The Sharwil avocado is a cultivar of Persea americana, a species within the Lauraceae family, which includes plants like cinnamon and laurel. Botanically, it’s classified as a berry, featuring a single large seed surrounded by fleshy pulp, though it’s commonly treated as a vegetable in culinary contexts. Sharwil is a hybrid of Guatemalan and Mexican races, with the Guatemalan influence (roughly 60-70%) contributing to its rich, oily flesh and the Mexican lineage (30-40%) enhancing its cold tolerance and smaller seed size. As a Type B flowerer—female in the afternoon, male the next morning—it’s partially self-fertile but benefits from cross-pollination with Type A varieties, a trait tied to its synchronous dichogamy flowering behavior.
Originating in Queensland, Australia, the Sharwil avocado emerged as a chance seedling on Frank Sharpe’s property near Brisbane in the late 1940s. Named after Sharpe and James Wilson, who introduced it in 1954 after acquiring the land, it blends their surnames into “Sharwil.” By 1966, scions reached Hawaii, where it thrived in the Kona region’s volcanic soil and tropical climate, becoming a major commercial variety. Its success in Hawaii led to its prominence as the only avocado approved for export to the U.S. mainland under strict USDA regulations, following a fruit fly scare in 1992 that was resolved in 2013 with a systems approach. Though its parents are unknown, speculation points to Edranol as a possible contributor due to similarities in leaf and fruit traits.
Identifying a Sharwil avocado is straightforward. It’s medium-sized, pear-shaped, and narrow, measuring 8 to 13 centimeters long and 5 to 7 centimeters wide, typically weighing 8 to 16 ounces (225-450 grams). The skin is rough, bumpy, and green, staying green when ripe—unlike Hass, which darkens. Its creamy, light green flesh, making up about 74% of the fruit, surrounds a small, round seed, offering more edible yield than many varieties. Early-season fruit is firm, like cool butter, while late-season fruit turns creamier, with a high oil content (around 18-20%) delivering a rich, nutty, buttery flavor and a lingering creamy aftertaste.
Sharwil avocados grow best in USDA Hardiness Zones 9 to 11, favoring warm, subtropical climates with rich, well-drained volcanic or loamy soils. They tolerate brief cold snaps down to 32°F (0°C), thanks to their Mexican genes, but frost damages blossoms and young fruit. Hawaii’s Kona district and parts of Southern California are prime growing areas, where they’re often interplanted with coffee or macadamia nuts. Protection from wind and excessive drought is key, as their medium-thick skin and upright trees are somewhat delicate compared to hardier cultivars.
Seasonality for Sharwil varies by region. In Hawaii, it bears heavily from November to February, with some trees fruiting nearly year-round in optimal conditions, though exports to 32 northern U.S. states are restricted to winter months under USDA rules to avoid fruit fly risks. In California, it ripens from February to May, later than Fuerte but before Hass, while in Australia, it peaks in late spring. Availability is limited outside Hawaii due to its export focus, but it’s prized locally during its season at farmers’ markets or specialty outlets, often marketed as a gourmet option for its quality.
Culinary uses of Sharwil avocados highlight its exceptional flavor and texture. It’s a standout in guacamole, where its high oil content and creamy flesh blend richly with lime and spices, maintaining structure even when mashed. Sliced or cubed, it enhances salads, sandwiches, or sushi, pairing well with seafood or tangy dressings. Its buttery richness makes it ideal for spreading on toast or blending into smoothies, offering a meaty depth that elevates simple dishes. Best enjoyed raw—cooking can dull its taste—it’s also savored plain with a pinch of salt, a testament to its status as a top-tier avocado among enthusiasts for its balanced, lingering richness.
Cultivation of Sharwil Avocados
Climate Requirements
Sharwil avocados thrive in USDA Hardiness Zones 9 to 11, excelling in warm, subtropical climates with temperatures between 65°F and 85°F (18°C to 29°C). Their Mexican lineage allows brief tolerance down to 32°F (0°C), but frost damages blossoms and young fruit. Growers in Hawaii’s Kona region or California’s coastal zones use windbreaks or sprinklers during rare cold snaps to protect yields.
