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A General Guide to Pot Selection

A General Guide to Pot Selection

By Kenneth A. Schultz

Does the pot make the tree or does the tree make the pot? After all, bonsai means plant in a shallow pot. In my reading and in practice the pot is not the first consideration. Well, not always, I do have a collection of pots and occasionally I will look for the tree that will go into one of these pots. More commonly, I will be looking at a tree and wonder - do I have a pot for this?

To prepare this article, I riffled through my bonsai book collection to select the ones that have special tips and suggestions. What did I find? It was a mixed bag. Most books limited their discussion to a few short pages. And a number of them don’t discuss how to select a suitable pot for the type or style of tree to be planted. Rather their focus was on photographs of pots for sale, showing some store or factory. Others ignore the pot itself as a part of the artistic composition of bonsai, and talk about putting screen over the drain hole (eye) and advising to wire the tree into the pot.

So what is so special about picking a pot? Well, we have all heard the golden rules. Pines and Junipers in brown matte’ pots and deciduous and flowering trees in glazed color pots. But there is more to picking a pot than just that, and sometimes these rules might need to be ignored. Besides there is the whole issue of selecting the shape of the pot based on the growth style of the bonsai. Author and artist Amy Lang captures the importance of the pot stating that it allows the viewer to imagine the tree growing in its natural element. There are three elements to the art of the bonsai composition; the tree, the pot and the position of the tree in its pot.

Generally when you are pot shopping, avoid pots that rock on flat surfaces. Pots with chips or cracks are only for growing, not showing. There should be a number of eyes, or drain holes, at the lowest point of the pot’s bottom. Pots that have low points that don’t drain may cause root rot.

And “ping” the pot. Pots that are fired longer will have a “ring” rather than a thud or clunk when struck. Test them by wetting your finger and then rubbing it in the inside of the pot. If the clay readily absorbs the moisture, it may be low fired. Glazed pots that are low-fired pots will crack, and spaul, and the glaze will come off in flakes.

Inward curing shapes or an edge on the inside of the upper rim should only be used with your indoor trees. In the winter, when the root ball freezes, it will catch under these rims and crack your pots. For growing outdoor trees you may want to use mica pots.

Here’s what some of the authors had to say about color:
What Color Should I Choose? What do the “experts” say? Most evergreens and conifers are best in brown containers. Glazed and matte’ finishes may be used for any species. Arid species are best in unglazed pots. Earthen brown pots – matte’ or unglazed with sides curving outward are ideal for evergreens; especially those with slender curving trunks.

Colored containers pose a host of possibilities. White can be used for broadleaved specimens, deciduous trees that fruit, flower or having bright fall leaf color. The color needs to compliment the tree’s flowers, fruit, bark or fall foliage. Dark colors are and should be used with bonsai that exhibit “strong character” (massive nabari in proportion to height, or formal upright). The use of decorated or multi colored pots should be limited to truly spectacular bonsai to keep the pot from taking more attention than the tree. With mame’ brightly colored pots can be used as the enthusiast wants.

Light colors stay cooler. Remember this if your trees are in a sunny spot. Dark brown pots may actually get hot enough to bake roots that touch the pot. Also unglazed matte’ pots absorb more heat. Your pines and junipers could need more water than your trees in light colored glazed pots on the same day.

Reddish pots look wild and strong, they can express rocky mountains or barren land.

Blue pots represent water. Subtle blue is a good color for azaleas or quince. I have seen many maples pictured in light blue pots. Dark blues are for plants with light colored leaves or flowers. Cobalt blue glazed rectangular pots are good for trees with red fall color or berries. Cotoneaster is mentioned as a good choice for cobalt blue, but avoid putting plants with blue flowers in blue pots.

Cream colored pots are recommended for elms and maples. At Franklin Park we have also used them for ficus. Beige stoneware (matte’) pots are good with stout trunked conifers, oak, cork bark and hemlock.

Grey greens are for broadleaved plants and larch. The green color reminds one of a meadow.

Yellowish colored pots are for fall scenes and trees that turn golden yellow. While no species was suggested, I know that gingko put on a very yellow fall display. Mustard colors (with scenes) show well with figs, schefflera, tea and jasmine according to Gustafson.

Container Size:
Here again there are golden rules that govern a ratio of pot size to tree size. Most of us as Gustafson suggests, should ignore these rules for the reason stated in the next paragraph. But first the ratio: Length should equal 2/3 the tree’s height. Depth should equal the diameter of the trunk on a mature bonsai (don’t count the leg or foot height). Width should be slightly narrower than the tree’s spread – as seen from the side.

