Why Did My Bonsai Die?

Here in the Pacific Northwest, it’s autumn and the leaves are starting to turn. As Halloween approaches, we turn our thoughts to candy, pumpkins, monsters, zombies, and death by frightening means.

Therefore it’s as good a time as any to look back at our dearly departed bonsai, and ask ourselves, “Why did they have to die? WHY?”

Here are the top five reasons your bonsai died an untimely death.

    You weakened your tree beyond its ability to recover.

      During different times of the year, your bonsai takes and expends energy to accomplish different tasks, such as creating new roots, foliage, or flowers. Energy taken includes photosynthesis, nutrients in the soil, anater.

      Most species of trees are potted/root-pruned/repotted in the spring, as new buds are beginning to swell and as the tree is waking from dormancy. Even before the buds swell, roots have awakened and are starting to develop new white tips, signaling that the tree is gearing up to explode with its first flush of growth. This is the time the tree is the most robust and able to handle the most abuse, especially deciduous trees.

      With deciduous trees, it’s good to maintain a similar proportion of root mass to foliage mass. If you take away a lot of roots, make sure there’s not too much fresh foliage because unhardened foliage requires energy from the roots, and when those roots have gone missing, the tree goes into shock and could die.

      Evergreen conifers, such as pines, junipers, spruce, and hemlock, however, cannot handle major removal of foliage and roots at the same time. Unlike deciduous trees, conifers need foliage to generate roots. You can only remove a lot of foliage on a conifer if you’re mostly leaving the roots alone.

      It’s also worth mentioning that you may be repotting too often. Better go too long than not long enough. Conifers in bonsai pots should be repotted every three to five years typically. Most deciduous trees can go at least two years between repottings, although there are exceptions for trees that grow roots very aggressively.

      Besides pruning, lots of wiring can damage the “plumbing” or flow of nutrients between roots and foliage. The tree will need to devote energy to healing micro-fractures. It does this by creating “reaction tissue” or forming scars, which in time will help hold the branch in position once the wire is removed. If you remove too much root mass, the tree will lack the strength to heal, and will weaken and possibly die.

      After doing any major work to a tree, it’s best to keep it shaded until it shows signs of new growth and recovery.

      So did you repot a tree after it put out a flush of spring growth? Did you style and repot a conifer at the same time? These are reasons it could have died. The best rule to follow is this: Only perform one major operation on a tree (styling or repotting) at one time. This requires delaying immediate gratification.

        You didn’t use pumice.

          If your tree suffered death by drowning, you didn’t use pumice. I write this article knowing full well that different growing conditions and climates require different soil formulas, and the area I live in is not unlike Japan, where bonsai got its name. Japanese growers use a very similar mix to what I’m about to describe.

          Do not use potting soil from the nursery. Do not use your backyard soil. Do not use Turface. That black thumb you have is rotting soil and roots in dirt.

          I realize that there are some who have found success with any of the aforementioned soils. Trust me: your trees will appreciate your using other means.

          Bonsai trees need a soil that holds a lot of oxygen and other gasses so that their feeder roots can grow in profusion and provide the energy needed to develop lush, compact growth and back-bud on older wood. The two best ingredients for bonsai soil are pumice and akadama. Generally akadama, a volcanic clay granule, is imported from Japan and can be hard to find. We like it because its molecular structure is perfect for holding moisture, nutrients, and air. Pumice holds plenty of water and anything will grow in it, especially if it’s screened to a uniform particle size like the middle screen size in a standard bonsai soil sifter.

          Soil must saturate and drain from top to bottom of the pot pretty easily. Pumice and akadama do this beautifully, and allow the necessary oxygen and gas flow for healthy roots. In our temperate climate, where we experience a decent amount of rainfall, we like the following:

          For deciduous trees:

            ·       50/50 pumice/akadama or
            ·       25/25/50 pumice/screened cinder/akadama of similar particle size.

            In hotter climates, try using more akadama or maybe screened fir bark to retain moisture. Find the person who grows the healthiest trees in your area and see what mix he or she uses. As long as it has pumice in it, you can emulate them.

            For conifers:

            We like 2/3 pumice or pumice/cinder to 1/3 akadama. 100% pumice alone will almost guarantee great root growth, so don’t sweat it if you can’t find akadama.

            So if your tree developed root rot (smelly soil and disintegrating roots are tell-tale signs), you didn’t use pumice. Let that be a lesson to you!

              You kept your tree indoors.

                Did the little bonsai you bought from the parking lot or mall vendor gradually loose color, and eventually turn brown? The grower probably didn’t emphasize that you really should grow your bonsai outside in a sunny location. Any bonsai made from a temperate species, such as juniper, pine, maple, elm, etc., is best kept outside. Ficus and other tropicals can live inside. Bring your outdoor bonsai in for a day or two every so often for your own enjoyment. But know that the dry air and lack of airflow will weaken and kill the tree.

                  You didn’t water the tree correctly.

                    Unless your tree is a wisteria in summer, do not water your tree by soaking the pot in a basin of water. Use a watering can or hose nozzle that allows a gentle shower of water to fall. If you are using good soil (see number 2, above), you should water when the surface of the soil and the area just below are dry. Use a fine showering nozzle and water until it pours out the drainage holes. There’s enough air in a properly draining soil to prevent death by drowning. Most species of tree used as bonsai appreciate as much sunlight as you can give them, and enough water to ensure they don’t dry out. So on hot summer days when temperatures exceed 80 degrees Fahrenheit, you may need to water twice or more. Temporarily putting the trees in shade is an option, but if they’re in the middle of a growth spurt the foliage will get leggy rather than compact. You don’t want that for bonsai.

                      You killed it with kindness.

                        In other words, you over-fertilized your tree. Trees in nature generally don’t get a lot of fertilizer. A tree that gets ample sun and the right amount of water will not die. You can weaken your tree when you fertilize it too soon after repotting (wait a month or so, until the tree has recovered and is showing signs of growth). Otherwise, too much fertilizer can burn new root tips.

                        There are plenty of other ways to kill a bonsai, which include hanging, torture, zombie bite, fire, and freezing to death. But if you do a post-mortem on your dead bonsai, the murder method will most likely be one or more of the ones listed here.

                        But don’t feel too bad: All bonsai growers have murdered a few trees through ignorance, neglect, or zeal. It’s sad but true. We also typically create many more trees than we kill through propagation of cuttings and seeds, so you can feel good about that.

                        If you think you might be a serial bonsai killer, and you can’t control your urges, it’s best to study with a bonsai professional or seasoned amateur whose work you respect. Learn from their success, and soon you’ll be a bonsai rescuer instead of a bonsai killer.