How to Grow Shiro Plum

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Shiro Plum

Prunus salicina 'Shiro'

tree

Shiro is a Japanese plum cultivar known for its large, golden-yellow fruits with a sweet, mild flavor and low acid content. It's a vigorous, productive tree that blooms early in spring with fragrant white flowers. The variety is partially self-fertile but produces better yields with compatible pollinators.

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Example Shiro Plum timeline · Pittsburgh, PA (Zone 6b)

Plant Shiro Plum
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Shiro Plum
Late summer into fall

Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Shiro Plum dates for your own zip code.

Growing Conditions

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Sun: Full sun, 6-8 hours daily minimum (8+ hours preferred for best fruit production)

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Water: Regular watering during growing season; provide 1-2 inches per week. Reduce watering after fruit set. Drought-tolerant once established, but consistent moisture improves fruit quality.

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Spacing: 180 inches

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Days to maturity: 2-3 years from planting to first significant fruit production

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Planting depth: Plant grafted trees at same depth as nursery soil line; avoid planting too deep to prevent root rot

Soil

Type: Well-draining loamy to sandy loam soil

pH: 6.0-7.0

Amendments:

Compost or well-rotted manure at planting Balanced fertilizer (10-10-10) in early spring Mulch to retain moisture and regulate soil temperature

Growing Zones

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Thrives in zones 5-9, with best performance in zones 6-8

5a 5b 6a 6b 7a 7b 8a 8b 9a

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Growth Stages

Establishment (Year 1-2)

2 years

Young tree focuses on root development and branch formation. Minimal fruiting; tree develops a strong scaffold structure.

Remove flowers first year to redirect energy to growth. Prune to establish central leader or open vase form. Stake for support in windy areas. Apply 2-3 inches of mulch.

Early Flowering (Year 2-3)

2-4 weeks of flowering

Tree produces fragrant white flowers in early spring before leaves fully emerge. Flowers appear on 1-year-old wood.

Allow some flowering by year 2-3 for fruit set. Thin flowers if heavy crop to prevent overload. Ensure adequate pollinator activity; may need compatible pollinizer tree (Methley, Santa Rosa, or Ozark Premier).

Fruit Development (Late Spring-Early Summer)

4-6 weeks

Small green fruits develop rapidly after successful pollination and flower drop. Fruits begin expanding in size.

Thin fruits to 4-6 inches apart when walnut-sized (golf ball size) to promote larger, quality fruit. Remove damaged or diseased fruits. Maintain consistent watering.

Ripening (Mid-Summer)

4-6 weeks

Fruits grow to full size and change from green to golden-yellow. Interior color changes from light to amber. Flesh softens and sweetness increases.

Reduce nitrogen fertilizer to prevent vegetative growth. Maintain consistent watering to prevent cracking. Monitor for pests and diseases. Fruits ripen over several weeks.

Harvest & Dormancy (Late Summer-Fall)

2-4 weeks harvest, then dormancy October-March

Fruits reach peak ripeness and are harvested. Tree enters dormancy period with leaf color change and drop in fall.

Harvest ripe fruits gently to avoid bruising. Apply dormant oil spray in late fall/early winter. Prune in winter during dormancy to shape tree and remove dead/diseased wood.

Companion Planting

Plan your garden →

Plant with:

Methley Plum Santa Rosa Plum Ozark Premier Plum Borage Comfrey Clover Nasturtium

Avoid planting near:

Black Walnut (juglone toxicity) Fennel (allelopathic) Other shallow-rooted plants competing for moisture

Common Pests

Prune to thin canopy for air circulation; apply spinosad or pyrethrin at petal fall; use pheromone traps; hand-pick infested fruits; clean up fallen fruit daily
Handpick in early morning; use traps away from tree; apply neem oil or pyrethrin; encourage natural predators
Spray with strong water stream; apply insecticidal soap; use neem oil; release ladybugs
Increase humidity; spray with water; apply neem oil or miticide; encourage predatory mites
Improve air circulation; remove infected fruit; apply sulfur or copper fungicide; sanitize pruning tools
Prune out infected branches well below the knot; burn or bury pruned material; apply copper fungicide

Uses

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Fresh Eating & Desserts

Culinary

Shiro plums are excellent fresh-eating plums with a mild, sweet flavor and low acid content that appeals to many palates. They can be used in desserts, jams, preserves, and baked goods. [source]

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Preserves & Jams

Culinary

The fruit's natural sweetness and pectin content make it ideal for making high-quality jams, jellies, and preserves with minimal added sugar. [source]

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Digestive Health

Medicinal

Plums, including Shiro, are traditionally used to support digestive health due to their natural fiber content and sorbitol, which has mild laxative properties. [source]

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Antioxidant-Rich Food

Household

Shiro plums contain phenolic compounds and antioxidants that support overall health and may have anti-inflammatory benefits. [source]

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Pollinator & Wildlife Support

Wildlife

The early spring blossoms attract bees, butterflies, and other pollinators, while ripe fruits provide food for birds and wildlife in summer. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Shiro plums ripen in mid to late summer (typically July-August). Harvest when fruits are fully golden-yellow and yield slightly to gentle pressure. Fruits do not continue to ripen after harvest, so pick only fully ripe fruit. Harvest every 2-3 days as fruits mature over several weeks. Handle gently to avoid bruising; damaged fruit is susceptible to rot. Use a gentle twisting motion or hand-pick to avoid damaging branches.

Fun Facts

🌱 Shiro means 'white' in Japanese, referring to the light golden-yellow color of the fruit and the white blossoms. The variety was developed in Japan and introduced to North America in the mid-20th century.
🌱 Shiro plum trees can live 15-20+ years with proper care, and some well-maintained trees continue producing abundant fruit for 30+ years.
🌱 The tree is partially self-fertile and can set some fruit without a pollinator, but cross-pollination with another Japanese plum variety increases yield by 50-100% and produces larger, higher-quality fruit.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Cultivar Full Sun Mulch Pollination

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