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Plants arboreous to shrubby; rhizomes leptomorph, tillering greatly in unfavourable sites. Culms to 2.5–20 m or more tall, 1-20 cm in diam., self-supporting, erect or nodding, solitary or unicaespitose; internodes profoundly flattened and doubly sulcate on one side above branches; nodes prominent, the supranodal ridge distinct. Branches 2(-3) per mid-culm node, erect to spreading, long, asymmetrical, basal nodes not compressed, 1 lateral only arising from basal node, all sheaths present, sheaths and prophylls more or less glabrous, deciduous, tough; buds at mid-culm indistinct with branches developing rapidly, open at front, no promontory, prophylls 2-keeled, 2 initials visible within. Culm sheaths promptly deciduous, tough; blade narrow, deciduous, usually reflexed. Leaf sheaths deciduous, blade small to medium-sized relative to stature, usually glossy and thickened, distinctly tessellate, usually proximally pilose on abaxial surface, branchlets with only 2-4 leaves. Synflorescence prominently bracteate, partially iterauctant, composed of 1–7-spikelet racemes gathered into fascicles or globose mass subtended by a tiny, membranous, 2-keeled prophyll, 0–1 gemmiferous bracts, 2–6 gradually enlarged scaly bracts and 2–7 spathiform bracts. Spikelets sessile with 2–7 florets, the terminal one sterile. Glumes 0–1(–3), Rachilla extending beyond uppermost floret, disarticulating just below fertile florets; lemmas varied in size and texture; palea 2-keeled, not exceeding the lemma, apex bifid. Lodicules 3, ciliate. Anthers 3, filaments free. Stigmas (1-)3. Fruit a caryopsis, elliptical to linear-lanceolate, dorsally grooved. Name from the Greek phyllon ‘leaf’ and stachys ‘spike’, alluding to the reduced leafy blades on the sheaths supporting the inflorescence.
Phyllostachys is a hardy genus of at least 50 species, native mainly to China from Hainan to the Yellow River, and from Yunnan to Taiwan, but introduced to surrounding countries, especially Japan.
Characterised by 2(-3) unequal branches at most nodes, with a complete lack of internodal compression, along with almost universal presence of buds at all branch nodes, Phyllostachys is the most distinct genus of hardy temperate bamboos. Most of the species and a very large number of cultivars with coloured culms have been introduced to western horticulture, especially to continental Europe and the US, where they are widely cultivated. Their taxonomy is as fraught with misidentifications and riddles as those of other bamboo genera. The attractive foliage with a limited number of leaves on well separated very upright culms, along with the 2 asymmetrical branches and prominent nodes give the classic Chinese bamboo appearance. Phyllostachys species are difficult to identify, as many of the main characters are visible only on young shoots and culms sheaths. Leaf sheaths are highly variable. Many different species have identical colour variations on the culms, causing confusion in identification to the correct species.
This is a difficult genus for me to cover from the UK, because few species are growing well here, and it is challenging to present identification details and photos appropriate for both the UK and continental Europe or the US. Moreover, while I was at Kew, the genus was the speciality of my boss. Other websites describing bamboos in this genus should be consulted, including:
Phyllostachys species grow best in a continental climate, with a hot summer and a cold winter to rest, and can produce the largest culms of all cultivated bamboos in areas with heavy frost. They do not thrive without plenty of sun, but they do not grow well in the tropics, as winters are too hot, or in areas having a pronounced monsoon climate, with a long dry season. They rarely grow to anything like their true potential in coastal northern Europe including the British Isles because of the cool summers, but several species are still cultivated here. Without optimum conditions, many species remain in a single small clump, producing short, thin, straggly culms with characteristics unusual for the species, and do not spread. However, a few species will grow large enough to become invasive, even in northern climates, and for those rhizome barriers are recommended to avoid unexpected incursions.
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 "2 or 3 branches of different sizes")
