Growing The American Plum
When I first heard about American plums I was fascinated. A native plum tree that forms thickets and produces huge amounts of small delicious plums!, I had to experience them. It was years before I found a stand of American plums growing in the wild. Gnarly little trees growing together in a thicket along a stream, they were covered in bright white blossoms. I have since grown out hundreds of seedlings every year and planted as many as I have time for. The American plum (prunus Americana) is a species worthy of the attention of native plant gardeners, wildlife enthusiasts, homesteaders, and even commercial orchardists
The Species: Prunus Americana is just one of several species of native plums. They are extremely adaptable having a native range that stretches across the Northeast, the Southeast, and over through the prairies up to North Dakota. They appear to tolerate just about any soil. I have seen them thriving in heavy clay, dry gravelly soils, and in flood plains. I have read that they can reach heights of 35 feet, but this has not been my observation at all. Every time I have found a stand in the wild, it has never been more than 12 feet tall (I live in upstate NY, so perhaps climate plays a factor in determining size).
American plums are thicket forming. The trees send out runners with sprouts popping up as far away as 10 feet from the base of the trunk.
The trees can be thorny. This varies considerably between individuals, but most do have short sharp spurs.
Growth: American plums hit the gate running. They seem to explode the first few years until flowering begins. I have grown American plums from seed that reached 8 feet with branches their first year. Typically they grow somewhere between 2 and 5 feet the first year. Once they begin flowering and fruiting, growth slows way down and lots of small branches and root suckers develop.
The root suckers can be very prolific. In yards, they are controlled by mowing. However, on the edge of a garden bed they can be difficult to deal with.
Disease and Pests: There are so many pests and diseases of domesticated plums. Somehow, the American plum appears to be resistant to virtually all of them. Black knot is a fungus that destroys European plums in my area. I don’t know if American plum is immune, but it appears to be extremely resistant. I have never heard of a case of black knot in prunus Americana (let me know if you have).
Like all fruit trees, deer love to eat American plum trees' buds and leaves, while voles like to chew the young bark in the winter. Protect your trees with tubes, cages, wraps, or fences.
Flowering and Pollination: This typically occurs around age 3. The flowers really are the best smelling blossoms I have ever experienced. They are white, five petaled, and abundant. Many people report seeing American plums flower but not fruit. This is either from frost damage or a lack of pollination. They flower early, just before apples here, so in some years the crop is lost from a late frost. Pollination is tricky in the wild. Some stands look like several trees, but they are really one tree with many root suckers around it. There need to be at least two different trees close by for pollination to occur.
Propagation: I grow A. plum from seed, others might have experience with cuttings or digging up root suckers. Growing them from seed is not hard but there are a few important things to keep in mind. The seeds need to go through a cold moist period of a few months before they will sprout. You can store the seeds in a bag with moist sand in the fridge or you can store them outside. If you keep them outside, be aware that rodents will eat them if they have access. Plum seeds have a small almond like kernel beneath the shell. Many small critters will do anything they can to eat them. I store my plum seeds outside by burying buckets in the ground. I make small holes in the bucket to allow drainage and fill the bucket with a mix of damp sand and seed.
In the spring, the seeds will most likely be sprouting. Plant them about a half inch deep and cover with a thin mulch. Sometimes plums will enter a double dormancy and not sprout until the following spring. This can be frustrating and is somewhat mysterious. Planting seeds from a cold environment into a warm soil too quickly can often trigger this double dormancy, but sometimes it happens for no apparent reason. I wait until the seeds are actually sprouted before I plant them. I try to plant American plum seeds in the same nursery beds every year because I will usually have two year old seeds sprouting.
It is also worth noting that American plums make very good rootstocks for domesticated plums and peaches. I have grafted lots of varieties onto A. plum rootstocks. Suckers are easily controlled by mowing the grass around grafted trees. The rootstocks are vigorous, precocious, and adaptable to a wide variety of soil conditions.
American plums have been crossed with Japanese plums to create many outstanding varieties that are commercially available. The most famous of these is the Toka plum.
Fruit: The fruit of American plum seedlings is highly variable. It can range in color from yellow to red to pink to purplish. Usually it is a mix of yellow and red blush. The fruits are small, about an inch or two wide. The skin is thick and very tart, but the flesh is usually amazing. The smell and flavor of a good American plum is unbeatable. It surpasses any domesticated plum I have tasted. Because the skin is thick and tart, I like to crack the plums open and eat out the flesh.
They make excellent preserves. I have pitted them and dried them whole, which makes a nice product. They also make great sauces and jams, but the best use for preserving them is fruit leather. Run the pitted fruits through a food mill and spread the pulp on cookie sheets to dry and you will have an amazing fruit leather.
In years with an abundant crop, it is not hard to fill buckets with fruit from a small stand of plum trees. It is a special gift from nature that is ripe towards the end of summer. Watch the crop mature closely. Once the plums start falling, the animals will come from all directions to enjoy the bounty.
I hope that this short article inspires some of you to grow American plums. They are a species that add so much to the hedgerow, garden edge, orchard, streamside, yard, or wild area. They are generous trees showering beauty and fruit on all those near them. I was first inspired to grow American plums after reading about them in Samuel Thayer’s fantastic book Nature’s Garden.