Beach plum or Prunus maritima is just what it sounds like-- a plum tree that grows along the seashore or sometimes even along lake shores.  It's a small native tree (about ten feet tall at maturity) that can survive some fairly adverse conditions, including salt spray.  The real glory of the beach plum is the fruit.  You can't eat it out of hand unless you like things that are extremely sour, but it makes the most delicious jelly--richly flavored with enough tartness to make it interesting. 

Of course you can buy beach plum jelly in some places and if you are not inclined to grow the tree and make it yourself, you certainly should.  However, the other glory of the beach plum is its fragrant white spring blossoms.  Even if the tree never bore a single plum, the scent would be enough to justify growing Prunus maritima.

In some ways it seems a shame to have to buy a beach plum tree.  It is nicer to find one serendipitously on a beach somewhere.  Most of us are not that lucky, however, so if you have the right sunny spot, beach plum is a great plant to have.  As you might suspect, it likes excellent drainage.  Clay soils are not right for this sand or shale-loving species.   

For those lucky enough to have a beach and the erosion worries that go with it, beach plum is also a worthwhile investment.  Its roots hold the soil, helping to keep the beach in one place so you will have a vactaion spot--plus lots of tasty beach plum jelly--for years to come.