Acer buergerianum

trident maple

The trident maple is a very popular species for bonsai, due to its small, three-lobed leaves, a readily-thickening trunk, and thick, gnarly roots which adapt well to root-over-rock style. A small tree, the trident maple usually grows only to 20 ft. in nature.

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Lighting:

 Tomlinson disagrees with Simon and Schuster: he believes this maple needs full sun; S&S recommends partial shade. This may have a lot to do with the environment of the tree in question; tridents in climates with extreme sunlight require shade.

Temperature:

 Although hardy in zones 5-8, the trident maple's roots have a high moisture content, and are susceptible to frost damage. This is a potentially fatal problem expereinced by members of the list/RAB and warned against in almost every book. Tomlinson goes so far as to suggest the substitution of Acer ginnala, the Amur maple, in colder areas. At the very least, this tree should be carefully winter protected.

Watering:

 Moderately in summer, easing off in winter. One poster remarked that tridents seem to get along fine in a climate with much rain.

Feeding:

 Tomlinson, as he usually does, suggests an aggressive feeding schedule: once weekly for the first month after leaves appear, then every two weeks during growth. S&S recommends feeding every three weeks during growth, with an interval in midsummer. I've used the more conservative schedule with my tree and have been happy with its growth, but find it entirely possible that more frequent feeding would improve the vigor of the tree. More frequent feeding, however, requires increased vigilance in pinching back. If a liquid fertilizer is used, it should not be sprayed on the leaves, as this may result in leaf burn.

Repotting:

 In spring, before bud burst. Roots grow very quickly, so annual repotting may be necessary for young trees; older trees tend to need repotting every 2-3 years. If root die-back has occured during the winter, trim off old root matter to allow room for new growth. Tomlinson recommends a fast-draining soil mix; I've had success with a standard bonsai soil.

Styling:

 Pinch back new growth to the first two leaves. The tree may be wired at any time during growth, but the branches are somewhat brittle and it is also wise to provide some protection for the bark. The tree, given ample pot space, will grow rapidly, so it is essential to continually check the wire to avoid scarring. Leaf pruning can be carried out in midsummer to miniaturize foliage. Make certain that the tree is healthy and vigorous before leaf pruning. Total leaf pruning should not be carried out annually, as the tree needs a year to restore its stores of energy. I've been told that it's safer to leaf prune gradually, removing only 1/3 to 1/2 of the tree's largest leaves at a time. The trident's leaves reduce readily, but it is more difficult to get short internodes and finely ramified branches. For the more advanced/courageous among us, Brent Walston suggests:
    For smaller pieces, in one gallon training pots, I let them grow wild for 2 or 3 years until the roots completely fill the pot and there is a noticeable decline in vigor. Theinternodes shorten and the leaves get smaller. It is at this point that I do major pruning shortening them to under a foot. The depleted state of the roots due to the rootbound conditions prevents them from forming the typical coarse growth that usually results following such a pruning. Performing this operation in summer will have an even more dramatic effect, since in essence it is a radical (very radical) defoliation. Root pruning and repotting can take place at the same time. As Michael would say, these are not procedures for beginners. Once there are potted up and the final branches are selected several defoliations a season will result in the short internodes and small leaves so desired.

Propagation:

 Trident maple can be grown from seed, air-layered, or grown from both hardwood and softwood cuttings. Tomlinson says that even wrist thick cuttings may take, and one instance of a six-inch (!) cutting being rooted successfully has been reported. Best results are achieved taking cuttings in late winter-early spring for hardwood and midsummer for softwood. Seeds require a 24 hour hot water soak, then cold-moist pretreatment for three months. Seeds need to be stored refrigerated, which will start the cold- treatment process. Seeds kept in dry storage are tough to activate, resulting in a poor percentage of germination. If you cannot collect your own seed, it seems that purchasing fresh, properly stored seed from a reputable dealer is essential.

Pests etc.:

 As with other maples, tridents seem to be sensitive to leaf burn. Tridents are also vulnerable to caterpillar attack.

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Date:         Tue, 26 Mar 1996 07:20:48 -0600
Reply-To:     Internet Bonsai Club 
Sender:       Internet Bonsai Club 
From:         "David S. Crighton" 
Subject:      T.Maple hardiness (was Re: Tree of the Week Acer..)
Comments: To: steve wachs 
In-Reply-To:  <199603260059.SAA06906@orions0.orion.org>

On Mon, 25 Mar 1996, steve wachs wrote:

> mongo snip<

Speaking of which...I don't care for (gentle wording) the new tag lines.

>  i would like to grow trident maples, but my problem is wintering them.
>  if leave them outside until right before it freezes can i bring them
> indoors for the winter?
>   the only ones i have seen on long island  are those kept in a  greenhouse
> that is cold in the winter, but does not go below freezing.  thanks

Steve,

I have Tridents in the ground.  It consistently gets below freezing
during the winter.  Actually, consistently is not right.  Our winter
fluctuate wildly.  Lows of 10 F one night and 35 F the next.

My tridents do fine in the ground.  I can't speak for potted tridents
yet, but I would bet that given some protection from the wind and a
little root insulation, they'd do fine.