Soil Preferences
Well-drained, fertile soil is critical, as Sharwil is susceptible to root rot (Phytophthora cinnamomi). Volcanic loam or sandy loam with a pH of 5.5 to 6.5, rich in organic matter, suits its shallow roots—Kona’s ‘a’ā lava soils are ideal. Poorly drained sites require raised beds or heavy compost amendments. Soil testing ensures proper drainage and nutrient levels before planting.
Site Selection
Gently sloping land (5-15% grade) promotes runoff, vital in rainy regions like Hawaii, while full sun—6-8 hours daily—drives fruit production. Wind protection (e.g., natural hills or tree lines) shields its upright trees and medium-thick-skinned fruit from damage. Sites near coffee or macadamia plantations, common in Kona, provide complementary microclimates.
Tree Propagation
Sharwil is propagated by grafting onto hardy rootstocks like ‘Zutano’ or ‘Duke 7’ to ensure disease resistance and consistent fruit traits. Seeds won’t produce true Sharwil fruit due to its hybrid nature, so nursery grafts—scions from certified trees—are grown for 12-18 months before transplanting. This preserves its small seed and rich flesh.
Planting
Trees are spaced 15-20 feet (4.5-6 meters) apart to allow canopy spread, though tighter spacing (12-15 feet) works with pruning in high-density setups. Late spring planting, after frost risk, is ideal in California or Hawaii, giving roots time to establish before summer rains or heat. Holes twice the root ball’s size are enriched with compost, often mounded in wet climates.
Irrigation
Sharwil needs consistent but moderate watering—20-40 gallons (75-150 liters) per tree weekly, adjusted for rainfall, especially in Hawaii’s wet season. Drip irrigation targets the root zone, avoiding excess moisture that invites rot. Young trees require 2-3 weekly sessions, tapering as they mature. Moisture monitoring prevents overwatering in humid conditions.
Fertilization
Nitrogen is applied at 1-1.5 pounds (0.45-0.7 kg) per tree yearly, split into three doses (spring, summer, fall) to match its long fruiting cycle. Phosphorus and potassium bolster fruit quality, often added via balanced fertilizers (e.g., 10-5-10 NPK). Micronutrients like zinc and magnesium, deficient in volcanic soils, are supplemented via foliar sprays, guided by leaf analysis.
Pollination
Sharwil is a Type B flowerer—female in the afternoon, male the next morning—partially self-fertile but yielding better with cross-pollination. Pairing with Type A varieties like ‘Hass’ or ‘Pinkerton’ enhances fruit set, as bees bridge bloom overlaps (October-January in Hawaii, January-April in California). Hives are often introduced to boost pollination in commercial orchards.
Pruning
Light pruning shapes Sharwil’s upright trees, removing dead wood or crowded branches to improve airflow and light in humid climates. Young trees are trained into an open form over 2-3 years, while mature trees get annual thinning post-harvest (spring) to manage fruit load. Heavy cuts are avoided, as its natural vigor supports its medium-sized fruit.
Pest and Disease Management
Avocado thrips and mites are key pests, controlled with predatory insects (e.g., lacewings) or horticultural oils. Root rot and fruit fly risks (notably in Hawaii) are mitigated with resistant rootstocks, strict sanitation, and USDA-compliant heat treatments for export. Regular scouting and debris removal curb issues, especially in wet seasons.
Fruit Development
After pollination, Sharwil fruit matures over 10-12 months, ready for harvest from November to February in Hawaii or February to May in California. It ripens off-tree, with dry matter content (20% minimum) signaling maturity. Fruit weighs 8-16 ounces (225-450 grams), with size tied to water, nutrients, and thinning to prevent branch strain.
Harvesting
Sharwil is picked mature but firm, with clippers cutting stems to avoid tearing its medium-thick skin. Timing aligns with oil content tests, peaking in winter for Hawaii’s export market or spring in California. Workers use ladders or poles, collecting into padded bins to protect its fruit, which bruises less than thin-skinned types but requires care.
Post-Harvest Care
Harvested fruit is cooled to 45-50°F (7-10°C) to slow ripening, then graded for size and blemishes. In Hawaii, export fruit undergoes hot water treatment (e.g., 114°F/46°C for 20 minutes) to meet USDA fruit fly protocols. Ripening occurs off-tree at 65-75°F (18-24°C) over 7-14 days, or faster with ethylene. Mature trees yield 100-200 pounds (45-90 kg) annually with proper management.