| General Description | Pinus thunbergii ‘Thunderhead’ is a fast-growing conifer, with more than 30 cm of growth each year in the proper conditions. It can be pruned with great success, making this specimen very easy to control. This specimen provides beautiful dark-green needles in thick rounded tufts.
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| ID Characteristic | A compact shrub form cultivar, it has dense, thick tufts of long dark green needles that are topped with a rounded long pointy bud. The cultivar has been compared to a cloud when fully grown, that has silvery new growth in the spring.
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| Shape | Depending on the maintenance given to the form of the specimen, its shape can vary. If left alone, the lateral branches will grow across whatever surface surrounds them. With continuous removal of lower lateral branches, it will grow upright and if pruned extensively it can be found in a dwarf form.
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| Landscape | Popular to use in any Japanese-Style Garden, this cultivar makes a great accent or specimen plant. It can be planted along oceanside similar to a bonsai and used for bank stabilization on a sandy hillside.
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| Propagation | This cultivar will need to be propagated with new growth cuttings. Dipping the cutting into a rooting hormone before planting is recommended, as it can take up to a year for the cutting to produce roots. Propagation can also be done by grafting onto a Pinus thunbergii rootstock.
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| Cultivation | Requiring sandy soil with a 5-7 pH, this cultivar can be very drought resistant once established. While young it will require a moist soil and may need frequent watering if in extensive heat. Wind burn can be a major concern, so protecting with a proper burlap wrapping in winter is recommended. |
| Pests | Overall, a very pest resistant pine, problems may occur if old dead needles are not removed from the dense foliage, causing restricted airflow. There have been reports of Pinus thunbergii ‘Thunderhead’ in western regions that do not have as dense of a growing pattern, leaving some areas with big gaps between clusters of needles.
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| Notable Specimens | Pinus thunbergii ‘Thunderhead’ can be found in the Gotelli Collection at the United States of America National Arboretum in Washington, DC.
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| Habitat | Horticultural origin.
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| Bark/Stem Description | Although mostly hidden by the dense foliage, the bark is very appealing and can be a great feature to this specimen. The younger branches are an orangey-yellow colour and become a dark grey almost black colour as they mature, growing up to 10 cm in diameter. A dark grey with deep grooves, the trunk has a scale like appearance and at maturity can be up to 15 cm in diameter.
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| Flower/Leaf Bud Description | Buds are of large valvate shape, appearing silvery-white in summer and white in winter. They are sticky and are the beginning of new growth, so there is not an exact size measurement, but winter buds will most likely be between 4 – 8 cm.
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| Leaf Description | Found in fascicles of 2 attached to the stem in tight whorls, these needles are approximately 1 cm wide and up to 13 cm long. Needles last between 3 – 5 years then turn light brown and fall in the spring. Needles are pointy and somewhat sharp to touch, and are dark green in colour.
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| Flower Description | This cultivar does not produce flowers.
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| Fruit Description | Mature specimens will produce an ovoid, conical, male brownish-black cone that is 5 – 8 cm long and up to 3 cm wide, sometimes in large quantities.
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| Colour Description | Dark green needles with silvery-white new spring growth and winter buds that are a unique beautiful white colour. As they age the needles will turn a light brown in colour.
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| Texture Description | A spiked appearance with smooth but sharp point needles and trunk bark that is rough to the touch with deep grooves. Branches add a smoother texture bark that is more scale-like.
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