BTW, where are you?  You might add that to your sig. line.

I have some in the ground I'd be willing to trade if you're interested.

David

I B N Springfield, Missouri...TOO close to Branson.

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Date:         Thu, 28 Mar 1996 18:14:19 -0500
Reply-To:     Internet Bonsai Club 
Sender:       Internet Bonsai Club 
From:         AndyWalsh@AOL.COM
Subject:      Re: T.Maple hardiness (was Re: Tree of the Week Acer..)

In a message dated 96-03-26 08:21:46 EST, Dave responds to Steve Wachs:

> I can't speak for potted tridents
>yet, but I would bet that given some protection from the wind and a
>little root insulation, they'd do fine.

Hi

Tridents definitely need more winter protection than average for the New York
metropolitan area. I too have grown Tridents in the ground quite easily. I
have two in the ground right now that I'm planning to take several
airlayerings from this year. I planted them two years ago and they are now
over 10 ft tall.

I had two Tridents in the ground for 5 years. I root pruned them in the
ground and rough trained them there. They grew like weeds. One was especially
nice and already had a beautiful root structure. I dug them up and potted
them. They were fine all summer but in the spring they were dead. I blamed it
on root rot and a bad choice of soil but now I know that the typical cold
winter temperatures we experience in New Jersey killed their roots.

I have a Trident growing over a rock that was planted the same time as the
two mentioned above. This tree I kept in the ground for 7 years. I
subsequently read that Trident roots were temperature sensitive so I was very
careful with this tree. I now winter this tree in my basement in a cold (down
to 40F) closet. This tree is doing fine.

So, my advice is to find a spot that does not get very cold or can be
controlled that you can winter your Tridents in. Otherwise you may be
brokenhearted soon.

Andy
Central NJ

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Date: Thu, 11 Apr 1996 12:37:11 -0700 (PDT)
From: John Yasaki 

On Wed, 10 Apr 1996, Robert F Caine wrote:

> Will a more aggressive feeding schedule imporve the vigor of the
> tree, or damage it?

Probably make it so you have to pinch a little more; that's about it.

> I've heard that some maple seeds need to be planted almost
> immediately, and therefore do not store well.  Is this true of
> trident maple?

Trident seeds can be stored, however, they must then be revived prior to 
sowing. F.W. Schumacher Co. suggests the following: 

Take the (dry) seeds to be sown, an dplace them in a bowl or cup. Pour 
near-boiling water over them. Allow to cool/soak for at least 24 hours. 
Cold stratify for 3 months, then sow. The guy there said he uses water 
run through his Mr. Coffee. I used boiled water which had cooled about 5 
min in the kettle. Seemed to work OK.

> Are there any tricks to styling the trident maple root-over-
> rock?  Also, since the trident maple is so sensitive to frost,
> how do you protect exposed roots in the winter?

Exposed roots are not roots. Once you get the desired thickness and have 
them uncovered, they're a trunk which is wrapped around (or over) a rock. 
Tricks? Not really. Encourage long roots, tie or wrap them around the 
rock with some soft material (cotton twine, floral tape, gauze, 
cheesecloth, etc), and plant for a long, long time. Using a coarse mix 
toward the soil surface and a finer mix below may help the actual feeding 
part of the root system develop lower, while encouraging the upper (rock 
wrapping) roots to thicken. John Uchida had a few imported from Japan; 
the trees were 4-6 inches tall, and reportedly had been in the ground for 
something like 10 years.

> Lighting: Tomlinson disagrees with Simon and Schuster: he
> believes this maple needs full sun, S&S recommends partial shade.

Depends on location. In Calif, in summer, full sun will fry the leaves. 
They do seem to take sun better than A. palmatum, however.

> Tomlinson goes so far as to suggest the substitution of Acer
> ginnala, the Amur maple, in colder areas.  At the very least,
> this tree should be carefully winter protected.

Amurs have somewhat larger leaves, and, if I remember correctly, will not 
ramify as well as trident. But, if you can't do trident due to 
environmental reasons, why not?..

> Styling:  Pinch back new growth to the first two leaves.  The
> tree may be wired at any time during growth, but the branches are
> somewhat brittle and it is also wise to provide some protection for
> the bark.

Make that a lot of protection for the bark. Also, watch carefully; they 
thicken pretty damn fast in spring, so be careful.

> Propagation: Trident maple can be grown from seed, air-layered,
> or grown from both hardwood and softwood cuttings.  Tomlinson
> says that even wrist thick cuttings may take (!) and recommends
> late winter-early spring for hardwood and midsummer for softwood.
> Seeds usually germinate in the fall, but may need some frost
> protection.

There was an issue of BT in which a 6 inch (?) trunk cutting was struck 
successfully. (At least partially successfully, anyways.) Don't remember 
the issue number.


john yasaki
Yamato Bonsai Club
Hayward, CA

Rantings expressed may be reprinted as desired.

=================================================================

From: Craig@Triumf.Ca (Craig J. Hunt)

Hi Sabrina, you wrote;

>Here is my pathetic summation of the trident maple.  Although I
>have a trident maple, I've only had it for two years, barely
>time to get my sea legs.

