UNITED STATES—Citrus trees are not like deciduous fruit trees. They are not marketable as bare root stock. They do not need winter pruning. Actually, winter pruning might initiate premature growth that is vulnerable to frost. Deciduous fruit trees remain dormant, so can only dream about fruiting for next summer. Citrus trees are happily evergreen, and fruiting abundantly now.

Citrus somehow seem to be more summery than fruit that actually ripen for summer. Iced lemonade is so traditional for warm summer weather. Oranges for Christmas might seem to be out of season when they really are not. Although Mandarin oranges are perishable, other ripe citrus last for weeks or months. Several ripen sporadically throughout the year.

‘Valencia’ oranges, which are the traditional juicing oranges, might last through summer. They may sustain the belief that orange juice is a summery beverage. Several grapefruit cultivars can last about as long. ‘Eureka’ lemon is mostly seasonal, but also generates a few fruits throughout the year. ‘Bearss’ lime may be even more productive out of season.

Citrus fit almost completely into a single genus.

With only one exception, all species and cultivars of citrus are of the same Citrus genus. Kumquats are of the Fortunella genus, but typically qualify as Citrus for simplicity. Citrus fruit is sweet, sour or bitter. Most familiar oranges are sweet. ‘Seville’ is a sour orange for marmalade. ‘Bouquet de Fleur’ is a bitter orange for infusing with Grand Marnier cognac.

Oranges, lemons, limes, grapefruits, kumquats and Mandarins are all very familiar. All of these fruits are available from grocery markets. Their trees grow in many home gardens. Tangerines are simply Mandarins or Mandarin oranges of the Americas. Pomelos, which are larger ancestors of grapefruits, are still uncommon. So are tiny and tart calamondins.

They are not the most unusual, though. Blood oranges provide tangy red juice. ‘Rangpur’ lime is a sour Mandarin orange that is as acidic as a ‘Eureka’ lemon. Tangelos combines the tartness of grapefruits with the sweetness of Mandarin oranges. Sweet limes lack the acidity of typical limes, so are for eating like oranges. These are merely a few examples.

Highlight: ‘Eureka’ Lemon

‘Lisbon’ lemon was the original. It is still a common cultivar for orchard production of fruit for lemon products. Because almost all of its fruit ripens in winter, it can not provide fresh fruit continuously. ‘Eureka’ lemon, which is a mutant of ‘Lisbon’ lemon, may compensate. It is not as productive in season, but only because it also provides lemons out of season.

This complicates orchard harvest, but is justifiable by prolonging the supply of fresh fruit. It is more ideal for home gardens where only a few lemons are needed at a time anyway. Besides, seasonal abundance within home gardens can become too much of a surplus. ‘Eureka’ lemons are not as richly flavorful as ‘Meyer’ lemons, but are more acidically tart.

‘Eureka’ lemon trees, even on dwarfing understock, can eventually grow fifteen feet high. They are generally not quite as wide as they are tall. Their nastily sharp thorns are stout. Vigorous stems develop much longer and potentially dangerous thorns. Foliar fragrance is mild, but can be delightful during warm weather. Glossy evergreen foliage is aromatic when disturbed by lemon collection.

Tony Tomeo can be contacted at tonytomeo.com.