Germination Guide

Click on a species name below to see it's germination tips.
Search for a genus or species by entering specific words or parts of words.
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Iris sibirica 'Butter and Sugar'

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sibirica 'Ego'

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sibirica 'Shirley Pope'

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sibirica 'White Swirl'

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sibirica ex 'Outset'

*

This species needs special care as described.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

A

Sow @ 20°C. Seed germinates within 3 months.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sibirica hybrid

*

This species needs special care as described.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

A

Sow @ 20°C. Seed germinates within 3 months.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sintenisii

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris sp.

*

This species needs special care as described.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

G

Sow @ 4°C for 3 months, then place @ 20°C for 3 months.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris spuria

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris spuria hybrid

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed, prechill 4weeks,(or L) bring indoors once germinated to avoid temperature shock, transplant at 4 leaves
Iris spuria subsp. carthaliniae

*

This species needs special care as described.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris spuria v. halophila

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris suaveolens 'Rubromarginata'

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

*

This species needs special care as described.
sow fresh or soak old seed
Iris tectorum

*

This species needs special care as described.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

A

Sow @ 20°C. Seed germinates within 3 months.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris tectorum 'Alba'

*

This species needs special care as described.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

A

Sow @ 20°C. Seed germinates within 3 months.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris typhifolia

A

Sow @ 20°C. Seed germinates within 3 months.

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris unguicularis ssp. cretensis

C

Sow @ 20°C for 3 months, then place @ 4°C for 3 months.

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris variegata

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

6

Requires scarification. Nick or rub between sheets of sandpaper.  See https://youtu.be/icB9HrqdQqU  Seed coat of Baptisia and Oxytropis and other Fabaceae can be scarified by soaking in boiling water. See http://botanicallyinclined.org/continuing-the-sowing-in-hot-water

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

*

This species needs special care as described.
nick carefully; sow fresh or soak old seed; prechill 4 weeks, (or L), bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris versicolor

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris versicolor 'Blue Light'

*

This species needs special care as described.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris versicolor 'Mint Fresh'

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris vicaria 'Sina'

*

This species needs special care as described.

6

Requires scarification. Nick or rub between sheets of sandpaper.  See https://youtu.be/icB9HrqdQqU  Seed coat of Baptisia and Oxytropis and other Fabaceae can be scarified by soaking in boiling water. See http://botanicallyinclined.org/continuing-the-sowing-in-hot-water

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

Iris West Coast hybrid

*

This species needs special care as described.

H

Use repeated cycles of 4°C, then 20°C for 3 months each. Germination is very prolonged.
soak and rinse in clean water daily x 4 weeks
Iris willmottiana

*

This species needs special care as described.

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris winogradowii

*

This species needs special care as described.

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris x fulvala

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

*

This species needs special care as described.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Iris xiphioides

*

This species needs special care as described.

4

6

Requires scarification. Nick or rub between sheets of sandpaper.  See https://youtu.be/icB9HrqdQqU  Seed coat of Baptisia and Oxytropis and other Fabaceae can be scarified by soaking in boiling water. See http://botanicallyinclined.org/continuing-the-sowing-in-hot-water

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.
sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves
Isatis glauca

A

Sow @ 20°C. Seed germinates within 3 months.

2

Requires darkness.

*

This species needs special care as described.
germination better with seeds dried 2 years
Isatis indigotica

A

Sow @ 20°C. Seed germinates within 3 months.

N

Sow directly in garden.
Isatis sp.

A

Sow @ 20°C. Seed germinates within 3 months.
Isatis tinctoria

A

Sow @ 20°C. Seed germinates within 3 months.

2

Requires darkness.

*

This species needs special care as described.
germination better with seeds dried 2 years
Isolepis cernua

A

Sow @ 20°C. Seed germinates within 3 months.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

*

This species needs special care as described.
bog plant; stand pot in 3 cm water
Isophysis tasmanica

!

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

J

Sow @4°C for 3 weeks, then place @20°C.

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...
surface sow on peat; keep in pot 3 years
Isopyrum thalictroides

!

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.
Isotoma axillaris

A

Sow @ 20°C. Seed germinates within 3 months.
Itea virginica 'Little Henry'

3

Requires light or the small seeds should be surface sown. See https://www.youtube.com/watch?v=RgkXUSI1GWo&index=1&list=UUJfYCNSWCIuOB2...

A

Sow @ 20°C. Seed germinates within 3 months.
'Little Henry' is a dwarf selection. Seedlings will not necessarily retain dwarf characteristic.
Ixeris dentata v. alpicola

K

Sow @ 10°C. Most species for which we suggest this temperature will also germinate at 20°C, but prefer the cooler temperature for sturdy growth.
Ixeris dentata ssp. alpicola

K

Sow @ 10°C. Most species for which we suggest this temperature will also germinate at 20°C, but prefer the cooler temperature for sturdy growth.
Ixiolirion tataricum var. tataricum

F

Sow @ 4°C.
Ixiolirion pallasii

F

Sow @ 4°C.
Ixiolirion sp.

!

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

Ixiolirion tataricum

F

Sow @ 4°C.