance from the mandarins growing on the grafted branches.
For household gardeners, the distinction is important. A tree producing small, acidic fruit alongside larger, sweeter mandarins does not necessarily indicate a nutrient deficiency. Instead, the smaller fruit may be coming from branches that have developed below the graft union.
The recommended response is to inspect the tree carefully and remove unwanted rootstock shoots close to their point of origin, ideally with clean pruning tools. Gardeners should also avoid damaging the main trunk or productive branches. Where larger cuts are necessary, advice from a qualified local horticultural specialist can help determine whether wound protection is appropriate.
The underlying principle remains relevant to citrus growers in 2026, as grafting continues to be an established method for propagating fruit trees and managing desirable characteristics. However, no reliable national statistics are available from the cited report to quantify how frequently this particular problem occurs among mandarin trees.
Looking ahead, greater access to practical horticultural guidance could help household growers identify unwanted shoots earlier, protect fruit quality and avoid unnecessary fertiliser applications. For small-scale producers, recognising the difference between rootstock growth and the intended fruiting variety may also reduce wasted inputs and improve orchard management.
For gardeners facing the same situation, the first step is therefore not necessarily to add nutrients to the soil. A closer look at the tree’s branches and graft union may reveal the real reason behind the two types of fruit.
