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Citrus trifoliata

Chinese Bitter Orange · Japanese Bitter-orange · Trifoliate-leaved Orange

Family RutaceaeGenus Citrus

A white flower with narrow curling petals and a green center, on a smooth green twig set with long sharp thorns, beside a round bud.
FlowerAlpsdakeCC BY-SA 4.0

About the plant

What it is and where it grows — not part of any germination protocol.

The plant

Habit
Perennial, Shrub, TreeExtension Gardener Plant Toolbox
Habit
shrub or treePlants of the World Online
Height
8-20 ft2.4-6.1 mExtension Gardener Plant Toolbox
Spread
6-15 ft1.8-4.6 mExtension Gardener Plant Toolbox
Flower
WhiteExtension Gardener Plant Toolbox
Blooms
SpringExtension Gardener Plant Toolbox
Native range
China North-Central, China South-Central, China SoutheastGBIF Backbone Taxonomy
Hardiness zones
5-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sunExtension Gardener Plant Toolbox
Soil pH
Acid (<6.0)Extension Gardener Plant Toolbox
Moisture
Good DrainageExtension Gardener Plant Toolbox

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Extension Gardener Plant Toolbox — NC State Extension; Plants of the World Online — Royal Botanic Gardens, Kew; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

  • Unusual among citrus for its deciduous, compound leaves and downy fruit. Being cold-hardy, it and its hybrids are widely used as citrus rootstocks. Wikipedia: Trifoliate orange
  • Mature trees grow in the gardens of St Paul's Cathedral in London. The cultivar 'Flying Dragon' has twisted stems and even stronger thorns. Wikipedia: Trifoliate orange

Protocol

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

  1. Clean the flesh off the seed

  2. Leach in running water

    Duration: 7 days

    Washed and cleaned daily for 7 days.

  3. Sow and cover

    Temperature: 70°F 21°C Light: dark

7 days from start to sowing. Then 28 days to germinate.

50% germination in 14–28 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Poncirus p. 196Public domain
Show the original text
Poncirus (Rutaceae). P. trifoliata seed was removed from the fruit and WC 7 d. This seed germ. 70D(50% in 2-4 w) and 70L(none). This is one of the few examples of photoinhibition that was found in the present work. The sample in 70L was shifted to 70D after 5 w whereupon it germ. as if the 70L period had not occurred. If the undersize seeds are discarded, the percent germination is 80-90%. Seed started at 40 or outdoors largely rotted.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Poncirus p. 196. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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