March 18, 2000

Question: I have a beautiful orange tree in my back yard. It has numerous oranges every year, but they are so sour that I have to throw them away. Is there any way that I can sweeten the oranges?
- Darleen R., Cape Coral

Answer: The sweetness of an orange is determined by its variety and not by color, fertilizer application or any other cultural factors. There are two categories of orange; sour oranges and sweet oranges. Sour oranges are commonly used as rootstocks. The rootstock is the part of a grafted plant that furnishes the root system. Rootstocks are used because of their resistance to deadly soil-borne diseases and parasitic nematodes. They help to extend the life of cultivated trees. Occasionally, the aggressive rootstock growth may overwhelm the slower growth grafted above the union. This is apparently what may have happened in your situation. 

- Stephen Brown is a horticulture agent with the Lee County Extension. To submit questions call the horticulture desk at 461- 7504 between 9 a.m. and 4 p.m. or via e-mail at shb@gnv.ifas.ufl.edu. Listen to the ‘Garden Show" at 8 a.m. on 1200-AM WINK/WNOG.

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