Nagami Kumquat TreeCitrus sinensis Kumquats are little jewels of the citrus world. The entire fruit is edible including the sweet, tender skin and sour tart flesh. The olive sized, brilliant orange, Nagami is a favorite kumquat across the US. Heavily perfumed flowers, high fruit production, and few to no thorns make the plant a prize indoors or out. Warm summers bring out an especially enthusiastic show of flowers, which develop into ripe fruit in late winter to early