Size may be ignored when using rocks and other decorations or for allowing growth or with certain species that need more water. Following the rules could result in a plant that needs to be watered four times a day. I know that I’ve over-potted a number of my trees because I only have time to water once a day. Consider the volume of soil held in the pot based on its height, curve and legs. Remember that smaller pots freeze quicker too; as do pots with longer legs. While these feet are needed for air and drainage they can aide in drying and freezing.

Container Shape based on Tree Style:
If you have antique pots you should save them for “very old” trees. Younger trees are OK in new pots. Again the shape of the pots also has associated locations. Deep pots suggest cliffs making them suitable for cascades. Semi-deep pots suggest hillocks suitable for slanting styled trees, and shallow pots represent plaines. They should be used for upright trees or group plantings.

Square or rectangular pots - high mountains, angular trees or strong imposing trees. Generally trees in square or rectangular pots are formal or informal upright style including slanting. “Heavy trees” need massive pots. Heavy rectangular pots frequently have conifers, that have gin and shari. “Formal” groves and clumps may also be planted in rectangular pots.

Cascade Pots – round, square, hexagonal. The pot should be taller than its distance across. The height of the pot should be greater or less than the length of the cascade, not the same. However the depth of the pot should be greater than the height of the tree above the pot. A stand should be used if the tree extends below the bottom of the pot

Oval or round – represent river or lakesides, curved trunk trees or “softer styles”. Oval glazed pots are for deciduous trees, mame’ or shohin sizes. Chinese elm, pomegranate, serrisa and miniature rose are species suggested for oval glazed pots. Shallow oval glazed pots are used for group plantings. Broom style is also recommended for oval but look best in round. “Delicate” fine pots (porcelain like) are best with twiggy trees like apricots, pistachios, plums and dwarf citrus. These also look good in round pots with a deep blue glaze. Windswept or slanting style trees should be planted in oval pots. Their oval pots are longer, narrower or smaller than normal.

Round “drum” style pots have literati, formal or heavy clump style trees in them. Normally drum pots are not glazed. “Flat-round” are for literati. Small round pots are ideal for accent plantings of grasses. Round - glazed is also suggested for flowering trees.

Literati – pots should be shallow, round or, hexagonal. The diameter should be equal to 1/3 of the height of the tree. Here colors tend to be earthy grays to browns.

Lotus shaped pots – Gustafson suggests crème colored glazed with arctic willow, birch, rosemary or heather. Lotus pots and hexagonal and rectangular pots should be planted with the tree centered as you would use a round pot. Generally, lotus shaped trees can be used with all the upright styles, but not clumps, groves or exposed root. Square and round pots were also not recommended with these three tree styles.

Placement of the tree in the pot:
Except for round or square pots the tree is never placed in the middle of the pot. The tree needs to have its mass balanced over the pots. Since bonsai with the exception of formal upright and broom styles are scalene triangles, they tend to have longer branches on one side or another. The tree is therefore, placed to the right or left of center.

Secondly the tree should lean slightly towards the viewer. This means most trees will need to be placed just a little behind the center axis.

Identify the “front” of the pot as well as the tree. If your pot has 4 feet, the feet should be right and left of center, even with a round pots. However if you have a round pot with only three feet, then one of the feet should be toward the front. With a cascade one of the feet should be where the cascade is lowest.

If you are using an irregular shaped pot, the lowest point on the rim should be towards the front. Irregular shaped pots or slabs are frequently used for groves, clumps of multi-trunked trees.

The following seven references may be consulted. Remember two things 1) The tree is the focus, the pot compliments the tree; and 2) You’ll eventually need to re-pot the tree, each time you do, you decide if the tree stays in the same pot or not.

1. Chan, Peter; copyright 2002 – Bonsai, Bonsai Pots, pages 104-105
2. Crespi, Luigi; copyright 1989 – Bonsai: the Complete Illustrated Guide to Growing and Caring for Miniature Plants and Trees, Containers, pages 46-47
3. Gustafson, Herb; copyright 1999 – Low Maintenance Bonsai, Pots, pages 9-18
4. Lang, Amy; copyright 1988 – The Living Art of Bonsai, Choosing the Pot, pages 258-263
5. Lewis, Colin; copyright 1993 – A Step by Step Guide to Growing and Displaying Bonsai, Pots, pages 38-39
6. Norman, Ken; copyright 1996 – Step by Step Create Your Own Bonsai 50 Step by Step Projects, Pots and Containers, pages 16-17
7. Zane, Thomas; copyright 1993 – Instructor’s Manual for Introduction to Bonsai – A Course Syllabus, pages 7.1 – 7.6