Care and Maintenance Advice for Bonsai

Bonsai Care and Maintenance

Bonsai is an ancient horticultural practice of growing trees and shrubs into a well-manicured form of botanic art.  Years of careful training, pruning, root reduction, grafting and defoliation produce an ornate miniature version of a full sized specimen.  Bonsai are crafted primarily for contemplation by the viewer and an exercise of ingenuity exuding harmony and balance by the growerHere at Garden Plants, our bonsai inventory is selected from hardy specimens hand-picked by master gardeners and properly suited for the UK climate.  We have selected resilient native species such as Taxus Baccada and Japanese cultivars such as Ilex Crenata that will thrive in full or partial light conditions with an H6 or H7 hardiness rating for their resilience and take the mystery out of bonsai maintenance.

A bonsai tree is an investment that will bring a sense of balance and harmony to your garden and with a little yet effective maintenance will add decades of enlightenment to your garden.

Bonsai Planting Advice

The word Bonsai literally translates to “planted in a container” and these trees keep their miniature size by being trained into a container, but this training does not change the tree’s DNA.  A bonsai is trained by root restriction to limit size in a container, if you plant one in the ground it will start gaining size and revert to its natural state without proper care.  Therefore, it is recommended to keep your bonsai in a container and if you do ground plant it, make sure to take steps to keep its well-trained appearance.

Ground Planting

Ground Preparation

  1. The planting area should be approximately 3 times the diameter of the shipping container.
  2. Ideally the area of the planting area should be sprayed with a non-residual weed killer 4-6 weeks before planting. Remove all vegetation in the planting area before planting.
  3. Generally it is recommended to lay Planting Compost 5-8cm (3-5 in) over the immediate planting area and thoroughly mix it in with the soil with a gardening fork as deep as your spade will go after removing the top layer of vegetation before planting. If needed, amend the soil with Horticultural Gravel to improve drainage.

Day of Planting

  1. Dig a hole twice the diameter of the pot and 1¼ as deep and ensure that the hole has proper drainage at the bottom, preferably a layer of Horticultural Gravel. Typical bonsai planting mix is a 2-1-1 ratio of akadama, gravel and compost.  Akadama is granular clay that is specifically produced for bonsai trees.
  2. Carefully remove the plant ball from the pot and break up the bottom edges taking care to unfurl and tease out the roots from the base so that they will establish in the soil. Tap the side of the pot with your hand if the root ball is being stubborn and will not remove easily.
  3. Place the plant in the hole in a proper upright position with top part of the root ball slightly below ground level, approximately 5 cm (2in). Take a couple of steps back during positioning and look to make sure that the plant is positioned properly.
  4. After the plant is positioned properly, fill the area surrounding the hole halfway with a 50/50 mixture of native topsoil and Planting Compost. Fill the hole with water and allow the water to percolate down into the soil before filling in the remaining 50/50 mixture to ground level. This will allow the soil to bond with the roots and eliminate any air pockets.  Then fill in the remaining soil.
  5. Once backfilling is complete, tamp down the ground with your boot and make sure that you are just firming down the ground and not pushing down the soil.

Apply 5-8 cm (2-3 in) of mulch around the planting area, but do not allow the bark to touch the base keeping a ring around the trunk.  Mulch contact with the trunk could cause a fungal infection; hence it is preferable to form a “mulch donut” and not a “mulch volcano” around the trunk for best results. Water 2-3 times per week for the first two weeks after planting and then regularly for the first 3-6 months until the roots are established. After this initial period, it will only require watering during extended dry spells.

Container Planting 

Your new bonsai will come shipped in a container; younger trees need to be re-planted approximately every 2 years while older bonsai only need to be re-planted every 3-5 years.  Generally choose a container that is 20% larger than the previous one and ensure that there is proper drainage.  Bonsai generally need re-potting when the root system begins to choke itself off.  To determine if necessary, lift the tree from its pot gently and examine the root ball.  If the roots have begun to circle themselves, it is time for a new container.  This can lead to the tree starving itself as the roots will grow very thick and displace the soil.

  1. Timing is important and re-potting is generally done in early spring. The plant will experience less shock at this time of the year as it is not yet maintaining full foliage.  The subsequent spring growing season will also help real any damage from the procedure.
  2. Gently remove the tree from its container and remove as much as the old soil as possible. Delicately de-tangle the roots with your fingers if they have intertwined thickly while removing the soil.
  3. Prune back some of the longer roots to limit size and growth, but as a rule of thumb do not remove any more than 25% to the root length and total root mass.
  4. Place wire drainage mesh over the drain holes and cover with a bottom layer of Gravel for drainage at the bottom of the pot, but slightly cover with a base layer of mulch so the roots do not directly touch the gravel. Spread the roots out to the side when positioning the tree in the new container and gently backfill with the new potting mix while gently pressing down on the new soil.  Typical bonsai planting mix is a 2-1-1 ratio of akadama, gravel and compost.  Akadama is granular clay that is specifically produced for bonsai trees.
  5. Gently water the soil thoroughly after re-potting to eliminate air pockets and nourish the roots. Make sure to water the bonsai regularly afterwards, you can gently stick your finger into the potting mix to check for moisture.  If it feels dry, water it but like all plants do not waterlog.  You may choose to cover the soil with sand, decorative gravel or moss for presentation.

Proper potting and planting will create a harmonious balance between earth and tree that produces a vibrant, healthy specimen which will add enlightenment to your landscape.

Bonsai Trimming Advice

Maintenance pruning is mandatory for maintaining a bonsai’s shape and is performed throughout the growing season, generally from March to September. 

  1. Prune any new shoots or branches that outgrow the intended shape or canopy using twig shears or a normal cutter. Specially made bonsai tool sets (available under £8 ranging to £80 for a master set) aid significantly, make sure to always sharp and clean.  Don’t be shy; an occasional trim is important especially in the upper and top areas for even growth and dense foliage.
  2. Space out the major pruning so your bonsai has time to heal in between procedures. Pruning creates a wound, cut at a 45 degree angle to reduce injury and infection. This illustration shows which should be trimmed to maintain a proper form.

Proper pruning and trimming will maintain the form of your bonsai and keep the foliage healthy all year round.

Bonsai Watering Advice

Traditional bonsai are watered on a daily basis and always water gently at the base of the plant in the evening. Don’t spray the foliage as this can cause burning.  Check the soil regularly and water at least several times a week but do not waterlog.  Gently place your finger into the soil, if the soil feels dry add water.

Monitor your bonsai regularly, small amounts of effective maintenance will keep your plant health and vibrant.

Bonsai Feeding Advice

Feed your bonsai weekly during the growing season (March-April through September-October) for best results.  Dyna-Gro Bon-008 Bonsai-Pro Liquids plant food is one of our favourites; use ¼ teaspoon per gallon water for indoor plants and ½ teaspoon per gallon for outdoor.   If using bark mulch, replace every couple of months during growing season and don’t forget a fresh layer late autumn to keep the roots warm.

Use a tad bit of loving nourishment for your new bonsai and it will nourish your inner tranquillity for decades to come.