Eustis Limequat

The limequat was born of catastrophe. After the twin freezes of 1894 and 1895 laid waste to Florida's groves, Walter T. Swingle of the United States Department of Agriculture set out to breed citrus that could shrug off a cold snap, and in 1909 he crossed the sharp little West Indian or Key lime (Citrus aurantifolia) with the round Marumi kumquat (Fortunella japonica). Named and introduced in 1913 alongside a sister seedling called Lakeland, the Eustis limequat stands among the first successful intergeneric citrus hybrids, living proof that two separate genera could be wedded and still bear generous fruit.

The name is a plain-spoken marriage of words, lime joined to kumquat, and the epithet remembers the town of Eustis in central Florida, near the country where Swingle did his work. The kumquat parent contributes far more than a little hardiness. From Fortunella comes the thin, sweet, wholly edible rind that sets a limequat apart from any ordinary lime, so that the whole fruit, skin and all, can be dropped in the mouth or the pot.

The fruit themselves are small and oval, no larger than a big olive, ripening from deep green to a clear yellow across late fall and winter, a season when little else in the garden offers such brightness. Bite through the fragrant peel and the pulp within is fiercely tart and juicy, all Key lime, tempered by the honeyed skin. Cooks prize the Eustis for marmalade and preserves, for a squeeze over fish, and above all for the bar, where a limequat stands in for lime with a sweeter, more aromatic edge. The waxy white blossoms that precede the crop carry the heady orange-blossom perfume common to citrus, sweetening a porch or a greenhouse in spring.

In the garden the Eustis makes a tidy, naturally compact evergreen, reaching perhaps six to eight feet in a pot and taller in open ground where winters allow. Glossy leaves and a rounded, well-furnished habit keep the tree handsome even out of fruit, and a well-grown plant earns a place beside a sunny door, on a terrace, or in a conservatory. Hardier than a true lime yet no lover of hard frost, the Eustis wants full sun, a free-draining soil or a good container mix, and steady water; where winters bite, grow the plant in a pot that can be carried under cover until the cold has passed.