The Kelsey plum tree bears unique plum fruit. This unique plum fruit is heart-shaped. It has brilliant green skin, standing out in bins of ordinary red or purple plums. The bright green skin slowly turns yellow with splashes of red as the fruit ripens. The freestone flesh of the pum is golden, rich, juicy, and aromatic, and the pit inside the fruit is small.
Kelsey plum trees are disease-resistant and heavy bearing. Kelsey plum fruit is easy to transport and keeps well. For many home producers of plums and many commercial orchards, the Kelsey plum is the variety of plum they cannot be without.
History of the Kelsey Plum Fruit and Kelsey Plum Tree
The Kelsey plum tree is often described as “no ordinary Japanese plum.” It has been a favorite of American plum growers for decades, but its origins trace back to the Japanese plums, and before that, to central China. But its amazing fruit features were the result of American improvements to the plant.
“Japanese” plums arrived in Japan about 1,000 years ago from central China. These early ancestors of the Kelsey plum tree were cultivated for making pickles and sake, but they also escaped cultivation and started growing in the wild.
Japanese plums thrived at higher elevations in Japan’s southerly islands. Like all plums, they need cooling hours to bloom each spring, but these hardy trees don’t always drop their leaves each fall.
Plums were unknown in Europe until Portuguese missionaries brought some back from Nagasaki in the 1500s. Japanese plums didn’t catch on in Europe, and they were unknown in the United States until Japan was reopened to international trade in 1854.
Sixteen years later, a botanist at the University of California named John Kelsey visited Japan and brought back samples of plums previously unknown in the United States. Kelsey was surprised to learn that Japanese plums were well-suited to dry-summer cultivation in California. He gave a sample of the seeds to the famed plant breeder Luther Burbank, who in a few years had created the cultivar we now know as the Kelsey plum.
Kelsey plums continue to be regarded as premium fruit trees in the twenty-first century, but you won’t always find a “Kelsey plum” in a nursery. Kelsey plum’s need to be pollinated by other varieties to bear fruit. Growers solve this problem by grafting scions of Kelsey plums onto other varieties of plums to make sure that the Kelsey plum blossoms receive the pollen they need.
Kelsey Plum Tree / Fruit Characteristics
Kelsey plum trees, that is, plum trees grown on Kelsey plum rootstock, usually grow 10 to 15 feet (3 to 5 meters) tall and a little wider, about 12 to 18 feet (4 to 6 meters) across. They bear abundant white blossoms with green centers after they have received 400 chill hours (exposure to temperatures between 32 and 45 degree Fahrenheit/ 0 to 7 degrees Celsius).
Fruit trees don’t give gardeners instant gratification, but the Kelsey plum tree comes as close as possible. You will usually get flowers the year after you plant the tree. Kelsey plum trees, if they have a pollinator nearby, will bear fruit the second year. Branches are covered with thousands of blooms that mature and fall to reveal lustrous dark-green or reddish-brown bark below.
The usual advice for planting Kelsey plums is that they can be grown in USDA Hardiness Zones 5 through 9. You won’t be able to grow them in USDA Hardiness Zones 5 through 7, however, if your winters are marked by chinook winds or prolonged warm spells. The plums get confused by interruptions in below-freezing weather. There will be a few years in USDA Hardiness Zone 9 that your Kelsey plum tree won’t get enough chilling hours.
If you grow a tree on Kelsey plum rootstock (that is, not Kelsey plum scion grafted onto some other tree), you can expect a tree that grows on a single trunk in an oval habit, wider than it is tall. To accommodate the 10 to 15 foot (3 to 5 meter) height and 12 to 18 foot (4 to 6 meters) width of the mature tree, plant young apricot trees about 21 feet (7 meters) apart in all directions. Make sure they are planted at least 21 feet from the foundations of any building, too.
You’ll never get Kelsey plums unless you also have some other variety of plum nearby. Chilling hour requirements make the selection of plums a little tricky. “Beauty” plums need just 250 chilling hours. Burgundy plums need 250 to 350 chill hours. Usually, Beauty plum blossoms stay open long enough to pollinate Kelsey plums, but if they open and the weather turns warm or hot, then your Kelsey plums may not get pollinated. Burgundy plums are a more reliable pollinator plant for Kelsey plums.
