Have You Heard of The 70/30 or 30/70 Landscape Rule?

The 70/30 and 30/70 Gardening Rules

Hello Treasure Valley gardeners.  During the past year or so, some of you have been asking what is the 70 30 rule and the 30 70 rule regarding landscape design , so here is information regarding those rules. Keep in mind that these are only guidelines in landscape design which many designers are following. This is just one of several design rules that landscape designers and landscape architects are applying in todays designs.

Gardening in the Boise and the Treasure Valley area comes with its own set of challenges: hot, dry summers, cold winters, alkaline soils, and unpredictable spring weather. That’s where the 70 30 and 30 70 gardening rules really shine. These simple ratios help local gardeners balance reliability, water-wise practices, and eye-catching beauty—without creating a high-maintenance headache.

Applying landscape principles

Understanding the 70 30 Rule (The Foundation Rule)

The 70 30 rule is best used for permanent landscapes and long-term plantings.

70% proven, climate-adapted plants and 30% annual plants

Why This Matters to Treasure Valley gardeners

Our climate rewards gardeners who choose tough, adaptable plants. Using the 70/30 rule ensures your garden looks good even during heat waves, water restrictions, or late spring frosts.

Treasure Valley-Friendly Plants for the 70% Rule

These plants are reliable performers in the Treasure Valley:

Perennials

• Coneflower (Echinacea)

• Black-eyed Susan (Rudbeckia)

• Daylily (Hemerocallis)

• Salvia

• Yarrow (Achillea)

Shrubs

• Spirea

• Potentilla

• Ninebark

• Russian Sage

• Boxwood (protected locations)

Grasses

• Blue fescue

• Feather reed grass

• Karl Foerster grass

These make up the backbone of a Treasure Valley-friendly landscape, these are hardy, drought-tolerant, and dependable plants.

The 30% Rule: Where You Get Creative

This is where gardeners can have fun:

• New plant varieties

• Bold colors or textures

• Plants that need extra water or attention

• Trending or specialty plants

• Back-yard living/relaxing areas

Examples for Treasure Valley gardens:

• Dahlias

• Specialty hydrangeas (with afternoon shade)

• Exotic annuals

• Unique foliage plants

If something struggles, it won’t derail the whole garden. Need help choosing the right plants? Visit with one of our retail staff members who can help you choose the right plants for your area of concern.

Water-Wise Gardening Using the 70 30 Rule

70% low-water plants and 30% moderate-water plants

With water conservation becoming more important in the Treasure Valley, this approach keeps irrigation costs down while still allowing for lush focal points near patios, entries, or seating areas.

The 30 70 Rule (The Impact Rule)

The 30 70 rule flips the ratio and is ideal for seasonal, high-visibility areas.

30% proven, climate-adapted plants and 70% color and seasonal interest

This rule is perfect for:

• Containers and hanging baskets

• Entryways

• Annual flower beds

• Front-yard focal areas

• Retail shops/subdivision entrances who want to draw attention to their location

Because these spaces are refreshed regularly, they can afford to be more colorful, bold, and experimental.

Best Plants for the 30 70 Rule in Boise

Annuals That Thrive Locally

• Petunias

• Geraniums

• Zinnias

• Calibrachoa

• Marigolds

• Verbena

Proven, climate-adapted plants (the 30%)

• Ornamental grasses

• Small shrubs

• Spikes (dracaena, cordyline)

• Compact evergreens

These provide height and form, while the annuals deliver nonstop color.

When to Use Each Rule in the Treasure Valley

Use the 70 30 rule for:

• Foundation plantings

• Perennial beds

• Water-wise landscapes

• Large yard designs

• Long-term planning

  
  

Use the 30 70 rule for:

• Containers and planters

• Seasonal color beds

• Entryways and curb appeal

• Event or holiday displays

• 
  

Why These Rules Work So Well in the Treasure Valley

Together, the 70 30 and 30 70 rules:

• Reduce plant loss from heat and cold

• Lower water usage

• Make gardens easier to maintain

• Create balanced, professional-looking landscapes

• Allow experimentation without risk

They’re especially useful for new gardeners, and busy homeowners.

A well designed landscape with the use of color

Smart Ratios for a Successful Treasure Valley Garden

These rules aren’t about strict math—they’re about gardening with intention. By building a strong, climate-adapted foundation and choosing where to add color and creativity, Treasure Valley gardeners can enjoy landscapes that look great all season long.

Use the 70 30 rule where reliability matters most, and the 30 70 rule where color and impact matter more and you’ll garden smarter, not harder.

Charlie Hartman – Idaho Certified Nurseryman