Swingle Citrumelo
Also known as: CPB 4475
What's special about Swingle Citrumelo
Duncan grapefruit × trifoliate orange — used mainly as a cold-hardy rootstock; fruit is inedible.
Growing this variety
Swingle Citrumelo follows the same growing basics as Specialty & Hybrid Citrus. Variety-specific maturity above; everything else below applies to the whole Specialty & Hybrid Citrus family.
Germination
Spacing & depth
How to plant
Best grown from a grafted nursery tree for true-to-type fruit and faster harvest. From seed: use fresh seed, plant 1/2 in deep in a well-drained mix, keep 75–85°F and moist. Transplant to a sunny, well-drained site sheltered from cold winds, or grow in a large container (15+ gal) that can be moved indoors below 30°F.
Grower's tip
Odd and cold-hardy citrus crosses — many were bred as ornamentals, rootstocks, or novelty fruit. Poncirus-based hybrids are the cold-hardiest edible citrus.
Woody plant facts
Soil preferences
Deep, rich, well-drained soil with high organic matter.
6.0–6.8 for most; strawberries and blueberries prefer 4.5–6.0.
Compost annually; mulch with wood chips for perennial fruits.
Watering
1–2 in per week; deeper as plants establish.
Soak the root zone, not the foliage. Drip irrigation is ideal for long-lived plantings.
Overwatered: fruit split, root rot, mushy fallen fruit. Underwatered: shriveled berries, dropped flowers, sunscald.
Prefers top-watering — Trees are always top-watered — deep slow soak at the drip line, never at the trunk. Bottom-watering only makes sense for nursery seedlings.
Temperature tolerance
70–85°F (21–29°C)
55–70°F (13–21°C)
Tropical fruits (passionfruit, pepino, naranjilla) frost-tender. Temperate fruits (pomegranate, fig, sea buckthorn) tolerate hard freezes once established.
Container growing
Possible with the right cultivar
10+ gal (38 L) for tree fruit; 3–5 gal for berry canes; 12 in deep for strawberries
Choose dwarf or patio cultivars for containers; overwinter tender types indoors.
Detailed harvesting
Pick fully ripe — fruit sweetens on the plant, not the counter. Test with a gentle tug; ripe fruit releases easily.
Post-harvest storage & preservation
Refrigerate soft fruit unwashed 3–7 days. Freeze on trays, then bag. Dehydrate slices at 135°F. Jam or preserve surplus.
Culinary, medicinal & other uses
Fresh eating, jam, wine, syrup, drying. Use imperfect fruit for cooking; keep the best for the table.
Medicinal or traditional uses are shared for interest only — this is not medical advice. Consult a qualified professional before using any plant medicinally.
Seed saving
Most perennial fruit are insect-pollinated and often not true-to-type from seed.
Named cultivars must be propagated by cutting, division, or graft to stay true.
Rinse seeds from ripe pulp; dry 1–2 weeks. Many need cold stratification before sowing.
Your zone's planting calendar
Pick your USDA hardiness zone and we'll estimate the key dates for specialty & hybrid citrus in your area. These are regional averages — always check your own last-frost forecast before sowing.
My Swingle Citrumelo Specialty & Hybrid Citrus notes
Swingle Citrumelo Specialty & Hybrid Citrus seeds on hand
Track packets and loose seeds you already have. Private to your account.
Par level — leave at 0 for no alert. Anything below par shows on Seed Starting and your shopping list.
From your kitchen — grow specialty & hybrid citrus from what you already have
For fleshy fruits (tomato-family, melons, ground cherries), ferment the seed out. For dry-seeded fruits (roselle, hibiscus family), just let capsules dry on the plant.
- 1Fleshy fruit: scoop seeds and pulp into a jar of water; ferment 2–4 days until it molds; rinse, dry.
- 2Dry-seeded fruit: let capsules turn brown on the plant, then split and tap seeds out.
- 3Perennial fruits (fig, pomegranate, sea buckthorn): far easier from cuttings, division, or suckers than seed.
- 4Store all seed cool, dark, and dry in labeled envelopes.
Storage: 3–6 years dry.
Order more seeds
Running low? Reorder from one of these seed stores.
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Other Specialty & Hybrid Citrus varieties
Oroblanco
Pummelo × white grapefruit — sweet, low-acid, thick pale-green rind. Bred at UC Riverside.
Tavares Limequat
Kumquat × Key lime — small tart-sweet fruit eaten whole; cold-hardier than lime.
Thomasville Citrangequat
Citrange × kumquat — very cold-hardy (to ~5°F); tart fruit usable for juice.
Carrizo Citrange
Washington navel × Poncirus trifoliata — the most widely used commercial citrus rootstock; fruit is bitter.
Troyer Citrange
Sister selection to Carrizo; classic cold-hardy rootstock.
Haruka
Japanese natsudaidai × Hyuganatsu hybrid — pale yellow, mildly sweet, aromatic.
Rough Lemon
Old lemon-like rootstock species; vigorous but fruit is coarse and seedy.
Alemow
Papeda species used as a lemon rootstock; fruit is inedible.
Volkameriana
Lemon × sour orange used as a vigorous rootstock; fruit is acidic and mostly ornamental.