How to Grow Japanese Maples from Seed

 

It looks easier as it is, in fact growing Japanese maples from seed isn't an easy task. It is only possible if you are willing to invest time and some patience. In other words, it's not mission impossible if you follow these steps:

The ASIAN maple species method

1. Vine maple, striped maple, Amur maple, and paperbark maple are all tough to germinate and require extra attention. This applies to most other species native to Asia, as well as mountain maples and rocky mountain maples. All of the seeds in this category drop in autumn or winter. Left alone in the soil, they can take years to germinate.

2. Treat the outer hull. Many of these species have an extremely hard hull (pericarp). Growers often "scarify" the hull to greatly improve germination rates. You may use any of these methods: Rub the base of the seed (opposite the wing) against a nail file or sandpaper. 

• Stop as soon as you break through the hull, barely nicking the seed coat underneath.
• Soak the seeds in household-strength hydrogen peroxide for several hours, then rinse well.
• Soak the seeds in warm water for 24 hours

3. Store in a warm room. The US Forest Service recommends keeping the seeds at 20–30ºC (68–86ºF) for 30–60 days. These seeds have not been studied as thoroughly as those of other species, so exact guidelines for each species are not available.

Now, if you've been waiting 60 days, it's half the way to success. Don't give up at this point and follow the remaining steps. 

4. Cold stratify for 90–180 days. Transfer the seeds to a plastic, zip-locked bag in the refrigerator, with a small handful of peat moss or other growing material. Check back every couple of weeks to look for signs of mold, drying, or sprouting. 

Rocky mountain seeds (Acer glabrum) usually take the full 180 days to germinate. Other species can take as few as 90, but they are unpredictable. Don't expect every seed to sprout. Germination rates as low as 20% are common for these species.

5. Plant the seeds. You may start the germinated seeds on an indoor seedling tray, or plant them outside if the last frost has passed. Plant them 0.6 to 2.5cm (¼ to 1 inch) beneath the soil surface. 

Water occasionally but deeply, not letting the soil stay dry for long. For more specific information, look up your exact maple species.

If this method doesn't work for you. You may want to try a different method which is the direct germinating in the soil method. These are the five steps:

The direct planting (germinating) in the soil method

1. Collect seeds in late spring or early summer. Silver maples and some red maples (but not Japanese red maples) will drop their seeds early in the growing season. These species do not go dormant, and there is no need for any special treatments.

2. Plant immediately. Seeds of this type will die if they dry out in storage. Plant shortly after you collect them. They should germinate quickly.

3. Plant on moist ground. Place the seeds on the moist ground with plenty of leaf litter and other organic material. As long as the soil doesn't dry out, the seeds will require no maintenance.

4. Plant in sun or partial shade. Silver maples grow poorly in the shade. Red maples can handle shade for 3–5 years but may have trouble growing if they remain under the canopy past that point.

5. Leave bare seedbeds undisturbed (optional). If some of the seeds fail to germinate, they will often sprout the following year. These are usually a minority of the seeds, but if you haven't had much success it could be worth leaving the area untended for a second season.

If very few of the seeds germinate, and the climate has been fairly typical, the seeds most likely died in storage. Plant a new batch next year rather than wait.

The most common method is stratification

1. Try this for most maple seeds. Sugar maples, bigleaf maples, boxelder maples, Japanese maples, Norway maples, and some red maples lie dormant over the winter, then germinate as soon as temperatures warm. The cold stratification approach produces very high germination rates in these species. 

All of these species drop their seeds in autumn or early winter. If your red maple trees drop their seeds in spring or early summer, try germinating them in the soil instead.

If you're going to plant the seeds outdoors, start this method 90–120 days before the last winter frost.

2. Fill a plastic bag with growing material. Place a handful of peat moss, vermiculite, or germination paper in a small, plastic, zip-locked bag. For best results, use sterile material and handle it with disposable gloves to avoid introducing fungus.

Tiny "snack-sized" bags work best. Larger bags trap more air with the seeds, which can lead to fungal problems.

Red maple seeds are sensitive to acidity. For this species, choose vermiculite (a neutral or basic substance) rather than peat moss (acidic).

3. Add a little water. Add a couple drops of water to the growing material to dampen the material slightly. If you see standing water, or if you can squeeze out water from the material, it is too wet.

4. Optionally, you can apply a little fungicide. Fungicide can prevent mold from destroying your seeds, but it is not always necessary and may damage the plant if overused. Add only in tiny quantities, following the manufacturer's instructions. Some growers rinse the seeds in very diluted bleach solutions instead.

