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Yucca filamentosa

Adam's Needle · Bear Grass · Needle-palm

Family AsparagaceaeGenus Yucca

A tall spike of cream bell flowers beside a brick wall
FlowerSten at Danish WikipediaCC BY-SA 3.0

About the plant

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

The plant

Habit
Broadleaf evergreenPlant Finder
Habit
perennialPlants of the World Online
Height
4-8 ft1.2-2.4 mPlant Finder
Spread
2-3 ft60-90 cmPlant Finder
Flower
Showy; creamy whitePlant Finder
Blooms
June to JulyPlant Finder
Native range
Central and eastern United StatesPlant Finder
Hardiness zones
5-10Plant Finder
Note
Seed can be collected October to March: it sits in upright capsules over winter, and that is as good as dry storage.Seed Germination Theory and Practice, 2nd ed.

Growing conditions

Sun
Full sunPlant Finder
Soil
Light, dry to medium, well-drained; tolerates poor sandy soilPlant Finder
Soil pH
Neutral (6.0-8.0)Extension Gardener Plant Toolbox
Moisture
Good Drainage, Moist, Occasionally DryExtension Gardener Plant Toolbox
Watering
Dry to mediumPlant Finder

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

Sources: Plant Finder — Missouri Botanical Garden; Plants of the World Online — Royal Botanic Gardens, Kew; Extension Gardener Plant Toolbox — NC State Extension; Seed Germination Theory and Practice, 2nd ed. — N. C. Deno.

Worth knowing

  • Yuccas and the yucca moth depend on each other. The female moth carries pollen from flower to flower and lays her eggs in the ovary; the larvae eat some of the developing seeds, and the rest survive to be scattered. Lady Bird Johnson Wildflower Center: Yucca filamentosa

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around June 19, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on June 18, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    11% came up here. Deno gives no length for this period; three months is his standard cycle.

  3. Warm moist stratification

    Temperature: 70°F 21°C

    A further 85%.

about 9 months from start to step 3. Germination happens during step 3; time not stated, 21 days assumed.

85% germination.

11% in the cold and 85% after the move: first up on the second day, then half of what is left every two days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, YuccaPublic domain
Show the original text
Yucca (Liliaceae). V. filamentosa seed can be collected from October to March as the seed is held in the upright capsules through most of the'winter. Germination is increased by DS. Seed DS 6 m at 70 or 40 germ. 70(57%, i. t 2 d, first order rate, half time 20 d)-40-70(43%, ind. t 2 d, first order rate; half time 1-2 d) and 40(11%)-70(85%, ind. t 2 d, first order rate, half time 2 d). Note the much faster rate of germination in a 70 cycle which was preceded by a 40 cycle. Fresh seed germ. at lower rates and lower percentages. Seed collected in March approached the higher rates and better germination of DS seed since overwintering outdoors in the seed capsule is equivalent to DS.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Yucca. 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.

Protocol 2

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Warm moist stratification

    Temperature: 70°F 21°C

    57%, first up on the second day, then half of what is left every twenty days.

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    Deno gives no length for this period; three months is his standard cycle.

  4. Warm moist stratification

    Temperature: 70°F 21°C

    A further 43%, and this time half of what is left every day or two.

Steps after step 2 run on after germination.

about 6 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

57% germination.

57% at 70, but half the packet only every twenty days. The 43% that follows a cold cycle arrives ten times faster -- which is Deno's point here.

This source doesn't state how long step 4 lasts.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, YuccaPublic domain
Show the original text
Yucca (Liliaceae). V. filamentosa seed can be collected from October to March as the seed is held in the upright capsules through most of the'winter. Germination is increased by DS. Seed DS 6 m at 70 or 40 germ. 70(57%, i. t 2 d, first order rate, half time 20 d)-40-70(43%, ind. t 2 d, first order rate; half time 1-2 d) and 40(11%)-70(85%, ind. t 2 d, first order rate, half time 2 d). Note the much faster rate of germination in a 70 cycle which was preceded by a 40 cycle. Fresh seed germ. at lower rates and lower percentages. Seed collected in March approached the higher rates and better germination of DS seed since overwintering outdoors in the seed capsule is equivalent to DS.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Yucca. 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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