It is now safe to speak openly about beach plums. Here on the Vineyard they are almost all gone, picked by the fanatics or eaten by the birds. Yet on a recent Sunday morning I managed to cadge a perfect six cups worth in a heretofore-unknown-to-me location. They have been cooked down and are currently dripping through the jelly bag (to ensure clear jelly I must not squeeze the bag). To get the three and a half or four cups of juice I need for a jelly recipe, I will need to get into my two remaining frozen bags of plums and add to the fresh batch that I picked on Sunday.

The reason I say it is now safe to discuss is because picking beach plums is another of those competitive, secretive activities that seem to flourish in small communities. Like choice spots for collecting beach glass. Try to get anybody to share a special location for either of these activities.

I am a small-time devotee, happy to make eight or 10 jars of processed jelly and a fifth each of beach plum brandy (using a fifth of decent brandy, two cups of sugar and two heaping cups of fresh beach plums) and beach plum cordial (a fifth of vodka, two cups of sugar, two heaping cups of fresh beach plums, a cinnamon stick, a few whole allspice berries and three or four whole cloves). You can use a jar with a wire latch and a tight-fitting rubber ring. Stir daily until the sugar dissolves, taking care to clean the jar rim and the rubber ring before reclosing. Strain if the plums begin looking raggedy. This stuff will last forever.

For a special treat, sacrifice half a jar of either by removing the plums and adding large pitted prunes for something that is smooth, syrupy and pruney rather than plummy. (Although, actually, prunes are plums.)

The sacred text for beach plum lovers is Plum Crazy, a Book about Beach Plums, by Elizabeth Post Mirel (Clarkson N. Potter, 1973). This little book is the beach plum bible. Betty Fraser did the line drawings inside and the jacket design that is quite perfect. There are copies for sale right now on Bookfinder.com priced between $16 and $50. The book was reprinted as a paperback in 1986 but why not get the out-of-print hardback first edition with the dust jacket since so many are available? A must for any comprehensive home library of Vineyard books.

There are two jelly recipes in the book, one using natural pectin and one that adds commercial pectin. And if you’ve taken the time to remove the pits before you cook the plums in the sugar, you will have a leftover in your jelly bag that Elizabeth Mirel says you can eat like candy. There are other curious recipes like Fire Island Curry, Uncatena Ham and Mystic Peas.

The peculiar crafts and concoctions in the book are probably unnecessary for your repertoire unless you care to make your own face cream or toothpaste. More interesting is the section on dyeing wool. This is one case where you can wring the cheesecloth to your heart’s content to get the maximum amount of purple dye from the plums. And with the addition of iron pills to the dye you can create mauve.

Plum Crazy contains lots of information, including 1602 references to purple plums on Martha’s Vineyard, but perhaps more important is information about the habit of the beach plum. They thrive in loose, sandy soil, so never assume you can rip up a wild plant and move it to your backyard. The roots grow so long and deep in their search for water. Remember to watch out for poison ivy which coexists with beach plum plants. And expect your forearms to be shredded when you poke them into a gnarled plant to gather the plums. It takes a tough plant specimen to survive in the sand.

If you are determined to have your own plants, plan to buy two from your nursery as a single beach plum plant cannot fertilize itself and will never bear fruit.

There are actually domesticated beach plum plants, but the rich heavy soil of an average garden may increase the tannin in the plums and cause the jelling process to be thrown off. Tannin causes the tart taste of the plums but too much unbalances the jelling ratio. You may need to add additional pectin to your recipe if you’ve used plums from a plant growing in amended soil.

As to picking techniques, remember the 1949 classic children’s book Blueberries for Sal by Robert McCloskey? Sal carried her little bucket so that a baby bear followed along behind her and plucked her blueberry harvest from the bucket and ate it all. There are no bears to worry about on the Vineyard, but my friend Ted has another technique: he hangs a bucket around his neck and gathers with both hands. I myself stay on the periphery, lift up the branches and gather the hanging plums from below.

With three plastic containers in my freezer, each containing a recipe’s worth of beach plum juice, I am set for the winter and even next spring. I can whip up a batch of jelly at any time, hoping that I controlled myself back in the fall of 2012 and did not give in to the eternal urge to squeeze the jelly bag. It is the hardest part of the whole process.

And about the location for those last six cups of fresh beach plums, I’ll never tell.

Linda Wilson lives in Oak Bluffs.