How to Design a Vertical Garden: Placing Plants by How They Grow

Choosing healthy plants is only half the job. Where each plant sits on a vertical garden or green wall decides whether the wall looks full and balanced for years, or patchy within a few months. A fern that thrives in the middle of a wall can struggle in the top row, and a trailing plant in the wrong spot can smother everything below it.

This guide explains how plants grow on a vertical surface, how we position them on every wall we design, and the mistakes to avoid if you are planning your own vertical garden.

Why growth habit matters in a vertical garden

In a garden bed, every plant grows up from the same level. On a wall, plants are stacked on top of each other, so how each one grows changes what happens to its neighbours. Most vertical garden plants fall into one of three growth habits:

• Upright plants grow up and out in a fountain or clump, like Lomandra, Dianella, Bird’s Nest Fern and Philodendron Xanadu.
• Mounding plants form a soft, rounded cushion, like Boston Fern, Blue Star Fern, Heuchera, Calathea and Spider Plant.
• Trailing plants spill down and spread, like Bridal Veil, Pothos, Pig Face, Button Fern and Philodendron Lemon Lime.

Put a trailing plant at the top and it will hang over and shade the rows below. Put an upright plant at the bottom and it gets hidden behind everything above. Get the order right and every plant has room to show off.

The three tiers of a vertical garden

We build every vertical garden from the top row down, in three tiers:

• Upper rows: height. Upright growers give the wall a strong top edge and stop it looking flat.
• Middle rows: body. Mounding plants fill most of the wall and create the lush, layered look.
• Base rows: softness. Trailing and spreading plants cascade over the bottom pots so the wall finishes naturally instead of with a hard line.

The plants that suit each tier change with the aspect. On a sunny north or west facing wall, the top rows might be Lomandra and Dianella with Pig Face and Sedum at the base. On a shady south facing wall, it could be Bird’s Nest Fern and Philodendron Xanadu up top with Pothos and Button Fern trailing below. See our top plants for vertical gardens for the full list by aspect and tier.

How conditions change from the top of a wall to the bottom

Even within one vertical garden, conditions are rarely the same from top to bottom.

• Light. Eaves, pergolas and balconies above can shade the top rows, while the bottom rows may be shaded by fences, furniture or the plants above them.
• Wind and heat. Higher rows are often more exposed, so they can dry out faster on hot, windy days.
• Water. Water moves down through a wall, so lower rows tend to stay moister than upper rows.

Before choosing plants, look at the wall at different times of day and note where the light changes.

Irrigation programmed to suit each part of the wall

Different conditions mean different watering needs, so we don’t water the whole vertical garden the same way. We split the irrigation into zones and program each zone to suit its position. The more exposed areas, like sun-baked or windy sections, can be set to water more often or for longer, while sheltered areas get less so they don’t stay too wet.

This means every plant gets the water it needs for where it sits on the wall, rather than some drying out while others sit soggy. Programs can also be adjusted through the seasons, giving more water in summer and less in winter.

Design for the mature wall, not just day one

Plants keep growing after installation, and some grow much faster than others. A vigorous trailer next to a slow-growing fern will eventually take over. When planning a vertical garden, think about how big each plant will get and give the faster growers room, or plan to trim them during regular maintenance.

We grow our plants to maturity in our own nursery before they go on a wall, so it looks full from the day it is installed. Planting density also matters. In our system, you can choose 100% density (20 pots per square metre) for full coverage, 80% (16 pots) for a balanced look, or 60% (12 pots) for lighter coverage.

Using colour and texture

A wall of one plant can look flat. Mixing leaf shapes and tones makes it come alive. We design in three colour levels:

• Green texture: all-green plants in different tones and leaf shapes.
• Some colour: mostly green, with one coloured variety woven through.
• More colour: a balance of green and coloured foliage.

Coloured foliage, like Heuchera, Coleus, Syngonium and Philodendron Rojo Congo, holds its colour all year, so the wall looks good in every season.

Common vertical garden plant placement mistakes

• Putting trailing plants in the top rows, where they shade everything below.
• Planting upright plants at the base, where they get hidden.
• Using sun-loving plants on a shady wall, or shade plants on a north facing wall.
• Mixing thirsty plants and dry-loving plants on the same irrigation line.
• Dotting single plants randomly instead of repeating them so the eye can follow a pattern.
• Forgetting how big plants will get and letting fast growers swamp slow ones.

Get a vertical garden designed for your space

Every wall we design starts with the aspect, then the colour level, then the tiers, so the plants are in the right place from day one. Book a free design consultation and we will plan a wall that suits your space. Prefer to do it yourself? Our DIY kits come with plants chosen for your aspect. You can also read our guides to the best plants for green walls and vertical garden maintenance.