As we head into the short, cold days of the winter solstice is there any food that so evokes thoughts of warm and sunny climes as well as citrus does? As a species, citrus has been cultivated since 3000 BCE and may originated in the area of the Himalayas more than 5 million years ago. Grapefruit, lemons, limes, oranges, and tangerines are among the domesticated sweet-tart fruits of the genus Citrus that we know and love. Most of them are descended from Citrus medica, also known as citron, a large, fragrant citrus fruit. The lemon is a hybrid of citron and bitter orange (Citrus x aurantium), and the many varieties of limes are hybrids of citron, pomelo, mandarin orange and micrantha (a slow-growing, unpalatable species from tropical Asia).
From the top, a pomelo, navel orange, lime, clementine, grapefruit, and in the middle, a lemon.
The Ponderosa lemon, Citrus x pyriformis, is another hybrid of the citron, this time with a pomelo, Citrus maxima. An ever-bearing slow-growing tree with glossy leaves and large ovate fruit, it is often grown as an ornamental plant in Connecticut. Less cold-hardy than a regular lemon, can be grown outside from May to October but will need to be overwintered indoors. I acquired one of these this summer and enjoyed the lovely scent of the large, purple-tinged, blooms each time I passed by it. As of October, none of the many fruit had ripened although they were much larger than the average commercial lemon. I later learned that they can reach the size of grapefruit and that this can take up to nine months!
Ponderosa lemon tree outdoors.
Taking care of a Ponderosa lemon is easy. Keep it in a clay or other porous material container that has good drainage. Allow the top inch of soil to dry out between waterings and then give it just enough to moisten the soil without allowing it to become soggy. When the plant is outside during the warmer months it may require daily watering like other container plants. Back inside, it may benefit from being placed on, but not in, a shallow tray of pebbles and water to keep the humidity level up. A monthly dose of a liquid fertilizer while indoors will benefit it, twice monthly when it is actively growing outside. Ponderosa lemon plants may be grafted onto dwarf rootstocks to keep their size manageable. They may still need some pruning to shape them at any time of the year but keep an eye out for the abundant spines along their branches.
Spines on a Ponderosa lemon tree.
The Ponderosa lemon produces blossoms and fruit year-round. You may wonder how pollination may occur in a home environment where there aren’t any bees or other insects flying about. It is due to the fact that the flowers of the Ponderosa lemon are perfect flowers, containing both male and female reproductive parts within the same blossom. Out of doors the movement provided by a breeze is enough to transfer the pollen grains from the stamens to the stigma. In your home, simply brushing a hand lightly against the flowers can achieve the same result.
So, while the Ponderosa lemon fruit will not be ready for use for a few more months there are still many other varieties of citrus that are ready and willing to grace our holiday tables and treats. For most varieties of citrus, the harvest runs between November and April and possibly into May if the conditions are good. The satsuma, or mandarin, orange (Citrus reticulata) produces fruit from August until December and so it has always been a favorite treat for a Christmas stocking, since the 19th century. We made a Victorian-style ornament from dehydrated slices of oranges, lemons, and limes many years ago and it still graces our tree each year.
The Florida navel oranges, Citrus x sinensis, are at their best from November to January, the California navel from December to May. Using the rind of navel oranges to make candied orange peel is one of the hallmarks of the holiday season for me. Candied, or crystallized, orange peel may seem to be an old-fashioned confection but it is always a popular addition to any cookie tray at the end of a meal. Crystallizing fruit is an easy process of preservation whereby small pieces of fruit or rind are cooked in a simple sugar syrup. When I make candied orange peel for the holidays, I start with 4-5 large navel oranges that have been rinsed and dried. The first cuts remove the navel and stem ends of the fruit. Standing the fruit on one of these flat cuts, cut longitudinal slices of peel away from the inner white pith. These slices often need to be cut lengthwise again into 2 or 3 strips.
When all of the orange peel has been prepared in this way they are put into a saucepan and covered with cold water. Bring them to a boil and then simmer them for 15 minutes. Drain the peel. Repeat this process two more times. This helps to remove bitterness from the peel.
While the peel is draining for the final time, bring one cup of water and two cups of sugar to a boil in the saucepan. Add the drained peel and reduce the heat to a simmer. Allow the peel to simmer until it has become translucent, up to an hour. Transfer the peel to a piece of parchment paper and allow it to cool. Toss the pieces of candied peel in superfine or confectioner’s sugar and allow it to dry overnight.
Keep it in an airtight container and use it to garnish your holiday trays or simply enjoy a few pieces with a cup of tea as you relax in front of the fireplace.
Susan Pelton
UConn Home & Garden Education Center
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