Plant Spacing: when to go tighter vs more sparse

Plant labels will often give a range for their ideal spacing, for example 1-4 per linear metre, or 1-6 per m2. But how do you know what the correct spacing is for your individual project’s requirements? The wider you go, the easier weeds and erosion take over before the design establishes.

Plant too tight, and you might blow the budget without improving outcomes. There is an art and a science to planting density. Notice how the Cenchrus has filled in much faster than other plants, and there is a distinct opportunity for a stoloniferous groundcover to help plug gaps here.

Why This Matters

Plant spacing controls:

• Weed pressure
• Erosion risk
• Visual outcome
• Maintenance cost
• Project success in the first 6–24 months

The Core Decision

Ask this first: what does the planting need to do, and how quickly?

Goal	Spacing approach
Fast weed suppression	Tight
Slope stabilisation	Tight
Instant visual impact	Larger pot size, either tight or wide
Budget-driven install	Wider
Low priority and low erosion areas	Wider

 

When To Go Tight

Weed Suppression is Critical

• Public landscapes
• Commercial projects
• Areas with poor maintenance follow-up

Why

• Bare soil = weed establishment and erosion window

Slopes and Batters

• Roadsides
• Embankments
• Retaining edges

Why

• Water movement exposes gaps quickly
• Delayed coverage = increased erosion risk

Recommended approach

• Combine layers:
  • Densely planted stoloniferous groundcover tubes + strappy (true grasses are fast-growing compared with some other strappies)

High-visibility Areas

• Entries
• Streetscapes
• Civic spaces

Why

You don’t get 1+ years to “fill in”; you want instant or near-instant impact

Plant Types

• Stoloniferous plants and mass planting where individual shapes are not prioritised
• Tubestock, which cost less per individual plant

Why

Some plants naturally are suited to being densely planted, while others need a bit more space due to root competition and/or aesthetic considerations.

Planned Thinning

• Sometimes, it makes sense to over-plant with the plan to thin every second plant as they fill in

Why

Particularly useful for hedges and shrubbery where you want to go tubestock for better root establishment, then thin every second plant once branches start intermingling.

When Wider Spacing Can Work

Budget-driven Projects

Only where:

• Maintenance is realistic
• Expectations are lower

Fast-spreading Species in Low-risk Zones

Still requires:

• Weed control during establishment

Secondary or Background Planting

• Not focal areas
• Not slope-critical

Common Mistakes

• Applying one spacing rule across the whole site
• Treating all groundcovers as equal spreaders
• Ignoring establishment-phase weed and erosion pressure
• Prioritising installation budget over maintenance budget

Where to Get Plant Density Ranges

Use Ozbreed’s Desktop Specification Guide online:

Daniel’s Wrap

Plant spacing is tricky. Get it right, and the landscape establishes quickly, suppresses weeds, and performs as intended. Get it wrong, and you’ll blow the budget or weeds will take over. If the planting has a job to do, especially on slopes, in public spaces, or in high-visibility areas, spacing needs to support that from day one.

For project-ready densities and real-world guidance, use Ozbreed’s Desktop Specification Guide which is full of useful resources to make your life as a specifier easier.