GROWING STARTER TREES INTO GREAT BONSAI

A guide to developing your new young tree.

INTRODUCTION

This is designed to give you some tips to help in growing your new starter bonsai into a great bonsai tree.

The suggested methods I have put together here have been used for many years to develop bonsai without wasting many years by doing things in the wrong order and making some basic mistakes that will cost years of growing time.

They are intended to help you reach good results in a shorter period of time than it might otherwise take.

I have tried many techniques over the years and have found that some are better than others. These are only my suggestions, and you may want to do things differently according to your own experience and growing environment.

I will cover a few topics that will start at the early stages of growing seeds. From there we will go on to look at taking cuttings. More advanced propagating techniques such as air - layering will be covered in a different booklet.

The main thrust of this publication is to guide you through what to do with your newly acquired starter tree.

Sowing seeds.

This can be a daunting topic for many, especially if you have never tried it before.

I will just give some basic pointers that should help achieve better results. More detailed information can be found in my booklet about ‘Growing from seed’ available on the website.

• Prepare your seeds according to their needs for example - Clean them, soak them and stratify.

• When stratifying place them in small quantities in containers with 'barely damp' vermiculite or sand. If they are too wet they will rot and die. If you can squeeze water out of it then it is too wet.

• When they are ready for sowing, sow the seeds with the pointed end downwards.

  Sowing with the point down results in a relatively straight seedling without the awkward wiggly root at the base that will be difficult to deal with later on. If a pointed end is difficult to work out then plant with the part that was connected to the seed pod facing upward. This is often visible as a darker spot or slight dimple on one end.

• Sow them in a grid pattern at about 6-8mm deep, and 15-20mm apart. A good rule of thumb is to sow them as deep as they are long. (E.g. A seed that is 12mm long will want to be planted about 12mm deep.

  Sowing on this type of grid pattern helps to keep track of which seeds have germinated and how many.

• Sow them about 20-30mm apart. Don’t be tempted to overcrowd them as this will cause them to grow thin and weak and may also result in bad damping off and fungal infections..

• Sow in trays or pots filled with a 50/50 mix of suitable seed compost & sharp grit. You can also use other substrates such as fine akadama or plain grit or sharp sand.

• Water the trays gently so as not to wash seeds out.

• Place trays in a bright sheltered location outdoors or even better, in a greenhouse.

• Protect from frosts, hot sunshine, strong winds and wildlife such as mice. A mouse or bird will make short work of eating an entire tray of seeds overnight so protection is very important.

• When the seedlings have developed their second set of true leaves, it is time to transplant them into individual pots. Some species such as Acers will be better left alone for a year to develop strong roots before transplanting.

To Transplant Seedlings

• Fill each new container with a moist planting mix of your choice that is suitable for the variety of tree. I usually use an akadama based mix as this promotes fast healthy root growth.

• Loosen the soil around the seedlings (tweezers or a chopstick is handy for this); then carefully lift them out, one at a time. Handle seedlings carefully by their leaves to avoid damaging the tender stems.

• At this stage you can decide weather of not to cut any tap root off to encourage a more fibrous root that will make a better nebari in the long term. (It is best to use a razor blade to do this job.)

• Poke a hole in the new planting mix, place the seedling in the hole, and gently firm soil around it with your dibber or stick. Don't compress the soil too much.

• Gently water the transplant right away.

• Keep the containers out of direct sunlight for a few days to let the transplants recover from the move.

• You can begin to apply a plant tonic such as Rhizotonic to aid recovery.

• Before the seedlings go outside full time, harden them off so they can withstand bright sun and cooler temperatures. Put them outdoors for several hours each day in a wind-sheltered spot that receives filtered sunlight. A cold frame is useful for hardening off seedlings. Be sure to protect them from wildlife. Slugs, mice and birds will happily munch through such a tender salad.

• Over the next week or so, gradually increase exposure until the plants are in full sun all day.

• At this point you can start using weak organic fertilizer to help them grow.

