Buttonwood Bonsai Care [A Complete Overview]

Buttonwood bonsai care includes lots of sun and water. Tropical hobbyists grow their Conocarpus in as much sun as each yard allows. Vigorous growth begins in spring and continues through mid-summer. Conocarpus erectus (Combretum Family) is one of the most popular collected tropical trees for bonsai.

Conocarpus erectus – Photo by B. Hulnick

Watering

This plant likes water, but fungus and/or root rot can become a problem when planted in heavy soil. Coarse, fast-draining soil is best.

Temperature

Safeguard all your buttonwood bonsai from frost. They are tropical and will die if exposed to the normal winter weather of the United States. If it doesn’t kill them, it will burn the leaves, and you may have some residual damage, such as dead branches.

If you have small bonsai, bring them indoors when cold nights even threaten. Otherwise, place them under cover for protection. Even a cool night of 50 F (10 C) can cause a buttonwood bonsai to wilt, although it rarely causes damage.

Paul Pikel’s Buttonwood Bonsai on Cover of BCI magazine

Root Pruning and Repotting

Root pruning and timing are some of the most important parts of these buttonwood bonsai care notes.

Leaf Reduction

Conocarpus can be defoliated twice a year in the tropics with no problem. In other climates, there have been reports of dieback from complete defoliation.

Over time, full sun, root restriction, and regular pruning will also reduce leaf size.

Lots of twigging encourages smaller leaves, so prune frequently.

CAUTION:  Conocarpus roots are brittle at the point they connect to the trunk – and can break away easily.

It is not unusual for a collected specimen to have very few primary roots (sometimes only one!) There is often what looks like lots of root ramification. This can be a deceiving situation. Never ‘comb out’ buttonwood roots! Lightly hose off the old soil first … to determine what’s really going on.

Timing is very important. 

The best time to repot and/or root prune this plant is during the season of warmest nights. But, don’t wait too long. Allow the tree recovery time.

For example, in South Florida it’s better to root prune this tree during May, June or July, not late August. The tree then has time to re-establish new roots before an early (although improbable) cool spell.

In more tropical climates (e.g. the Caribbean) timing the root pruning is not such a problem. Outside of those tropical regions, timing is a serious consideration.

Buttonwood Bonsai Care During Tropical Dormancy

During the winter months, Conocarpus erectus has a natural “dormancy” period.

As with many tropicals, this dormancy is not necessarily one with fallen leaves. However, the leaves can become unattractive during this interval. This is not the time to try to make it look better.

While the tree is resting, additional branches are forming. These buds will explode into the new growth of spring. This new growth causes old leaves to drop; it is a natural process.

Another ‘slow down’ period for your buttonwood is in the heat of summer.  Again, it may not look 100%, but don’t encourage any special buttonwood bonsai care to make it better, let it rest.

Pests and Diseases

As with any dead wood, watch for borers and termites. “Sawdust” may be the first sign.

Old trees frequently have heavily textured bark … good hiding places for damaging bugs.

A wire brush is ideal for dead wood and cleaning the bark of buttonwood. At first, it may seem you are removing too much bark, but probably not. You may be pleasantly surprised at the new color and texture exposed from the brushing.

Buttonwood (with seed clusters)
growing in the rocks, Biscayne Bay, FL

The leaf-cutting bee and the citrus root weevil are two pests that can be more annoying than harmful.

(Citrus root weevils are often called “greenies” because of their pastel green color.)  Damage from both of these critters appears in the form of chewed leaves.

Moving your bonsai may be all that’s needed to discourage the leaf-cutting bee. Removing the difficult-to-see, pastel green beetle by hand will best take care of him. Neither of these pests arrives en masse.

If you have mites, aphids, or mealy bugs, the tree most likely needs more sun and/or better air circulation.

Also, make sure your buttonwood bonsai care includes fertilizing regularly. A healthy tree has fewer problems.

The leaves are particularly sensitive to chemicals … never use Malathion on this plant. If necessary, consider using a spray with pyrethrin or a soap-based product. (Even then, test spray an area first.)