5. Add the seeds and close the bag. Place your seeds in the bag. Starting from the base, roll the bag to expel most of the air. Zip it closed.

6. Store in the refrigerator. Now it's time to "stratify" the seeds, or expose them to temperatures that trigger germination. For most species, the ideal temperature is usually around 1–5ºC (33.8–41ºF). The crisper drawer of a refrigerator is usually about this temperature. 

Ideally, use a thermometer to confirm the correct temperature. Some seeds may fail to germinate if the temperature is just a couple degrees off.

If possible, keep boxelder and Norway maple seeds at exactly 5ºC (41ºF), and red maple seeds at exactly 3ºC (37.4ºF). Other species are not as picky.

7. Leave them for 40–120 days, checking every week or 2. Most of these species take 90–120 days to germinate, but the bigleaf maple and a few others can sprout in as few as 40. Every week or 2, check on the bag and make adjustments as needed: If you notice condensation, pick up the bag and gently tap it to knock the water droplets off. Lay the bag back down on the opposite side, so the wet seeds have a chance to dry off.

• If the growing material has dried out, add a drop or 2 of water.
  
  
• If you notice any mold or black spots, remove the affected seed and throw it away. (If the whole batch is molding, try a little fungicide.)
  
  
• If the seeds have begun to sprout, remove them from the refrigerator.

8. Plant the seeds. Once the seeds have germinated, plant them 0.6–1.2cm (¼–½ inch) under moist soil. Most maples do well in partial shade but look up the exact species if possible for more info on planting.

To increase the odds of survival, start the seedlings in an indoor seed tray instead. Fill the tray with 7.6–10 cm (3–4 inches) of well-draining potting soil, or an even mix of peat moss, rotted compost, vermiculite, and coarse sand. Water whenever the soil becomes completely dry. Transfer to planter pots once the second set of leaves appears.

The World of Japanese Maples

• Coonara Pygmy

  In spring, this dwarf Japanese maple unveils its pink-tinged leaves. The pink tinge fades in summer, but then in fall the Japanese maple leaves turns a brilliant shade of orange-red. Because of its small size, this maple is well-suited to containers.

  Name: Acer palmatum 'Coonara Pygmy'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 8 feet tall and wide

  Zones: 6-8

  Choose It Because: You need a Japanese maple for a container or for a small space.

  • Find more tips for growing Japanese maple trees.
• Green Cascade

  This fullmoon Japanese maple offers lustrous, finely cut green foliage and a delicate weeping habit. If not staked, it forms a flowing mound of foliage. In fall, the Japanese maple leaves turn shades of red and orange.

  Name: Acer japonicum 'Green Cascade'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: Groundcover to 10 feet or more

  Zones: 5-7

  Choose It Because: You need a good weeping variety.

• Autumn Moon

  Like the golden fullmoon Japanese maple, this Japanese maple features golden leaves. But on this variety, the leaves bear decidedly pink tones. In fall, these Japanese maple leaves put on a show in shades of red, orange, and yellow.

  Name: Acer shirasawanum 'Autumn Moon'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 25 feet tall and wide

  Zones:5-7

  Choose It Because: You need a Japanese maple with golden leaves.
• Hogyoku

  A great time-tested selection, this mid-sized Japanese maple tree bears rich-green leaves that turn bright orange in autumn. It's sturdy and tolerates heat better than many other varieties.

  Name: Acer palmatum 'Hogyoku'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 15 feet tall and wide

  Zones: 6-9

  Choose It Because: You need a variety that's heat tolerant.
• Golden Fullmoon Maple

  An exceptionally beautiful plant, this Japanese maple tree features golden-yellow leaves through the summer. In fall, the leaf tips develop red edges while the leaf center stays golden.

  Name: Acer shirasawanum 'Aureum'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 20 feet tall and wide

  Zones: 5-7

  Choose It Because: You need a Japanese maple with golden foliage.
• Beni Kawa

  A tree for all seasons, this Japanese maple features small green leaves that turn golden-yellow in fall. In winter, the plant really shines because of its clear-red stems. They look stunning against a backdrop of snow.

  Name: Acer palmatum 'Beni kawa'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 15 feet tall, 12 feet wide

  Zones: 6-9

  Choose It Because: You want winter interest.
• Higasayama

  A favorite for bonsai, this dwarf Japanese maple tree offers pink buds that open into leaves colored in cream, green, and fuchsia. As the season progresses, the Japanese maple leaves fade to green, then change to glowing shades of gold and yellow in autumn.