Damping Off

If your seedlings suddenly collapse and die, one of the fungal diseases called “damping off” or “seed and seedling rot” may be to blame. In one type of damping off, the seedling’s stem collapses at or near the soil surface; in another type, the seedling rots before it emerges from the soil, or the seed decays before it even sprouts.

To prevent these problems, use clean sterilised or pasteurized potting mix and new or thoroughly washed and disinfected containers. A fungicide may be helpful but best practice is to;-

Take care not to overwater seedlings.

Be sure to provide good air circulation and ventilation, so tops of seedlings stay dry and standing moisture is kept to a minimum.

Growing on your young trees

 When the young plants are around 15-20cm tall and just becoming slightly woody, it will be time to apply the first wiring. If you are growing mame or shohin sized trees. If you are going to grow larger sizes this stage can be done at a later stage.

If you have bought your young trees, some of the plants you will receive may already have been wired at least once.

I advise resisting the temptation of 'slip potting' your new tree out of season because this will slow its development considerably. This is especially true of juniper species that take a long time to build up a dense pads of roots near the trunk.

Obviously as a young and tender plant they will be susceptible to bruising so you have to be careful when winding the wire on.

Once the wire is on you can gently put bends into the young plant.

Avoid bending it to and fro at the same spot as this will probably kill the young plant.

Be confident and place your bends carefully without making multiple adjustments.

At this stage I always make exaggerated bends because as the tree gets older the bends will tend to straighten out somewhat. Once you are happy with the shape its time to wait until the bend has set.

During this waiting period you can gradually increase the amount of fertiliser and get the plant growing strongly. Don’t prune anything at this stage.

The plant will need as many leaves as possible as these are the food production areas and the only way a plant converts the minerals you feed it into real plant food - sugars. So if you prune them the whole process will slow down dramatically and will cost you years of time instead of months.

Keep an eye on the young plants and allow them to grow freely. This will help to thicken the main trunk and invigorate the plant as a whole.

By the time they have doubled in height the wire will probably be starting to bite in.

Don’t worry, leave the wire in place so that it bites in a little but not too much and even less on deciduous plants.

Allowing the wire to bite in is especially important on coniferous species such as pines and junipers. Taking it off too soon will probably result in the tree straightening out almost all the way and the effort so far will be wasted.

With pines it is a good idea to leave the wire on until it bites in quite a lot. This causes swelling in the bark and helps to thicken the trunk and set the bends in place.

Don’t worry, any wire marks will grow out as the tree progresses and increases in girth.

If you want to have a taller tree it will be necessary to apply another wire along the full length of the trunk and put some extra bends into the parts that have not been previously wired and shaped. Avoid placing the wire into any previous wire marks but wire in the same direction as before.

 Once again, just allow the tree to grow freely without pruning anything in order to thicken the trunk and set the bends. Some species take longer than other to thicken up. Quince and some cotoneaster varieties for instance.

The next spring, if it is needed you can pot the tree into the next pot size up but don’t pot it into a pot that is too large.

Don’t prune any roots. Instead just tickle around the outside with a chopstick to encourage the new roots to grow outwards into the new soil. If using akadama based soil, it will probably all drop off which will give a good opportunity to arrange the roots into a spreading nebari.

 Repeat this process each year until the desired girth and height is reached. Along the way, keep an eye on the side branches and remove any that are growing from the inside of the bends. Side branches that are getting too thick can be reduced by half in order to slow them down but try keeping pruning to a minimum while the tree is trying to gain thickness.

The Future.

As the tree develops you can start to make the branches and wire them into place giving them bends to add character that will match the trunk line.

Don’t be tempted to plant the tree into a bonsai pot because that will slow everything down a lot and it will take you many years to make very little progress.

Keep the tree in a good sized training pot and feed regularly until the tree is pretty much finished.

Be on the look out for pests and diseases and treat them promptly with a suitable insecticide or fungicide.

Use fungicide proactively instead of waiting for a fungus to appear. Prevention is much better than cure.