In the age of small apartments, the next generation is looking up when it comes to gardening. How do we go about designing vertical rock gardens? What do we need to consider and which types of plants would grow on a rock face?
We will be touching on all of the frequently asked questions while giving you some ideas for your next project.
Only as good as its foundation
Building a rock garden can be anything from easy to intricate. It may just mean placing a few large keystones on an elevated mount or artistic stonecutting arranged into a wall.
Whatever you decide to choose, make sure that the foundations are sturdy. What do I mean by this? Once you start adding plants to a rock garden, the structure should support both the weight of the plants and soil (in terms of a wall) and be able to keep them alive (too much clay or sand, or not enough soil will pose problems).
Tip | Large rocks are statement pieces, but rarely have crevices to plant into. Rather use it as a structural piece in the garden.
Tip | Constructing a rock wall can be expensive, but an alternative is to use a Gabion basket (wire box filled with stones).
Building on an incline may be tricky once a severe rainstorm comes through, so opt for terraces if possible. Equally important is to note that if you want to build a rock wall on a balcony, you would be better off using lightweight or faux rock (this is to ensure the balcony can handle the weight).
Water on a vertical face
Smaller pockets of soil will dry out quicker than larger pots, which means you will need to water the plants on a vertical wall far more often than you are used to. You can modify the soil to retain more moisture by adding water-retentive additives.
For more on soil additives see:
A vertical wall will heat up during the day, irrespective of what material you use (faux or real rock). When selecting your rocks, you will need to take into account how warm the structure will get during the day. Succulents that can withstand full sun will still burn from rocks that hold onto heat.
It is in the roots
Picking plants for your rock wall can be exhilarating to the extent that you might opt for plants that cannot really do what you want them to. You might be considering a tropical wall or the more waterwise succulent wall, but what it boils down to are roots.
You want scrambling plants that will stick to the wall without help, or trailing plants that do well in small openings (aka small root system).
Great examples are the following:
- Ferns (small root system, constant watering)
- Bulbophyllum (grow on moss-covered rocks, constant watering)
- Monstera (for dry-wet cycles)
- Philodendron (for dry-wet cycles)
- Pothos (for dry-wet cycles)
- Satin Pothos (for dry-wet cycles)
Last but not least, once you have your plants situated, they will likely start establishing roots. During this process, you will need to make sure to provide enough moisture. The plants may drop leaves, start to wrinkle etc. The 1st few weeks are critical.
Keep an eye on the following:
- How fast the soil dries (too fast and the plants cannot take it up)
- Plants that do not bounce back (stay wrinkled for weeks)
- Bleaching or sunburn on your plants
This period will not necessarily see active growth in terms of new leaves. So start off with plain old water and gradually migrate to fertilisation in diluted amounts once you see new leaves.