Phil Johnson is a horticulturalist, production manager and Best in Show winner, Chelsea Garden Show 2013. savewater!® interviewed Phil about vertical gardens and asked him to share his advice on a gardening technique becoming increasingly popular in residential and urban spaces.
Types of vertical gardens
The simplest vertical garden is strong mesh with a climbing plant on it. These are cheap and effective, but often don’t last very long without maintenance.
Wall gardens can be adapted to many different situations but most walls are not designed for gardens to hang off them. Consider additional support for your wall garden and if you are not sure ask for expert advice.
Wall gardens that support themselves with vertical loads directed to the ground are safer.
Some native plants that work well together in a vertical garden include:
- Baeckea virgate
- Correa alba
- Leucophyta brownii
- Olearia lirata
- Scaevola ‘Mauve Clusters’
5 plants that need constant moisture:
- Agapetes meiniana
- Asplenium australasicum
- Bromeliad guzmania
- Philodendron species
- Rhododendron lochiae
What type of soil best suits a vertical garden?
Use quality topsoil which includes elements of vermiculite, peat moss, sand and organic matter. Add a slow release fertiliser at the top of the wall garden where nutrients will flow downwards by watering.
Dripper systems with a flow rate of four litres/hour spaced five cm apart (normal drippers are spaced 30 cm apart) at the top of the garden which run for a short time (around five minutes) every four to six hours are best. You will likely have runoff at the bottom, so you will need to plan what to do with the excess water and reducing the likelihood of waterlogging your plants. You could do this by using a small pump. Alternatively you could bucket the water back to the vertical garden, a rain garden or another bed of stormwater.
What issues are associated with vertical gardens?
Damp and damage from water and plant roots (Ivy is famous for this) can be an issue. Use plastic sheeting on the wall behind wall gardens to prevent moisture absorption between the garden and the wall.
Simple vertical garden must-dos:
- Do water and fertilise regularly
- Do inspect the structure regularly
- Do try some fabulous native plants
- Do tip prune to keep plants compact
- Do replace dead plants
- Do replace soil for heavy feeders such as herbs and vegetables
- Do not set and forget
- Do enjoy!