Illinois Everbearing Mulberry

Illinois Everbearing originated as a chance seedling discovered by Peter Glaser in White County, Illinois, in 1947 on the bottomlands of the Wabash River. It was introduced commercially in 1958 by the Burgess Seed and Plant Co. of Galesburg, Michigan. The plant is a natural hybrid between white mulberry (Morus alba) and native red mulberry (Morus rubra), combining the cold hardiness and adaptability of M. alba with the richer flavor and larger fruit characteristic of M. rubra. Despite the University of Illinois Extension later popularizing it through regional recommendations, the variety was not the product of a university breeding program — it is a naturally occurring cross that was selected for commercialization based on outstanding fruit quality and an unusually long ripening window stretching from late June through late September. Illinois Everbearing is now one of the most widely planted mulberry cultivars in North America and is considered a benchmark against which other mulberry selections are measured.

Adaptability is this cultivar's defining cultural advantage. It tolerates clay, loam, and sandy soils across a pH of 5.5 to 7.0, and once the root system establishes—typically by the second or third growing season—it manages extended dry spells that would stress most stone fruits. Site the tree in full sun for maximum fruit production; partial shade is tolerated but reduces berry set noticeably. During the everbearing fruiting period from late June through early September, consistent moisture supports continuous flush development, so supplemental irrigation during drought in the first few years helps build the canopy that later sustains heavy yields without input. Avoid low spots or areas with prolonged soil saturation; occasional wetness is tolerated, but standing water promotes Phytophthora root stress. Space trees 20 to 30 feet apart to accommodate the spreading 20- to 25-foot canopy at maturity and to allow airflow that reduces foliar disease pressure. The tree grows 3 to 5 feet per year under good conditions, often bearing in its first or second season from a grafted specimen.

USDA Hardiness Zone: 4-9
AHS Heat Zone: 3-9
Chill Hours: 400-600
Sun Requirements: Full Sun to Partial Shade
Soil pH: 5.5-7.0
Soil Type: Adaptable; clay, loam, or sandy soils
Soil Drainage: Well-drained; moderately tolerant of occasional moisture
Water Requirements: Low to Medium; drought tolerant once established
Drought Tolerance: High
Heat Tolerance: High
Plant Spacing: 20-30 ft apart
Container Suitability: Not suitable (large canopy tree); dwarf forms only
How to Prune: Prune during dormancy to avoid sap bleed; can be pollarded or coppiced; maintain as large tree or prune annually to 10-15 ft bush form

At maturity Illinois Everbearing forms a broadly rounded canopy reaching 20 to 35 feet tall with a nearly equal spread, making it a functional shade tree as well as a productive fruit tree. The growth rate of 3 to 5 feet per year means the canopy closes quickly, which suits food-forest canopy and sub-canopy placements. The root system combines a central taproot with spreading laterals; avoid planting within 15 to 20 feet of utility lines, drainage tiles, or shallow foundations. Foliage is dark green through the growing season and turns yellow in fall before leaf drop. The tree produces no thorns, tolerates moderate wind, and carries a moderate salt tolerance useful in coastal-adjacent landscapes. Pruning strategy depends on management goal: left unpruned it becomes a large single-trunk tree; pollarded or coppiced annually it can be maintained as a 10- to 15-foot multi-stem bush that simplifies harvesting. Prune during full dormancy—late winter before bud swell—to minimize the sap bleed that occurs when cuts are made after growth begins.

Mature Height: 20-35 ft tall
Mature Spread: 20-25 ft wide
Growth Habit: Spreading, rounded canopy; large shade tree form
Growth Rate: Fast; 3-5 feet per year
Foliage Type: Deciduous
Food Forest Layer: Canopy, Sub-canopy
Permaculture Role: Fruit tree; wildlife attractor; livestock fodder; dynamic accumulator; coppice/pollard subject
Leaf Color: Dark green
Fall Foliage Color: Yellow
Thorns?: No
Attracts Wildlife: Birds (songbirds, gray catbird, northern mockingbird), foxes, opossums, raccoons, squirrels; host for Red Admiral butterfly
Life Span: 75-125 years

Illinois Everbearing is self-fertile: a single tree will set a full fruit load without a cross-pollinator. Flowers emerge as inconspicuous yellowish-green catkins from early to late April. Pollination is primarily wind-driven, with insects providing supplemental transfer. Because the cultivar is self-fruitful, the practical pollination question is whether to add a companion for yield insurance. Nearby mulberries of any compatible species—including Red Mulberry or White Mulberry—can contribute pollen and modestly increase fruit set on Illinois Everbearing, but neither is required. The everbearing habit itself is not a pollination effect; it results from the tree producing successive flushes of bloom on new shoot growth throughout spring and into early summer, which is why harvest extends well beyond a normal mulberry's concentrated two-week window.

