Winter is the primary season for citrus fruits. Some ripen significantly earlier. Some ripen significantly later. Many citrus trees continue to produce a few fruits randomly throughout the year. Nonetheless, citrus fruits are collectively most abundant during winter. It seems odd that trees that are vulnerable to frost are so productive during the coolest of weather.
Citrus trees are fortunately marginally susceptible to frost in only the cooler climates here. They mostly recover from minor damage where they get a bit too much chill. Those in coastal climates may never experience damaging frost. Some types of citrus are more resilient to frost than others. Vulnerable citrus trees may need frost protection when new.
Home garden citrus trees are different from orchard trees. Most orchard trees, particularly older trees, are standard trees. They grow on standard rootstock that allows them to get larger and, therefore, produce more fruit than dwarf trees. Most home garden citrus trees are dwarf trees. They grown on dwarfing rootstock that keeps them dense and compact.
Furthermore, the many cultivars of citrus that are available for home gardening are more diverse than those that commonly grow in orchards. The Lisbon lemon is very profuse within season, so is preferable for orchards. The Eureka lemon, although a bit less productive, may be a preferable option for home gardens because it produces a few random fruits all year.
Now that citrus fruits are in season, some last longer than others. Grapefruit can hang on their trees for months. They actually develop richer flavor with mellowing tartness as they age. Conversely, Mandarin orange and tangerine are the most perishable citruses. Because the rind is loose, their pulp within begins to oxidize after ripening. Lime eventually gets pithy.
Although this is the time of year to enjoy fresh citrus fruits, it is not the season to do much else with citrus trees. Pruning and application of fertilizer will be more timely after winter. Premature pruning or use of fertilizer is likely to stimulate premature growth. Such growth either languishes through cool weather or succumbs to mild frost.
Highlight: Meyer lemon
Of all the cultivars of citrus that are popular for home gardens, the Meyer lemon is likely the most popular. However, it is not overly common in markets. That may be an incentive for growing it at home. Technically, it is not totally lemon. It is an odd hybrid of lemon and orange. Hence, its fruit has a distinctly rich flavor but a bit less acidity than other lemons.
The Meyer lemon is distinct among citrus trees. It grows more like rigid shrubbery, with a few irregular trunks. Because it naturally develops a compact form, it does not require dwarfing understock. Most old trees, therefore, grew from cuttings, on their own roots. Modern trees commonly grow on understock, though, so can develop suckers below their graft unions.
Fruit of the Meyer lemon is abundant during autumn and winter. Minor quantities ripen through spring and summer also. All Meyer lemon trees from nurseries nowadays are Improved Meyer, whether or not their labels say so. Their improvement was selection of stock that lacks a particular tristeza virus that was inherent to the original cultivar prior to the 1940s.