  Name: Acer palmatum 'Higasayama'

  Growing conditions: Part shade and moist, well-drained soil

  Size: 15 feet tall and wide

  Zones: 6-8

  Choose It Because: You enjoy variegated foliage.
• Emperor 1

  A favorite because of its dark purple-red foliage, the Japanese maple tree Emperor 1 is also a good choice for northern gardens as its leaves open a bit later than most -- helping it avoid late spring frosts. It also offers brilliant scarlet-red fall color.

  Name: Acer palmatum 'Wolff'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 15 feet tall and wide

  Zones:5-8

  Choose It Because: You want a good red-leaf type or live in the North.
• Coral Bark

  A good-sized Japanese maple tree with multi-season appeal, 'Sango-kaku' features green leaves that turn brilliant yellow in fall. After the leaves drop, the stems show off a bright coral-red color.

  Name: Acer palmatum 'Sango-kaku'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 20 feet tall and 15 feet wide

  Zones: 6-8

  Choose It Because: You want winter interest.
• Sumi Nagashi

  This big red Japanese maple tree variety offers deeply cut leaves and rich, purple-red foliage that looks good all spring and summer. In fall, the graceful leaves turn bright crimson.

  Name: Acer palmatum 'Sumi nagashi'

  Growing Conditions: Part shade and moist, well-drained soil

  Size:18 feet tall and wide

  Zones: 5-8

  Choose It Because: You want a big red cut-leaf variety.
• Bloodgood

  A classic, the Japanese maple 'Bloodgood' offers deeply cut, purple-red leaves that hold their color well through the summer. Then in fall the tree develops striking crimson-red color.

  Name: Acer palmatum 'Bloodgood'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 20 feet tall and wide

  Zones: 6-8

  Choose It Because You want a time-tested big red cut-leaf variety.
• Villa Taranto

  This eye-catching variety of Japanese maple tree offers deeply cut, spidery leaves that emerge pink in spring, then fade to bright green in summer. In autumn the leaves again change -- this time to beautiful golden yellow.

  Name: Acer palmatum 'Villa Taranto'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 10 feet tall and wide

  Zones: 6-8

  Choose It Because You want a small cut-leaf variety.
• Crimson Queen

  This stunning variety of Japanese maple offers weeping branches of beautiful crimson-purple foliage. In autumn, the finely cut leaves turn bright crimson.

  Name: Acer palmatum 'Crimson Queen'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 12 feet tall and wide

  Zones: 5-8

  Choose It Because: You want a weeping red cut-leaf variety.
• Beni Schichihenge

  A smaller Japanese maple tree, this stunning variety offers blue-green leaves variegated in shades of pink and cream. In fall, they change to exciting shades of orange and gold. It also tends to resist leaf scorch from hot, dry weather better than many varieties.

  Name: Acer palmatum 'Beni schichihenge'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 8 feet tall and wide

  Zones: 6-9

  Choose It Because: You want variegated foliage or a heat-resistant variety.
• Aconitifolium

  We think this is one of the most beautiful Japanese maples. It offers deeply cut, almost ferny foliage that opens to green and turns shades of red, orange, and yellow in fall.

  Name: Acer japonicum 'Aconitifolium' (also called 'Maiku jaku')

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 10 feet tall and wide

  Zones: 5-8

  Choose It Because: You need a cut-leaf Japanese maple with a great texture.
• Caperci Dwarf

  This small, slow-growing Japanese maple tree offers pink-tinged new growth that fades to green as the season progresses. Then in fall, the green leaves turn a nice shade of warm, glowing gold.

  Name: Acer palmatum 'Caperci Dwarf'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 6 feet tall; 10 or more feet wide

  Zones: 6-8

  Choose It Because: You need a Japanese maple for a container or for a small space.
• Vitifolium

  A big, sturdy Japanese maple tree, this variety offers wide, deep green leaves that turn bright shades of gold, yellow, orange, and scarlet in autumn.

  Name: Acer japonicum 'Vitifolium'

  Growing Conditions: Part shade and moist, well-drained soil

  Size: 25 feet tall and wide

  Zones: 5-9

  Choose It Because You need a Japanese maple that tolerates cold or warm weather well.
• • Dissectum Atropurpureum

    This classic Japanese maple variety bears deeply cut, feathery red-purple leaves that turn bright crimson in fall. We also love its graceful, weeping habit.

    Name: Acer palmatum 'Dissectum Atropurpureum'

    Growing Conditions: Part shade and moist, well-drained soil

    Size: 8 feet tall and wide

    Zones: 6-9

    Choose It Because: You want a good, small-size red cut-leaf variety.

    • Learn more about Japanese maples!

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