Dwarf mountain pine (mugo pine) is an evergreen coniferous plant from the mountainous regions of central and Southern Europe, so it prefers sun, but is also tolerant of partial shade. Grows only outdoors.

Pinus mugo has small, dark green needles that grow slowly. Being evergreen, the bonsai looks great all year round. Ideal for beginners because of its easy care. As with all pines, a change of seasons (temperature seasonal condition) is necessary.

Soil

Needs well-drained soil, coarse sand. Good results can be obtained from the use of Japanese soil mixtures (see here). Drainage at the bottom of the container is necessary: broken red bricks, expanded clay, lava.

Watering

Proper watering of a bonsai tree is the key to its health and beauty. The watering frequency depends on the time of year and the surrounding conditions, bonsai should be watered so that the soil is moist, but not wet.
During the growing season, from spring through summer, you may need to water your bonsai daily. If the weather is hot and dry, even twice a day. In cooler weather or if the bonsai is in a shady location, it may need to be watered every two or three days. You can determine if a tree requires watering with a moisture meter, a dry stick, a weight, or your finger. Overwatering is just as harmful as underwatering, but too little water is better than too much.

Fertilization

As with all bonsai trees, regular fertilization is necessary.
To avoid over fertilizing, you should use a fertilizer specifically designed for bonsai trees. It gives the plant all the nutrients it requires in smaller and more frequent amounts so that the tree can more easily absorb and utilize the nutrients (see here).

Repotting

Repotting should be done every two to three years for young pines and every three to five years for mature trees.
The best time to transplant is in late winter or early spring before new growth begins. This will give the tree a chance to adapt to the new container and get rid of stress before growth begins.
Carefully remove the tree from the old pot, straighten the compacted roots, cut off damaged, brown and underdeveloped roots. Place the tree in a new pot and pour the required amount of potting soil around it, tapping it lightly as you do so.
Then water well and place in a shady spot with diffused sunlight.
Do not fertilize the tree for at least 1 week after transplanting. The tree experiences transplant shock and cannot utilize the nutrients of fertilizer, which can eventually cause root.

Pruning

Primary pruning should be done at the same time as replanting. Further pruning can be made in the autumn. The new shoots (candles) should be plucked and shortened by two-thirds in spring, before the needles open. Pinch the candles in two stages: first pinch the strongest candles, and a week later the weaker candles. In the fall, reduce the number of buds on each branch to two to encourage branching and thin out the needles by removing any needles that are too long or growing downwards. Thin out more vigorously at the top of the tree and less as you move downward. This allows light to penetrate to the lower branches and slow the growth of the top.
Wire wrapping should be done in late fall or early winter and removed after 6–8 months, checking periodically to make sure the wire is not damaging the bark.

Diseases and pests

Root rot

Slow growth, needles turn pale and fall off. In case of severe infection, the plant may die.
Causes – excessive moisture in the soil, which provokes the development of fungal infections in the root system.
Provide good drainage in the pot, avoid excessive watering. If the disease is detected, transplanting with the removal of diseased roots and fungicide treatment is required.

Diaspididae

Appearance of small brown or gray growths on branches and needles, the plant begins to weaken.
Clean infected areas with soap solution or alcohol. In case of heavy infestation – use insecticides.

Aphids

Yellowing and twisting of needles, slow growth. Small green or black insects are visible on needles and young shoots.
Spraying with soap solution or garlic infusion. In case of severe infestation, insecticides are used.

Spider mite

Thin spider webs on branches and needles, needles lose color and turn brown.
Spraying with water or soap solution. In case of heavy infestation, acaricides can be used.

Strawberry root weevil

Slow growth, wilting of the plant. Otiorhynchus ovatus feed on the roots, which leads to their weakening.
Repotting and treating the soil with insecticides. It is also important to inspect the roots regularly.

General preventive measures

• Regular inspection: Inspect your bonsai for pests and diseases at least once a week.
• Watering moderately: over watering is a common cause of diseases, especially fungal.
• Good ventilation: keep bonsai in fresh air, avoiding stagnant air.
• Tool cleaning: Disinfect scissors and pruning tools after each use.
• Spraying and maintenance: regular spraying and wiping of the needles will help keep out dust and small pests.