I've had mine 3 years, and can add a few points:

Tridents are sensitive to what is sprayed on their leaves, I burnt mine 
using a water based fertilizer similar (?) to superthrive.

We have a little catilpillar that love trident maple leaves. I have to keep 
an eagle out for them, they can clean off my tree in no time.

If you put them in a slow pot to early, trunk growth virtually stops.

>Watering: Moderately in summer, easing off in winter.

Due to my location, (Vancouver) my tridents get a lot of water (rain) in the 
winter and don't seem to have a problem.

>Styling:  Pinch back new growth to the first two leaves.  The
>tree may be wired at any time during growth, but the branches are
>somewhat brittle and it is also wise to provide some protection for
>the bark.  Leaf pruning can be carried out in midsummer to
>miniaturize foliage.  Make certain that the tree is healthy and
>vigorous before leaf pruning.  Total leaf pruning should not be
>carried out annually, as the tree needs a year to restore its
>stores of energy.  I've been told that it's safer to leaf prune
>gradually, removing only 1/3 to 1/2 of the tree's largest leaves
>at a time.

Leaf size seems easy to reduce.

I hope this helps.

Craig J. Hunt in Vancouver, B.C., Canada
   http://ATG.Triumf.Ca/Craig/Craig.htm

=================================================================

Date: Thu, 11 Apr 1996 21:25:08 -0700
Sender: Internet Bonsai Club 
From: Brent Walston 

There is no problem storing Trident Maple seed as long as it is refrigerated
at 30 to 40 degrees and the seed is not overly dried. It is this extreme
dessication of maple seed that seems to be the problem. Best germination
occurs with 3 months of cold moist pretreatment at 40 degrees.

There are some really interesting cultivars of A. buergeranum. I am just
beginning to get into them. There is 'Naruta Kaede', which has leaves that
up turned at the edges, almost rolled, that give it a very sharp 3 pointed
look. This is a very vigourous plant and seems to grow faster that the
species, producing big trunks in a short period of time. 'Mino Yatsubusa' is
a semi-dwarf with peeling bark, Miyasama Kaede Yatsubusa is a stubby
congested form with very short internodes. 'Goshiki Kaede' is is white
variegated, 'Tancho' is a dwarf form with rolled edges like 'Naruto Kaede'.
This year we introduced  a rough bark cultivar from a chance seedling and
named it 'Evergreen's Rough Bark', it has hawthorn-like scaly bark.

Most of the show pieces on A. buergeranum are monster trunk specimen, but it
can make excellent Shohin as well. The problem I see with Trident and most
of the maples for that matter is how to obtain close internodes and refined
twiggy branching from plants that want to throw five foot whips in a single
season. I am attacking that problem now. For smaller pieces, in one gallon
training pots, I let them grow wild for 2 or 3 years until the roots
completely fill the pot and there is a noticeable decline in vigor. The
internodes shorten and the leaves get smaller. It is at this point that I do
major pruning shortening them to under a foot. The depleted state of the
roots due to the rootbound conditions prevents them from forming the typical
coarse growth that usually results following such a pruning. Performing this
operation in summer will have an even more dramatic effect, since in essence
it is a radical (very radical) defoliation. Root pruning and repotting can
take place at the same time. As Michael would say, these are not procedures
for beginners. Once there are potted up and the final branches are selected
several defoliations a season will result in the short internodes and small
leaves so desired.

Brent
Evergreen Gardenworks
=================================================================

Date: Fri, 12 Apr 1996 08:04:49 -0700
Sender: Internet Bonsai Club 
From: Brent Walston 

At 05:15 AM 4/12/96 -0400, you wrote:
>In a message dated 96-04-11 02:30:56 EDT, you write:
>
>>I've heard that some maple seeds need to be planted almost
>>immediately, and therefore do not store well.  Is this true of
>>trident maple?
>
>It is my understanding that maples whose seeds mature in the spring should be
>planted immediately, and that those that mature in the fall are stratified.
> In both cases the seeds should not be allowed to dry out during any kind of
>storage.
>
>Jim Thomas (Da Yooper)
>

Jim

This is absolutely correct. Red Maple, Acer rubrum, must be planted
immediately before the seed begins to dry out. Germination is in about 10
days. Any attempt to dry and store the seed will fail. Do not buy A. rubrum
seed (many companies sell it), it will not germinate unless it is absolutely
fresh and I know of no companies that will do this. Reputable firms will not
handle it.

Other maple seed can be stored if refrigerated before it dries out, but this
will start the pretreatment and the breakdown of the germination inhibitors,
so at best it can be stored for 3 months. Stored dry seed can be kept
longer, but reviving it can be exceedingly difficult and the results spotty.

Brent
Evergreen Gardenworks
=================================================================





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Information Sources:

Any bonsai book worth purchasing that contains a species guide will have an entry on trident maple. My information cames from Tomlinson's "Complete Book of Bonsai" and the "Simon and Schuster Guide," with some additional help from posts and e-mail by David S.Crighton, Steve Wachs, Andy Walsh, John Yasaki, Craig Hunt, Brent Walston and Jim Thomas.


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