Caring for Larch bonsai trees if you are taking your first steps in bonsai cultivation can be tricky and it is easy to be over-protective of this surprisingly hardy species. Here we provide guidance on how best to look after your trees.
Japanese Larch is more delicate than its European sister and the bigger collected specimens tend to be European. A deciduous, monoecious species, the branches grow in irregular whorls. The leaves are straight and develop from tight rosettes on short branch spurs that grow on older wood, in bunches on short, red side-shoots, and on the young growing shoots. They are spirally arranged. The colour is bright lime green at the start of the season, bright to dark green during the Summer and yellow in the autumn.
Varieties
There are many varieties of Larch from the common European Larch, larix decidua, to the exotic Himalayan Larch, larix griffithiana. The most popular Larch for bonsai cultivation is the Japanese Larch, larix kaempferi. It has a simple growth pattern, easily exploited by the bonsai grower. There is a species in North West America called larix lyallii which grows as a short dense shrub in its natural shape, and is accepted as an alpine form of Larch.
Collecting
In Northern Italy and indeed most of the Alpine region of Europe, the common Larch has great popularity as bonsai. Some of the trees I have either worked on or seen in collections are quite massive and attractive, but the only way to obtain a fine, large, ancient Larch is to collect them from the wild.
The problem is that many collected trees do not survive the first or second year. My
suggestion to you is that you wait until you have the experience of the species through growing nursery stock, and then for you to go collecting with an experienced bonsai grower and listen to their advice on proper and safe collecting techniques.
Remember to get permission; most people are OK about collecting as long as you leave no mess and close gates behind you. The Forestry Commission have even been known to encourage groups to clean out shrubby undergrowth or deer-chewed material. But the important thing is to ask!
After care of a collected tree
Daily spraying with a light mist will soon settle the tree and stop transpiration. The problem collectors find when lifting Larch is that the tree has a tendency to collapse in the first or second year.
One of the main reasons is that they over water the tree instead of simply misting it. Misting every day and watering only when the soil begins to dry, will gently let the tree get back together again. A 50-50 mix of peat and grit added to the existing soil is all you need to start with as long as this soil is free draining and does not retain water on the surface.
The reason I mention the use of existing soil is that the Larch, like the Pine, has beneficial mycelium fungus in the root area and this ‘symbiotic’ fungi helps balance the tree’s health and encourages more growth at root and upper levels. The fungus is a little like threads of cream coloured cotton wool thread. The only thing to watch for is a root aphid that has a blue-white coloured cotton wool thread. The colour is enough to differentiate the two, but if you also look really closely into the blue white fluff you will see tiny white oval aphids clustering about.
Remove as many as you can and then treat the whole root system with a systemic insecticide bath for about 30 minutes. If the tree remains healthy start feeding two months after the tree has settled down. Keep out of strong sunlight for the first three months and always out of wind. Cats and dogs, attracted by the ‘fresh dug’ smell, should be kept away.
Buying
Buying Larch from nurseries is usually expensive but if you find a commercial nursery you can pick up a few dozen seedlings for a small amount of cash. Buying a collected Larch is also possible from the larger bonsai nurseries or from a bonsai exhibition – watch the pages of the magazine for details of events. Some of the specialist nurseries occasionally have fine specimen bonsai imported from Japan (kaempferi) or China (potanii), but expect to pay into three figures for good specimens.
Most nurseries have quality Japanese Larch grown for a number of years; however, Larch grows quite quickly and if you start with a decent size tree you can have a nice bonsai in under five years.
Watering
If in good health water Larch every day in the growing season, but be careful that your bonsai does not get waterlogged.
One method I use is to reduce the outer 20% of soil around the perimeter of the pot and replace with either a mix of 50-50 akadama and peat or a 50-50 2mm grit and peat, leaving the original soil toward the middle of the tree to retain the mycelium fungus. This results in a looser free draining soil. In the winter when the weather is wet or cold, little water is required but in Spring the watering is increased to a daily routine. In warmer climates, such as the mountain regions of France, Italy or Spain, the natural trees get little water for a period of up to three months and this results in a tougher bark and shorter needle growth.
Thus I normally reduce watering to every second day in the middle of the summer for a period of three weeks so as to make the tree work for every drop it gets, consequently encouraging shorter needle growth and more corky bark.
Feeding
When young and after needles have opened, in the Spring feed full strength high nitrogen. During summer reduce feed but use a balanced fertiliser and then use a low or zero nitrogen fertiliser until the needles (leaves) begin to change colour to yellow in the Autumn. This is to achieve growth in the exact way you want.
All Larch buds grow in a twist around the twig. Cut back in January to the last buds of the last year’s growth but leave as the terminal bud on each twig a bud growing in the direction you want the new growth to grow in. I call this directional bud pruning, it is similar to the technique of pruning roses when you watch which way you cut stems back to the directional bud.
Pruning and maintenance
During winter months your bonsai will go through a period of dormancy, this is its natural defence against cold weather. This is a good time to undertake maintenance work and shape the tree if necessary.
Repotting
Best time is late January to early February. Pot colours should be grey, rust, brown or dark yellow ochre shades.
Caring for larch bonsai trees – seasonal calendar
This is a seasonal guide for caring for Larch bonsai trees in the Northern hemisphere.
February/March: Protect from severe weather conditions – keep sheltered from wind and extreme frost. Either cover with a cold frame or keep close up to the house. Repot in late January or early February.
April/May: When buds are coming out, start to feed every week at full strength to force the growth. This regime is reduced only when the tree is more or less finished and food reduction is used to maintain shape. This is the time for Aphids so watch carefully that an attack hasn’t happened when you turned your back. The aphid could destroy an otherwise healthy tree. This is a lovely time to view the little rosebuds of Larch leaves.
May/June: Continue to feed and start to pluck or break the long growth starting to form. Work from the top down.
Late June/July: Start to reduce food to every two weeks and feed a balanced food, e.g. an equal amount of NPK. Check the labels.
July/August: Change feed again to low nitrogen or zero nitrogen combination. Stop pruning until winter. This lets the tree get up strength before the dormant period.
September: When the tree changes its lime green colour to a brilliant yellow it makes up for any trouble your Larch has given you. It really is quite lovely.
October/November: Protect your tree from frosts, winds and over-wintering insects that may just want to spend their holidays in your Larch. Depending on how exposed your garden is will determine whether a cold frame is necessary. Larch bonsai, provided they’ve been properly acclimatised are hardy enough to handle a UK winter but be mindful of prolonged frost. Frozen soil around the roots will stop the tree from taking in moisture, however the top of the larch is still exposed to the wind and this could dry it out over time.
December/January: Structural ‘hard’ and maintenance pruning should take place in later winter.
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