Bloom Season: Early
Bloom Window: Early Apr - Late Apr
Pollination Requirements: Self-fertile; no cross-pollinator required
Pollination Mechanism: Wind pollinated; also insect pollinated
Flower Color: Yellowish-green (inconspicuous catkins)

Berries reach approximately 1.5 inches in length—larger than most native red mulberry fruit—and ripen to a dark reddish-black to deep purple-black. Flavor is extra-sweet with rich, distinctive mulberry character described as resembling blackberry but less tart, with no notable acid bite at full ripeness. Brix measurements at peak ripeness typically run high compared to white-mulberry selections. Texture is soft and very juicy, which means fresh eating window is short: berries deteriorate within one to two days of harvest. Freezing is the primary preservation method and works well; frozen berries retain color and flavor for use in jams, jellies, juice, wine, pies, and cobblers. Young grafted trees produce 15 to 25 pounds annually; a mature tree in good conditions can exceed 100 pounds per season. The continuous six- to eight-week harvest—rather than a single flush—spreads the picking workload, reduces simultaneous competition from wildlife, and aligns with extended canning or fermentation schedules.

Ripening Season: Very Late
Harvest Window: Late Jun - Early Sep
Fruit Size: 1.5 inch
Flavor: Extra-sweet; rich, distinctive mulberry flavor; resembles blackberry
Fruit Color: Dark purple to black when ripe (reddish-black)
Fruit Texture: Soft, juicy
Bearing Habit: Everbearing; continuous production over 6-8 weeks; bears on current season's wood
Years to Bear: 1-2 years (grafted); sometimes first year
Storage Life: 1-2 days fresh; freezes well
Culinary Uses: Fresh eating, jams, jellies, wine, juice, dried fruit, pies, cobblers, smoothies

Popcorn Disease (Ciboria carunculoides) is the most significant disease concern, where this cultivar shows moderate susceptibility. The pathogen infects developing fruit in cool, wet spring weather, causing drupelets to enlarge and fail to ripen. Remove fallen mummified fruit promptly—the fungus overwinters in infected berries on the ground—and maintain ground clearance to allow the canopy floor to dry quickly. Bacterial Blight (Pseudomonas mori) also draws a moderately susceptible rating; infected shoots show water-soaked lesions after frost events that create entry wounds. Prune out symptomatic wood during dry weather and disinfect tools between cuts.

Cercospora Leaf Spot (Cercospora moricola / Cercospora missouriensis), Powdery Mildew (Phyllactinia corylea), and Canker Diseases (Cytospora spp. / Gibberella baccata) sit in the moderately resistant range and rarely cause production loss. Good airflow from proper spacing provides meaningful insurance in humid-summer climates.

Among pests, Scale Insects (armored scales, various spp.) and Stink Bugs (Halyomorpha halys) register as moderately susceptible. Treat scale with OMRI-listed horticultural oil during dormancy or insecticidal soap on crawler-stage juveniles in late spring. Stink bugs are best managed through row covers during ripening combined with trap crops and manual removal. Mulberry Whitefly (Tetraleurodes mori) and Wood Borers (Megacyllene caryae and related spp.) show moderate resistance and are infrequent on vigorous trees.

Popcorn Disease: Moderately Susceptible
Cercospora Leaf Spot: Moderately Resistant
Powdery Mildew: Moderately Resistant
Bacterial Blight: Moderately Susceptible
Canker Diseases: Moderately Resistant
Mulberry Whitefly: Moderately Resistant
Scale Insects: Moderately Susceptible
Stink Bugs: Moderately Susceptible
Hickory Borer / Wood Borers: Moderately Resistant

• Harvest with a tarp: Ripe berries drop freely at peak maturity. Spread a clean tarp beneath the canopy and shake or tap branches to collect fruit quickly — this reduces labor and keeps berries clean.
• Freeze surplus immediately: Fresh berries last only one to two days. Spread unwashed berries in a single layer on a baking sheet, freeze solid, then transfer to freezer bags — the loose-freeze method prevents clumping and preserves texture.
• Manage Popcorn Disease with ground sanitation: Rake and remove dropped mummified fruit each fall and avoid mulching directly with infected debris. This breaks the overwintering cycle before the next spring bloom.
• Monitor for scale during dormant season: Scale insects can build up unnoticed under rough bark. Apply OMRI-listed horticultural oil to the entire canopy during late winter when temperatures are consistently above freezing but before bud break.
• Protect fruit during stink bug pressure: Monitor from July onward in regions where brown marmorated stink bugs are established. Exclusion netting over smaller-trained trees is the most effective organic strategy during peak infestation windows.

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