Conocarpus e. Driftwood

Deadwood close-up

The  jin and shari of Conocarpus erectus trees are desirable as driftwood bonsai. Conocarpus driftwood is very hard (at one time used for buttons). The features can be enhanced by hard brushing and hand carving.

They can even be created with power tools.

It is difficult to replicate the inherent beauty of driftwood, but it can be done. Practice on throw-away pieces of wood first.

Buttonwood Deadwood Maintenance

To prevent rot, brush it, keep it clean and treat it with lime sulfur. (When possible, use lime sulfur outdoors; the smell resembles rotten eggs.)

Lime sulfur is available from most bonsai dealers.

Outside of the Tropics? Indoors?

Buttonwood bonsai care indoors can be a little tricky.

When grown in low light (not its favorite location), buttonwood is highly susceptible to scale insects, mealybugs, mites, etiolation (lengthening of space on stems between leaves) and large leaves.

Rather than fight these problems, move the tree into high artificial lightMany growers have experienced good results with fluorescent lights.

Water with warmish water. Water straight from the tap in winter may be too cold in winter. Another helpful tip for other tropical environments is: to use a propagation mat to keep the buttonwood’s feet warm.

Natural Environment

Buttonwood grows along the shoreline in Florida near the mangroves. Some mangroves have biologically adapted to grow in the water, while the Conocarpus e. (a close relative) prefers a little higher ground. They have endured years of windblown sand, tropical storms, hurricanes, droughts, and floods.

This amazing buttonwood, collected by Mary Madison, was named by bonsai expert John Naka.

The Florida Keys are the perfect place for such beauties to develop. Once you’ve seen a buttonwood bonsai, you may think all of them are gnarly, twisted, leaning trees full of dead wood. They’re not.

Aesthetic

Once you’ve seen a buttonwood bonsai, you may think all of them are gnarly, twisted, leaning trees full of dead wood. They’re not.

As bonsai, this tree almost always has beautiful driftwood.  Many of them are yamadori. Others have been carved to look like old trees. Buttonwood bonsai trees are often collected from the wild where they are most likely to have character and age.

They often have unique shapes and ‘driftwood’ trunks in a shoreline environment.

Some need a little help to gain the appearance of age. 

Collected trees can easily be carved to look like older trees.  The basic shape is there. The wood is very hard, and features can be created with both hand carving and power tools. It is difficult to replicate the inherent beauty of driftwood, but it can be done.  Practice on a throw-away piece of hardwood first.

Yamadori buttonwood with
no driftwood

Buttonwood Bonsai History

The buttonwood has attracted bonsai hobbyists since the 1950s. In the beginning, they were little more than plants in bonsai pots, but the driftwood expressed age even then. Sometimes the leaves were too big, and the overall appearance was rangy. 

Carl Rosner’s Indoor Buttonwood

Through years of experimenting and sharing knowledge, tropical artists have developed techniques for both better design and culture.  Some, such as Carl Rosner, have learned to grow it indoors!

Buttonwood Bonsai Tree Identification

Not sure if your tree is a buttonwood bonsai tree? The leaves can be quite different from one tree to the next. There are a couple of easier ways to tell.

The first way is always to identify it by the flower. Secondly, by two distinguishing glands – one on either side of the leaf stem (petiole).

Some say these petiole glands or “buttons” are where the common name originates.  Others insist the fruit with its round, compact, cone-like structure is the answer. An additional story credits the hardwood of Conocarpus, which made it valuable as wood for buttons in the late nineteenth century. This seems the most likely.

This chart of leaf sizes was created by Ed Trout.  Leaves were taken from many trees to show the varying sizes and shapes from plant to plant. 

National Champion

Every time I go to Key West, I make a point of stopping by for a visit.  I’ve seen it many times, and in 2008, I noticed a recently added plaque – ‘National Champion.’   Nice going, old tree!

This amazing ancient tree resides on the corner of Leon and Washington Streets in Key West, FL   It is estimated to be “hundreds of years old”.
This is a close-up of the gnarled trunk. The tree is located several blocks inland from the shoreline. It has been affected very little by the blowing of sand. No driftwood on this tree.

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