Plants generally have an amazing ability to survive and grow in some of the most inhospitable of places. It’s sometimes hard to understand how they manage it, especially as we’re used to seeing plants growing in deep soil. For example, the edge of cliffs, on roofs as well as in between paving slabs and on top of walls. These plants can transform your wall cracks and crevices into living features.
Understanding a plant’s basic needs can help explain these mysteries. Most plants need air, water, light, and food to survive and grow. Also, they need somewhere for their roots to be anchored to keep the plant stable.
Soil usually gives plants three out of those four things and, where space is unlimited, the plants can grow extensive root systems, so they grow into large specimens.
Plants can also be extremely adaptable and limit their growth to their environment. For example, if a seed falls into a crack in a paving slab, it will often be able to germinate, develop roots and leaves and then start to grow.
But because its roots are limited it will always be relatively short compared to the size it would have grown to if given unlimited space. This is the same principle as bonsai plants, just nature’s way of doing it naturally!