Kelsey plum trees benefit from full sun. They need loose, deep, acidic soil. The pH of the soil should be maintained between 5,5 and 6.5. Boggy, acidic, peaty soils aren’t healthy for Kelsey plum trees even with the addition of lime.
Luther Burbank hybridized the Kelsey plum tree so it does not need a humid, rainy ciate like its Japanese ancestors. Too much wet, cool weather in the spring leads to more cracked fruit and disease.
Kelsey plums aren’t greedy for irrigation. In the summer, you only need to irrigate them by sprinkler every two or three weeks if you keep a 3-inch (75 mm) layer of organic mulch out to the drip line, as far out as the branches extend. Don’t pile mulch directly against the trunk of the tree. Keep about 6 inches (15 cm) around the trunk open.
Trees that are less than 5 years old benefit from 4 to 8 ounces (100 to 200 grams) of 20-0-0 nitrogen fertilizer once a month after they flower until the fruit is picked. Prune Kelsey apricot trees in the winter to remove damaged limbs and to open the canopy to sunlight. Usually you will need to remove about 20% of the limbs.
Pest and Disease Control
Kelsey plums don’t have a lot of pest and disease control. You can stop aphids, mites, and scale by spraying Kelsey plum trees with dormant oil in the winter. Dormant oil smothers scale and kills aphid and mite eggs. Myclobutanil fungicide spray applied before flower buds open in the spring defends against brown rot disease.
Spraying with copper when the leaves begin to drop in the fall stops shot-hole disease. Always use chemical pest control products according to the directions on their labels. Most chemical products have organic alternatives available at many commercial outlets. Your local agricultural extension agent will have more information.
Check out our guide on Pruning Plum Trees here.
Common Uses for Kelsey Plum Fruit
Kelsey plums are delicious eaten raw. You can shred green fruit to make salads similar to a green papaya salad, or you can wait until the skin turns yellow with just a hint of red to eat these plums fresh out of hand. It’s not usually a great idea to eat them directly from the tree, but only because birds and squirrels also like fully ripe fruit.
Other ideas for serving raw Kelsey plums include:
- Kelsey plum salad with black pepper and Parmesan.
- Radicchio and Kelsey plum salad
- Hot cereals with diced Kelsey plums
- Arugula with Kelsey plums and Parmesan
- Kelsey plums with halloumi
- Cold-brewed Kelsey plum iced tea
- Shaved fennel salad with Kelsey plums
- Kelsey plum bruschetta
- Jicama, radish, and pickled Kelsey plums
The possibilities for raw plums are endless. There are endless possibilities for cooked Kelsey plums, too.
Make Kelsey plum james, jellies, ketchup, and chutneys. Use Kelsey plums in cobblers, cookies, cakes, pies, and sauce for pudding and ice cream. Or dry Kelsey plums to concentrate their flavor and nutritional value.
Check Out These Plum Recipes:
Health Benefits of Kelsey Plums
Fresh Kelsey plums are a great source of fiber and a good source of vitamin C. Kelsey plums as prunes have some astonishing health benefits:
- There have been 11 scientific studies of the protective effects of prune against osteoporosis in mature women. It takes about 100 grams (3-1/2 ounces) of prunes a day to make a difference in women’s bone health. Naturally occurring chemicals in prunes prevent loss of minerals in “trabecular” bone, the ends of bones, like the end of the femur at the hip joint.
- Some scientific studies have found that eating prunes prevents arteries from becoming stiff in women after menopause. This effect slightly lowers blood pressure and reduces the risk of blood clots, heart attacks, and stroke.
- Just about everyone knows that eating prunes relieves constipation and improves regularity. Scientists have confirmed that an additional benefit for colon health is stimulating the growth of friendly, probiotic bacteria.
Where Do You Buy Kelsey Plum Trees?
Just about any nursery in northern California stocks Kelsey plum trees. They are available by mail order all over the United States (although there may be shipping restrictions for addresses in Arizona and Florida). Visit Nature Hills Nursery to see all the plum trees they have for sale.
Where To Buy Kelsey Plums
You will find these beautiful green plums on display in July and August at farmer’s markets in California, and as limited specials at produce stores all over the continental United States.