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Plant library  ·  Succulents & Cacti

Pencil Cactus

Euphorbia tirucalli

Pencil Cactus is an upright succulent shrub grown for its finely branched, green, pencil-like stems rather than a dense leafy canopy. Reaching about 15 feet tall and 8 feet wide, it creates a strong vertical element in warm-climate planting schemes. Give it a position where its open silhouette can be seen against a wall, fence, or simpler background planting.

  • Deer resistant
Sunlight Full Sun
Water Low
USDA zones 10–12
Spacing 6 ft
Mature size 15 ft tall, 8 ft wide

Placement and use

Use Pencil Cactus as a tall accent at the back of a dry, sun-exposed bed, or as a structural plant beside a broad wall or fence line. Its eventual height can shade lower planting nearby, so keep shorter sun-loving plants to its outer edges rather than directly on the shaded side. Leave a clear route for pruning and maintenance instead of setting it tight against paths, gates, or frequently used seating areas.

Spacing and mature footprint

Set plants 6 feet apart, center to center, for a linked vertical planting without crowding the stems at establishment. Each plant can broaden to roughly 8 feet, so a row will become more visually continuous as plants mature. For a specimen placement, reserve an 8-foot-wide footprint and allow additional clearance where people need to pass or work around it.

Three plants set 6 ft apart, center to center; shaded circles show the 8 ft mature spread.

Sun, water, and soil

Place this succulent in full sun and keep it in a low-water part of the plan. Well-drained soil is important, making raised, gravelly, or otherwise free-draining areas more suitable than sites that hold water after rain or irrigation. In very hot summer locations, some afternoon shade can moderate exposure while retaining a bright setting.[1]

Planning caveats

The milky sap calls for gloves during pruning, moving, or other hands-on work. Position the plant where routine contact is limited, and preserve enough open space to reach the base and outer stems without brushing through the plant. Its perennial presence makes this a long-term framework plant rather than a gap-filler for a temporary seasonal bed.

Growing facts

Botanical name
Euphorbia tirucalli
Type
Succulent
Category
Succulents & Cacti
Lifecycle
perennial
USDA hardiness zones
10–12
Sunlight
Full Sun
Water
Low
Plant spacing
6 ft
Mature size
15 ft tall, 8 ft wide
Pollinator friendly
No
Deer resistant
Yes
Native to North America
No

References

  1. Rubber Euphorbia - Euphorbia tirucalli — North Carolina Extension Gardener Plant Toolbox

Editorial content updated 2026-07-20.