The Arid House
In stark contrast to the rainforest, most arid habitats receive little rain and not very often. There is however plenty of light combined with soaring day temperatures and cold nights. In many arid regions it also snows and comparisons can be drawn between adaptations to this sort of habitat and alpine environments.
The plants in this house are very well adapted to conditions in the wild. Their survival depends upon it.
Many of the species we grow have arrived at similar solutions to overcome a lack of water. When it does rain these plants have the ability to take up water rapidly and store it in their succulent stems and leaves for later use.
Some plants of arid environments have evolved to use a very efficient form of photosynthesis. Plants using Crassulacean acid metabolism or CAM photosynthesis are able to keep stomata in the leaves and stems closed during the day to reduce water loss. At night these then open to collect carbon dioxide. This is stored as malate and used for photosynthesis during the day.
Rainfall is often the trigger for growth and flowering in arid plant communities. These seasonal weather patterns and mass flowerings can also coincide with the migration of pollinators such as birds. These visitors will feed from the flowers and inadvertently pollinate them at the same time.
Other species will flower at dusk when their pollinators appear. The Cereus uruguayanus is night flowering and provides a generous nectar reward to the visiting bats in return for pollination.
From the huddle of rotund Echinocereus grusonii to the armed leaves of the Agave tequilana and the towering tree aloes, what can be most striking about the plants grown in this house is the stunning diversity of form.