A red pine (akamatsu) bonsai trained in the informal upright style. Photo: Azukari
Stand a Japanese black pine and a Japanese red pine side by side and the eye reads them almost like two different people before it reads them as two different trees. One is broad-shouldered, its bark cracked and grey, its needles standing out stiff and dark. The other leans a little softer, its bark warm with a reddish cast, its needles finer and more relaxed. Japanese gardeners noticed this difference long before botanists gave the two species Latin names, and gave the pair a name of their own.
Akamatsu, the Japanese red pine, is bonsai's other great conifer — softer in the needle, warmer in the bark, and traditionally read as the gentle counterpart to the black pine's strength.
Two pines, one old pairing
Akamatsu (赤松, "red pine," Pinus densiflora) and kuromatsu (黒松, "black pine," Pinus thunbergii) have been planted, painted, and discussed together for so long in Japan that neither species is usually introduced without the other. Traditional garden vocabulary even gendered the pair: kuromatsu as otoko-matsu (男松, "male pine") and akamatsu as onna-matsu (女松, "female pine") — kuromatsu's needles thicker and its whole bearing more rugged, akamatsu's needles finer and its outline softer. The labels describe an aesthetic contrast rather than a biological one, and they have stayed in use mostly because the contrast itself is so easy to see once someone has pointed it out.
Where the softness comes from
Look closely and the difference sits in the needle. Both species carry their foliage in bundles of two, but kuromatsu's needles are stout, sharply pointed, and hold themselves out stiffly enough to prick a careless hand; akamatsu's are noticeably thinner and more pliant, gathered in soft tufts that give the whole crown a gentler outline even from a distance. Both trees are also what growers call two-flush pines — vigorous enough to push a second round of growth within a season — which is why akamatsu and kuromatsu, almost alone among pines grown as bonsai, can be decandled: the season's new candles are cut back in early summer to force a finer, denser second flush. The technique itself is identical on both species. What differs is only how soft the result looks once the new needles have hardened off.
The bark that gives the tree its name
Akamatsu earns its name from bark rather than foliage. On a young tree, the bark carries an orange-red cast and peels away in thin, papery scales; only at the base of an old trunk does it thicken into the grey, plated bark that kuromatsu wears from root to upper branch. It is that reddish upper bark, catching the light on an otherwise ordinary conifer, that is thought to have given the species its common name. Bonsai growers know this coloring can be slow to arrive inside a pot: a tree confined to a container for years may hold a duller bark for longer than one left to grow in open ground, so a strongly reddened trunk is usually read as a sign of real age rather than assumed of any akamatsu on sight.
Kuromatsu, the black pine — akamatsu's traditional pair, with thicker needles and bark that fissures dark grey from the base up. Photo: Azukari
The mountain pine, not the coastal one
The two pines part ways in the wild as clearly as they do in a display alcove. Kuromatsu tolerates salt spray and onshore wind well enough that it became Japan's default coastal pine, planted for centuries along dunes and shorelines as a windbreak. Akamatsu keeps mostly to drier ground further inland — thin-soiled ridges and low mountainsides where little else takes hold first. One quiet consequence of that habitat: in Japan and Korea, the prized matsutake (松茸, a highly valued autumn mushroom) grows in a mycorrhizal partnership chiefly with akamatsu's roots, fruiting in the same red-pine woodland the tree has favored for as long as anyone has been gathering mushrooms there. A black pine forest does not offer the same thing. It is one more way the two species, so often spoken of as a matched pair, have quietly kept to different rooms of the country.
A pair, not a rival
None of this makes akamatsu the lesser tree. In the vocabulary of Japanese gardens and bonsai display, otoko-matsu and onna-matsu were never meant to rank one pine above the other — they were meant to be read together, planted in pairs at shrine gates and garden entrances, the contrast itself being the point. A collection built entirely of kuromatsu can read as one register held too long; a single akamatsu placed nearby gives the eye somewhere softer to rest. The two pines share nearly every technique a grower uses on either one — the same decandling, the same seasonal rhythm of watering and repotting — and diverge mainly in what the finished tree is asked to say.
Closing
A bonsai collection that holds both pines is not hedging between two options. It is keeping the full range of what a Japanese pine can express — the black pine's weathered strength and the red pine's quieter warmth — in one place, the way Japanese gardens have kept them for centuries. Azukari works with artists in Japan who tend both species side by side, each one trained toward the register it does best, so that an owner joining a tree's seasonal care inherits not just a pine, but the half of the pair that particular tree was always meant to be.
For more on akamatsu's counterpart and its wider family, see "Kuromatsu: Japanese Black Pine," "Goyomatsu: Japanese White Pine," and "Types of Bonsai." For the coastal conditions that shaped kuromatsu specifically, see "What Coastal Pines Teach."
References
- The Gymnosperm Database — Pinus densiflora — native range, bark description ("red-brown, in large plates" on old trees, "flaky and papery" when young), and needle measurements.
- Seattle Japanese Garden — "Pine Trees, Part Two: Matsu, the Pines of Japan" — the male pine/female pine distinction between kuromatsu and akamatsu, and comparative needle and bark description.
- Bonsai Empire — Pines (Pinus) — needle comparison between the two species, the two-flush decandling technique they share, and the coastal-versus-inland habitat note.
- Wikipedia — Matsutake — the mushroom's mycorrhizal association with Pinus densiflora in Japan and Korea.
- Bonsai / The Shikoku Shimbun — "Akamatsu" — bonsai cultivation notes, including the slow reddening of bark on container-grown trees and sensitivity to over-fertilizing.