For Bonsai, pines are especially popular and many people even regard them as the most typical Bonsai trees. Pine trees are evergreen, coniferous resinous trees with needles that appear in bundles of two to five.

The bark of older pine trees becomes scaly or flaky. Pines can grow in many different shapes in nature and can therefore be shaped in almost every known Bonsai style. In order to treat each pine species according to its nature, it is necessary to know if it produces only one or two flushes of growth during the growing season. Pine species with two flushes can be decandled in early summer to produce a second flush with shorter candles and smaller needles. Pine species with only one flush of growth must not be decandled because that would harm them, but the candles can be selected and shortened.

How to identify your pine species

The two well-known pine species which produce two flushes of growth per year are both from Japan and grow near the shores. Storms often break off their new candles in June and the trees are well adapted to producing a second flush afterwards. The Japanese Black Pine is a strong tree with long, dark green, hard needles in clusters of two. It grows more or less near by the sea. The Japanese Red Pine is more delicate and slender, has softer, thinner paired needles and looks similar to the Scots Pine. It grows a bit more uphill from the shore.

Pine species with only one flush of growth come from the mountains or are at least adapted to harsh conditions and short growth periods. The Japanese White Pine (also named five-needle pine) is a mountain plant with soft needles in clusters of five. It is more feminine in design and found at high mountain regions. It is often grafted on Black Pine root systems, for more stable growth. Dwarf cultivars of the White Pine include Zuisho, Kokonoe and Myojo. The Scots Pine grows all over Europe and even in Siberia. It has thin paired needles which can be slightly twisted and the bark in the upper part of the trunk is often reddish. The Ponderosa Pine is native to western North-America and the Rocky Mountains. It is a tall tree with very long needles in clusters of three. The bark of old Ponderosa Pines has yellow to orange or even pinkish plates with black crevices. The Mountain Pine is native to European mountains and often forms depressed shrubs on bedrock near the timberline. It has short, strong, dark green, paired needles and a dark brown bark. Its wood is very fibrous and resinous. Finally, the Pinus aristata (Bristlecone pine) mostly grows in Colorado and New Mexico.

Two flush pines: Japanese Black Pine (Pinus thunbergii) and Japanese Red Pine (Pinus densiflora).

One flush pines: Japanese white pine (Pinus parviflora), Scots Pine (Pinus sylvestris), Ponderosa Pine (Pinus ponderosa) and Mountain Pine (Pinus mugo, or Mugo pine).

If you need help identifying your tree, try our Bonsai tree identification guide.

Specific Bonsai care guidelines for two flush pines

General info: It is important to understand where our pine species live in nature and which characteristics they have, in order to know how to treat them correctly as a Bonsai tree. The Japanese Black and Red pines can lose their first flush of growth and some of their foliage due to storms which often occur in early or mid summer in Japan. Afterwards they can produce a second flush of growth quite quickly which matures until autumn. This incident can be copied by the Bonsai artist in order to achieve shorter needles on more compact shoots and extra ramification. But it is necessary that the growing season is long enough for the second flush to fully develop.

Position: Place the pine Bonsai outside in full sun. This helps the first and second flush of growth develop and adds to decreasing the needle size (needles grow longer if the tree doesn’t get enough sunlight). Pine trees are very hardy, but still need to be protected during the winter when they are planted in containers.

Watering: Be careful not to over-water, as Bonsai pines dislike permanent moisture. Good drainage is required. Protect the trees from excess rain while the second flush is developing because much water will make the needles grow longer than necessary.

Fertilizing: Fertilize weak trees all year round, as long as the temperatures do not drop too low. Fertilize healthy trees from early spring (March) to early summer until the candles are cut. Solid organic fertilizer should be applied at least three times at intervals of 4 weeks before decandling. Then stop fertilizing until the secondary candle growth has hardened. Fertilize again from early to late autumn.

Pruning: Remove the candles in early to mid summer on healthy trees, leaving only a small stub of about 5 mm with a few pairs of needles. Cut off the tip of dormant buds to activate their growth. In autumn, after the second growth has matured, remove surplus shoots. Where more than two are growing from the same point, select two which are growing lateral and in the desired direction, form a v-shape and are of the same strength. Remove the others. In strong parts of the tree pluck excess old needles to balance the growth of the tree.

Wiring: Wire the pines from early autumn to early spring, or just after candle pruning in early to mid summer.

Repotting: Repotting is best done in spring just after the buds begin to swell.

Propagation: Pines can be propagated from seed or by grafting. Some can be airlayered.

Pests and diseases: Pines can be affected by aphids, spider mites, scale or caterpillars. Sometimes they are also attacked by fungal diseases and root rot. Specific pesticides must be used in that case and it is recommended to get help from an expert in this situation, because pines can die quickly from the moment the first sign of disease gets visible. But if pines are placed in a sunny position and are cared for properly they tend to be very healthy.

For more detailed information on these techniques, try our Bonsai tree care section.

Specific Bonsai care guidelines for one flush pines

General info: Unlike the pine species mentioned above, most other pines will only produce one flush of growth each year. It could be fatal to remove all their candles, so they must be treated differently. Included in this category are the White Pine, Scots Pine, Ponderosa Pine and Mountain Pine.

Position: Place the pine outside in full sun. This supports healthy growth and helps decrease the needle size (needles grow longer if the tree doesn’t get enough sunlight). Pine trees are very hardy, but still should be protected during the winter when they are planted in containers.

Watering: Be careful not to over-water, as Bonsai pines dislike permanent moisture. Good drainage is required. Protect the trees from excess rain while the shoots are developing because much water will make the needles grow longer than necessary.

Fertilizing: Fertilize weak trees year round as long as the temperatures do not drop too low. Healthy trees are fertilized from early spring to late autumn.

Pruning: Elongated candles should be shortened to an appropriate and even length from late spring to early summer. If there are more than two candles in the same place you can already cut off all but two. In autumn you can remove surplus shoots if you have not done so in spring. Where more than two are growing from the same point, select two which are growing lateral and in the desired direction, form a v-shape and are of the same strength. Remove the others. In strong parts of the tree pluck excess old needles to balance the growth of the tree.

Wiring: Wire the pines from early autumn to early spring, or just after candles are shortened in early to mid summer.

Repotting: It is best to repot in spring just after buds begin to move. You can also repot pines in late summer or early autumn when temperatures are not so high anymore but there is still enough time for the tree to regrow fine roots before winter.

Propagation: Pines can be propagated from seed or grafting. Some can be air-layered and some can even be grown from cuttings (Zuisho White Pine for example).

Pests and diseases: Pinus Bonsai can be affected by aphids, spider mites, scale or caterpillars. Sometimes they are also attacked by fungal diseases and root rot. Specific pesticides must be used in that case and it is recommended to get help from an expert in that situation, because pines can die quickly from the moment the first sign of disease gets visible. But if pines are placed in a sunny position and are cared for properly they tend to be very healthy.

For more detailed information on these techniques, try our Bonsai tree care section.

Example of a Pine Bonsai tree