tree

Ombú

The Story

Plant Bio

Phytolacca dioica, commonly known as the ombú, is a massive evergreen tree native to the South American pampas, characterized by a rapid growth rate and a dense, rounded canopy. The species is dioecious, producing small, greenish-white flowers on drooping racemes up to eight inches long during spring and summer.

Despite its immense tree-like proportions, this species is botanically a giant herbaceous perennial with anomalous secondary growth that lacks true annual rings. The trunk base develops into a massive, swollen, water-storing pedestal with aggressive, visible surface roots that easily disrupt nearby pavement and structures.

Uses & Benefits:

Provides a dramatic, sculptural focal point with its massive, swollen trunk base and dense, glossy green canopy.

Functions as an effective shade provider in large, open landscapes and helps stabilize soil with its extensive root system.

Offers excellent nesting sites and dense canopy cover for local birds, while the fleshy berries provide food for fruit-eating species.

Essentials

At a Glance

Plant Type

Tree

Height

709"

Width

591"

Light

Full Sun, Partial Sun

Zones

9, 10

Water

Low

Humidity

Moderate

Lifespan

Long-lived

Native To

South America

Toxicity

Toxic if Ingested

Bloom period

Spring – Summer

In flower about 6 months of the year

Planting

How to Grow

Select a planting site in full sun with ample clearance for aggressive, wide-spreading surface roots.
Dig a hole twice the width of the root ball but no deeper, ensuring the swollen trunk base sits slightly above the surrounding soil level.
Backfill with native soil, pressing firmly to eliminate air pockets, and water thoroughly to settle the roots.
Irrigate moderately during the first growing season to establish the root system, then reduce watering significantly once the succulent trunk begins to swell.

Pro Tip

Avoid overwatering established specimens, as the succulent trunk tissues store ample water and are highly susceptible to fatal root rot in waterlogged soils.

Keep It Thriving

Care Guide

Do

Provide wide clearance from sidewalks, foundations, and underground pipes to accommodate the invasive surface roots.
Prune lightly during winter dormancy only when structural clearance is absolutely necessary.
Ensure the soil drains rapidly to prevent moisture accumulation around the trunk base.

Don't

Do not prune hard into old, leafless woody stems, as latent buds fail to push reliably from old wood.
Do not overwater or plant in low-lying areas where water pools.
Do not apply heavy fertilizer, as this species thrives in poor soils and excess nutrients cause weak, floppy growth.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Pest Check
Propagate
Prune
Winter Prep

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Specimen TreeShade TreeCoastal Gardens

Companion Plants

Quercus agrifolia Brachychiton acerifolius Agave americana

Multiply

Propagation Methods

Good to Know

Common Questions

Ombú questions

What zones can Ombú grow in?

Ombú is hardy in USDA Zones 9–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

When does Ombú bloom?

Ombú typically blooms in spring through summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Ombú need full sun?

Ombú does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Ombú drought tolerant?

Yes — once established (usually after the first full season), Ombú handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.