The ‘Imperial Epineuse’ plum is a highly regarded classic European plum, recognized for its exceptional flavor and versatility. This heirloom variety holds a special place among fruit enthusiasts. Its appeal stems from a rich, sweet taste and a texture that makes it suitable for fresh eating, preserves, and drying into prunes.
Distinctive Characteristics
The Imperial Epineuse plum is a medium to large fruit, typically displaying an elongated, oval shape with bluntly curved ends. Its skin is thin, smooth, and taut, featuring variegated shades of red, purple, and yellow-green, sometimes deepening in color with increased sun exposure. A powdery white-grey bloom often covers the skin, serving as a protective coating.
Beneath the surface, the flesh is yellow-green, firm, and juicy with a succulent consistency. This freestone variety means the pit is easily removed, a desirable trait for culinary applications. The flavor profile is notably rich, sweet, and refreshing, contributing to its reputation as an outstanding dessert plum.
Historically, the Imperial Epineuse plum is a French heirloom variety. It was discovered as a chance seedling around 1870 in an abandoned monastery near Clairac in southwestern France. The name “epineuse” translates from French to “thorny or prickly,” referring to the thorns that can be found on the plum tree’s branches. This variety was introduced to the United States between 1878 and 1893.
The trees themselves are vigorous and productive, with an upright, spreading habit, reaching heights of 3 to 4 meters (approximately 10 to 13 feet). The fruit typically ripens in late summer through early fall, generally between mid-August and September in the Northern Hemisphere.
Planting and Site Selection
Establishing an Imperial Epineuse plum tree begins with careful site selection to ensure optimal growth and fruit production. Plums generally thrive in USDA hardiness zones 5 through 9. These trees perform best with full sun exposure, ideally receiving at least six hours of direct sunlight daily. Avoiding “frost pockets,” areas where cold air settles, can protect the trees from unseasonable frost damage.
Plum trees prefer well-drained soil, with sandy loam being an ideal type. Good drainage is important to prevent root issues. The preferred soil pH for plums is slightly acidic, typically ranging from 6.0 to 6.8. Incorporating organic compost into the native soil can significantly improve fertility and drainage.
When preparing for planting, dig a hole that is three times the width of the tree’s root ball and as deep as the root ball itself. After placing the tree in the hole, ensure the top of the root ball is level with the ground, then backfill with soil. Initial watering immediately after planting is important to settle the soil around the roots. If planting multiple trees, a recommended spacing of 12 to 16 feet between trees is suggested, allowing ample room for mature size and spread.
Ongoing Care and Maintenance
Consistent watering is important for the health and productivity of Imperial Epineuse plum trees, particularly during their first year and dry periods. Young trees require regular moisture to establish their root systems. Mature trees benefit from at least one inch of water per week, especially when fruit is developing in summer. However, avoid constantly soggy conditions, which can lead to root problems.
Fertilization supports vigorous growth and fruit yields. Annually, top-dressing the soil with compost can provide a steady supply of nutrients. Specific fertilizer applications, if needed, should be based on soil test results, typically in early spring before new growth begins.
Pruning is a regular practice that promotes tree health, fruit production, and airflow within the canopy. Dormant pruning, performed in late winter or early spring before bud break, involves removing dead, damaged, or crossing branches. Thinning cuts can also be made to open the canopy, allowing better light penetration and air circulation. Summer pruning can be done to manage tree size.
Imperial Epineuse plums are generally noted for good disease resistance, though they can be susceptible to bacterial canker. Symptoms of this disease include amber-colored sap exuding from trunks or branches. Applying lime-sulfur or copper sprays in the fall and early spring can help manage bacterial canker. Maintaining a weed and grass-free area around the tree helps minimize competition for water and nutrients. A 4-6 inch layer of mulch can conserve soil moisture and suppress weeds.
Harvesting and Culinary Applications
Determining the ideal time to harvest Imperial Epineuse plums is key to enjoying their full flavor and texture. The fruits are typically ready for picking in late summer to early fall, from mid-August through September. Ripe plums will have a slight give when gently squeezed and will release a faintly fruity aroma. Their skin will display full, rich coloration, transitioning from green-yellow to variegated shades of red, purple, and sometimes dusky burgundy.
Harvesting should be done carefully to avoid damaging the fruit or the tree. Gently twist the plum from the branch; if it resists, it likely needs a few more days to ripen. For best quality and flavor, plums should be enjoyed immediately after ripening. Unwashed plums can be left at room temperature to continue ripening if picked slightly early.
The Imperial Epineuse plum is highly versatile in the kitchen, celebrated for its rich, sweet taste. It excels as a fresh eating dessert plum and can be sliced for cheese boards, salads, or as a topping for breakfast dishes. Beyond fresh consumption, these plums are excellent for cooking and preserving. They are often simmered into jams, sauces, and pastes, or used as fillings for pastries, tarts, and baked goods. In France, Imperial Epineuse plums are traditionally dried into prunes, valued for their concentrated, sticky-sweet flavor. These prunes can be enjoyed as a snack or incorporated into savory dishes.