The domestic plum season extends from May through October.
Plums are placed within the Prunoideae subfamily of the Rosaceae, which contains all of the stone fruits such as peach, cherry, and apricot. The subgenus Prunophora contains plums and apricots.
There are more than 140 varieties of plum sold in the United States. The plum is a drupe, a pitted fruit, related to the nectarine, peach, and apricot, but it is far more diverse than its relatives, coming in a wider range of shapes, sizes and especially skin colors. Its flavors also vary from extremely sweet to quite tart. Some plum varieties are specifically bred so that they can be dried and still retain their sweetness, and these are used for prunes. (The Wellness Encyclopedia of Food and Nutrition)
Plums are high in carbohydrates, low in fat and low in calories. Plums are free of sodium and cholesterol. Plums are a good source of vitamin C.
About twenty varieties dominate the commercial supply of plums and most are either Japanese or European varieties. Japanese are the nonprune plums or salicina plums. Originally from China, these plums were introduced into Japan more than 300 years ago. Most varieties have yellow or reddish flesh that is quite juicy and skin colors that range from crimson to black-red. Plums are also used for their juice and often jam or a thick syrup is made out of it. European-type plums are smaller, denser and less juicy than Japanese varieties; their skin color is always blue or purple and their pits are usually freestone, meaning they separate easily from the flesh. The flesh is a golden yellow color. These are the plums made into prunes; a few varieties are sold fresh and called fresh prunes or purple plums. Damson plums are a small-tart European-type variety used mainly for preserves.
California produces about 90 percent of the commercial crop - more than two hundred different varieties that ripen at different times - from early to late summer, with a few in season into the fall. The following dozen, in order of their appearance, account for the lion's snare of the crop.
Early Season Plums
In mid-May, Red Beauts are the first on the market, with Black-Beauts following around Memorial Day. The Red Beaut has a bright red skin and mid-flavored yellow flesh and ranges in size from size to nine plums per pound. The Black Beaut has a thick, tart skin and very juicy flesh that turns reddish as the fruit matures. It closely resembles the Red Beaut, except that the skin is red to purplish black and the fruit runs a bit larger - from four to six plums per pound. Red Beauts stay on the market through early June, Black Beauts until the end of June.
Burbank's classic Santa Rosa comes next, generally on the market from the first week of June through the fourth of July weekend. I like this variety a lot. The plums have a purplish crimson skin with the light freckling that's characteristic of all Rosa type plums. The flesh is tart and red at the pit, radiating into sweet yellow flesh near the skin. The combination gives them their classic sweet-tart plum flavor. Santa Rosas ranges in size from five to eight plums per pound.
Another good plum, the Black Amber, arrives in early June and continues through mid-July. It has a smooth black skin with amber flesh and a small pit. It is flattish in shape and large in diameter. The size ranges from four to six plums per pound.
The Queen Rosa is a lightly freckled, purplish red plum with juicy, mild, light amber flesh. When cooked or raw it has a tangy flavor, but leaving the skin on adds some sweetness to the cooked fruit. It's available from mid-June to mid-July and ranges in size from three to six plums per pound.
The El Dorado is also available from mid-June to mid-July. It ranges in color from bright red to reddish black with a purple tint. The amber flesh is mellow throughout, and although it's juicy, it retains its firmness in cooking and has a good shelf life. Size ranges from five to eight plums per pound.
Of all the plums, many think the LaRoda is the best. It's available from late June through the end of July. It has a freckled dark red to purple skin that occasionally shows a little yellow background. The skin is thin and tender, and the flesh is golden, sweet and juicy. It's great eaten out of hand, and very tangy when cooked unpeeled. The size ranges from four to seven plums per pound.
The Simka, also known as the "New Yorker" variety, is another good one. It's a larger, heart-shaped plum with a red to reddish purple skin, light freckling and firm golden flesh with sweet flavor. It's available throughout the month of July. Size ranges from three to six plums per pound.
The Friar begins the later-season plums, available beginning in July and going through Labor Day. It's about the most popular of all the plums. A mature Friar has a deep black skin and a small pit. The light amber flesh is juicy and sweet, with a contrasting tart flavor in the skin. It ranges in size from three big plums to seven plums per pound, and it keeps well.
The Kelsey is one of the most valuable plums because its bright green skin is a beautiful contrast to the red and purple varieties on display. As it ripens, the skin turns from green to yellow splashed with red. The sweet, greenish yellow flesh is one of the least tart among the plums. The Kelsey is available from the Fourth of July well into August. Size ranges from three to six plums per pound.
The Casselman, which starts arriving in late July, has good holding qualities that make it available throughout September. It has a bright red to crimson exterior and light freckling. The firm, golden flesh has a tangy, sweet flavor when ripe. Most Casselmans weigh in at six plums per pound.
The Angeleno finishes the plum season. It is a heart-shaped plum with a full dark red to purple-blue skin. The light amber flesh is sweet when fully ripe. Harvest begins the third week in August but because of their excellent keeping qualities, Angelenos can be shipped through Thanksgiving. They generally run from four to six and a half plums per pound.
Plums are juiciest at room temperature, but always wash them before eating or cooking. To pit freestone types, cut the fruit in half, twist the halves apart, and lift out the pit. To slice or quarter clingstone plums, use a sharp paring knife and cut through the flesh towards the pit.
European plums are better than Japanese varieties for cooking. Cooked plums are usually eaten with the skins on, but if you need to peel them, first blanch them in boiling water for about 30 seconds.
Baking: Place halved, pitted plums in a baking dish and sprinkle with sugar and spices to taste. Try adding a few spoonfuls of fruit juice, instead of water, and cover. Cook until tender, check during baking and add more liquid, if necessary. Cooking time: about 20 minutes in a 400 degree oven.
Poaching: Plums can be cooked whole (prick them with a fork first), halved, or sliced. For serving whole, cook the fruit unpeeled to retain the shape. Place the fruit in simmering juice, wine, or a mixture of water and sugar and cook until tender. Cooking time: 3 to 8 minutes (European plums cook much faster than Japanese plums).