Somerset Seedless Grape

Somerset Seedless is the work of Elmer Swenson, an independent grape breeder in Osceola, Wisconsin, who developed dozens of cold-hardy cultivars outside any university program during a career spanning several decades. The variety carries the selection code ES 12-7-98 and descends from the cross ES 5-3-64 x Petite Jewel, incorporating Vitis labrusca, V. riparia, and V. vinifera lineage — with the riparia influence largely responsible for its strong cold tolerance. Swenson’s breeding objective was seedless, fresh-eating quality in a vine capable of surviving Zone 4 winters without protection, a combination no university program had yet commercialized when Somerset was released. It was among the last introductions before Swenson’s death in December 2004. Somerset typically ripens two to three weeks ahead of Concord-type varieties, giving short-season growers a reliable harvest window that later seedless selections cannot always provide. No plant patent was filed; the variety entered commerce as open propagation.

Somerset Seedless performs best in full sun with at least eight hours of direct light daily; reduced sun delays ripening and cuts sugar accumulation, which matters most for a variety whose chief selling point is early sweetness. Soil pH in the 6.0–6.5 range keeps iron and manganese available, both of which grapes draw on during berry development. The vine tolerates moderately heavy soils better than most vinifera types, but drainage remains critical — standing water at the root zone through dormancy invites Phytophthora and crown decay. Train on a trellis system (two-wire Kniffen or vertical shoot-positioned cordon) to maximize airflow through the canopy, which reduces fungal disease pressure in humid climates. Consistent moisture during the six to eight weeks following fruit set produces uniform berry sizing; drought stress during this window causes berry shatter. Once established, the vine is moderately drought-tolerant between fruit set and veraison.

USDA Hardiness Zone: 4-8
AHS Heat Zone: 1-7
Chill Hours: 150-350
Sun Requirements: Full Sun
Soil pH: 5.5-6.5
Soil Type: Loamy
Soil Drainage: Well-drained
Water Requirements: Regular while young
Plant Spacing: 6-8 ft apart

The vines reach 15 to 20 feet along a trellis if left unpruned, with moderate annual cane extension of 6 to 10 feet under good fertility. Spur or cane pruning each dormant season keeps the canopy to a manageable 6 to 10 feet of trained length per vine, which most home-garden trellis setups accommodate on one or two wire runs. The deciduous foliage is medium green with the lobed leaf shape typical of American-hybrid grapes, turning yellow in fall before leaf drop. Bark shreds in long strips on established canes — a normal characteristic in this lineage, not a sign of disease. Root architecture is moderately vigorous and anchors well in clay-loam soils without requiring rootstock grafting in most northern garden situations. Spacing of 8 feet between vines on a single trellis run is standard; 10 feet suits higher-vigor sites or fertile bottomland soils.

Mature Height: 4-6 ft tall
Growth Habit: Moderately vigorous, procumbent vine
Attracts Wildlife: Birds, butterflies, pollinators, and bees

Somerset Seedless carries perfect (hermaphroditic) flowers and sets fruit without cross-pollination, making it practical for small gardens where planting multiple varieties is not feasible. Bloom occurs in late spring — typically mid-May in a temperate climate — when temperatures are warm enough for reliable pollinator activity. Honeybees and native bees visit the small, fragrant clusters readily. Because berry set from self-pollination can produce slightly smaller clusters than cross-pollinated fruit, pairing Somerset with another early-ripening self-fertile table grape such as Reliance Grape or Vanessa Red Grape is worth considering where space allows — cross-pollen from a compatible neighbor tends to improve cluster fill without changing the variety's flavor profile.

Pollination Requirements: Self-fertile
Pollination Mechanism: Self-pollinating

Berries are small to medium, averaging roughly 0.5 to 0.6 inch in diameter, with thin reddish-blue skin and translucent flesh that parts easily from the vestigial seed trace. Sugar content at full ripeness typically runs 17–19 Brix, producing a noticeably sweet flavor with a distinct strawberry-labrusca aromatic note that separates it from the more neutral vinifera-type seedless varieties. Acidity is moderate, which keeps the flavor balanced rather than cloying. Clusters are small to medium and somewhat loose, which helps airflow but means yields per vine are modest compared to Concord or Niagara. The fruit is best eaten fresh within one to two weeks of harvest; it does not hold on the vine as long as Concord and softens quickly at room temperature. Cold storage at 32–34°F extends shelf life to three to four weeks. The berries also make excellent jam and juice, where the strawberry notes concentrate well.

Fruit Size: 1.5-2 inch
Flavor: Very sweet and tasty
Fruit Color: Red
Fruit Texture: Firm

Somerset Seedless carries moderate resistance to powdery mildew (Erysiphe necator) — an advantage over straight vinifera varieties but not sufficient to eliminate management in humid climates. In regions with warm, wet summers, apply sulfur-based OMRI-listed fungicides preventively every 10–14 days from budbreak through veraison, and prioritize pruning for open canopy architecture to reduce the leaf-wetness periods that powdery mildew exploits. Downy mildew (Plasmopara viticola) susceptibility is moderate; copper-based organic sprays applied before forecasted rain events during shoot growth provide meaningful control. Black rot (Guignardia bidwellii) is the most consequential disease in Eastern climates — remove mummified berries and infected canes promptly, as the fungus overwinters on those structures. Botrytis bunch rot (Botrytis cinerea) risk is elevated in the loose clusters typical of this variety during wet harvest seasons; thin clusters to improve interior airflow and harvest promptly once berries reach target Brix. Grape berry moth (Paralobesia viteana) is the primary insect pest in the Eastern US; pheromone traps for monitoring plus well-timed Bacillus thuringiensis or kaolin clay applications reduce larval damage organically. Japanese beetle (Popillia japonica) skeletonizes foliage in midsummer — hand-picking and neem oil applications limit defoliation on young vines.

• Prune Aggressively Each Dormant Season: Leave only 2–4 canes or 20–40 buds per vine depending on your training system; overcrowded canes shade the fruiting zone and worsen disease pressure throughout the season.
• Harvest by Taste, Not by Color: Berries turn reddish-blue weeks before peak sweetness — taste-test every few days once color is full; a strawberry-forward aroma signals true ripeness.
• Fungal Management Starts at Budbreak: Begin a preventive sulfur or copper program as soon as 1–2 inch shoots are visible; waiting until symptoms appear puts you two weeks behind.
• Remove Mummies After Harvest: Shriveled berries and infected cane stubs left in the vineyard carry black rot and Botrytis inoculum through winter; removing them during dormant pruning cuts next season's disease pressure substantially.

Our 365-Day Plant Guarantee: We ensure that our plants are delivered to you alive and healthy. If your plant does not survive its first year, you're eligible for store credit under these conditions:

1. Your location falls within the appropriate USDA hardiness zone for the plant variety (refer to our hardiness zone map).
2. You maintain the roots' moisture and plant within three days of delivery, following the instructions in our Planting Guide.

If you're concerned about your plant's health, please consult our guide, How to Tell if Your Tree is Dead or Dormant. Remember, our plants are shipped in a dormant state and may leaf out at different times based on their species. To check for plant vital