Black Bamboo

Black Bamboo is hardy in zones 6-10, thriving in full to part sun. It prefers moist, fertile, well-draining soil but adapts to most soils as long as water does not sit around the roots. The single most important planting decision is containment, because this is a vigorous running bamboo.

Planting

1. Choose a site with full to part sun and room to spread, ideally where you can install a root barrier.
2. For running bamboo, install a high-density polyethylene rhizome barrier (about 24-30 in. deep) around the planting area, or plant in a large above-ground container or raised bed to keep it in bounds.
3. Dig the hole twice as wide as the root ball but no deeper, working organic matter into heavy or sandy soil.
4. Set the plant so the top of the root mass sits level with the surrounding grade; do not bury it deeper than it grew.
5. Backfill firmly and water in deeply to settle the soil and remove air pockets.
6. Mulch 2-3 in. over the root zone to hold moisture, keeping mulch off the canes.

For a privacy screen: space plants roughly 3-5 ft. apart in a row. Bamboo fills the gaps between plants quickly as the clump expands, so even spacing on the wider end of that range will knit into a solid screen within a couple of seasons.

Care & maintenance

• Containment first. Black Bamboo is a RUNNER that spreads aggressively by underground rhizomes. It must be contained with a deep root barrier, a sealed container, or by walking the perimeter each year and cutting or breaking off any rhizomes that escape. Skip this and it will travel into lawns and neighboring yards.
• Water. Keep consistently moist the first 1-2 years while it establishes. Bamboo is thirsty; water deeply in dry spells, including dry fall and winter periods, to keep foliage from browning.
• Feed. Apply a slow-release, high-nitrogen or lawn-type fertilizer in early spring to fuel fast cane growth.
• Light. Best color and density come in full to part sun.
• Thinning, not pruning. Rather than shearing, thin the clump: each year remove the oldest, fading, or weakest canes at ground level to keep the planting open, healthy, and showing off the black culms. You can also top canes to a desired height; a topped cane will not regrow taller but will leaf out below the cut.
• Mulch and tidy. Refresh mulch annually and clear dropped leaf litter as desired; the fine leaves break down into a useful natural mulch.
• Winter note. Hardy through zone 6, though canes and leaves may brown in a hard, exposed winter and flush again in spring. A sheltered spot improves winter appearance at the cold edge of its range.

Will it spread, and is it invasive?

Yes, Black Bamboo is a running bamboo. It sends out underground rhizomes that can travel several feet a year and pop up well away from the original clump, which is why it is considered aggressive if left unmanaged. It is not maintenance-free like a clumping bamboo. Plant it inside a deep (24-30 in.) rhizome barrier, in a sealed container, or in a spot where you will prune escaping rhizomes each year. Contained properly, it is a beautiful and well-behaved screen.

How far apart should I plant them for a privacy hedge?

Space plants about 3-5 ft. apart in a row. Because the clump expands outward, bamboo fills gaps faster than most screening plants, so you do not need to crowd them. Within a couple of growing seasons a row knits into a dense, tall screen.

How fast does it grow and how soon will it fill in?

It is fast. Established plants send up new canes each spring that can reach much of their height in a single season, and the screen typically fills in within two seasons. Like all bamboo, it spends the first year or two building a root system before the most dramatic top growth, so give it time to establish.

How tall and wide will it get?

Expect roughly 15-25 ft. tall and 5-10 ft. wide per planting, though the clump will keep expanding outward over time unless contained. You can hold it to a shorter height by topping the canes.

Why are the canes green and not black?

New culms emerge green and darken to their signature black over their first year or two as they mature, often turning fully ebony by the second season. A young plant will show a mix of green and black canes, which is normal and part of the appeal.

Why is my bamboo turning brown or dropping leaves?

The most common causes are underwatering and winter exposure. Bamboo is thirsty and browns quickly if it dries out, especially in hot or windy spells and through dry winters, so water deeply during dry periods. Some inner-leaf drop and a spring leaf exchange (old leaves shed as new ones flush) is normal. At the cold edge of its range, foliage and canes may brown in a hard winter and recover in spring.