Succulents

Succulents are a group of plants able to store water in their leaves, stems, and roots.  This group includes between 8,000 and 10,000 species across several plant families, equal to 3%-5% of all plant species.  They are found on every continent except Antarctica.

Succulents are largely perennial species storing water for use in drought periods.  They have features that limit the amount of water loss from evaporation.  Most species have thick cuticles, the outer skin, and fewer stomata, the cells on the underside of leaves used for exchanging gases, including carbon dioxide and oxygen, with the outside environment.  Many plants exchange gases during non-daylight hours only.

By storing water, succulents are able to survive in habitats with limited water availability, including habitats that receive only dew or mist versus measurable rainfall.  Limited water availability may also refer to habitats where infrequent rainfall occurs with lengthy intervening dry periods. 

Additional water-saving features include round versus flat leaves and stems exposing less surface area to the air and thus reducing water loss through evaporation.  Plant surfaces may be waxy, hairy, or spiny creating micro-habitats to further reduce air movement across the surface.  Plants are able to seal and heal wounds quickly.  Roots are shallow allowing the plant to absorb minute amounts of moisture reaching the soil.

Plants retaining large amounts of water must have robust support to handle the extra weight.  In smaller plants, additional fiber strengthens stems and leaves.  In larger plants, such as trees and shrubs, stems contain thicker wood walls to maintain their upright stature.  This provides additional protection against wind damage.  In most species, if any part of the plant is broken off, fragments are capable of taking root and growing a new plant.

Since water temperature does not fluctuate as rapidly as air temperature, succulents are able to stay warmer due to the large amount of retained water.  Succulents are still vulnerable to damage at very low freezing temperatures, but only over a prolonged period of several hours.

Succulents are often found in homes and backyard gardens and are well-liked because of their low maintenance and unusual appearance.  Popular varieties that may come to mind include aloe vera, Christmas cactus, jade plant, sedum, and yucca.  Consider starting a small pot on your windowsill or planting some in your backyard.  Note: Be sure to pay close attention to the labels identifying which can be grown outdoors in your area.