Succulent Seeds | Mixed Succulent Plants
LATIN NAME: Succulent plants
COMMON NAME: Succulent Plants
Plant Profile
Succulent plants are not a family or an order. They are a group defined by a piece of anatomy: tissue that stores water, in leaves, stems or roots, in enough quantity to carry the plant through drought. The habit has evolved independently in more than thirty plant families, so the category is a horticultural convenience rather than a botanical one.
The trade groups them by where the water sits. Leaf succulents include Echeveria, Sempervivum, Aloe and Agave; stem succulents include most cacti and the euphorbias; root succulents include the caudiciforms, with swollen bases and thin stems. The distinction matters in cultivation, because each type rots in a different way and needs a different compost.
Almost all of them run CAM photosynthesis, fixing carbon dioxide at night and storing it as malate until daylight. That is the metabolic signature of the group, and it is why they can survive on a windowsill in full sun with almost no water. It is also why they grow slowly: the pathway is efficient in water and expensive in energy.
The families involved are worth knowing. Crassulaceae give sedum, sempervivum and echeveria; Aizoaceae give the mesembs and lithops; Cactaceae are all succulent; Euphorbiaceae contribute the stem forms; Apocynaceae contribute the stapeliads; Asparagaceae contribute sansevieria and its relatives. The rest are scattered.
Science & Biotechnology
Water storage is only half the adaptation. The other half is the surface: a thick cuticle, few stomata, sunken stomata, hairs, wax and a pale colour that reflects light. Some leaves are covered in bladder cells that hold water and salt, and some stems are ribbed so that they can swell without splitting. The engineering is consistent across families.
The shapes converge because the physics does not change. A sphere holds the most water for the least surface, so so many cacti are globular and why the columnar forms are ribbed. Spines and thorns are a second convergence, and they are not the same organ: cactus spines are modified leaves, while euphorbia spines are modified stipules.
Propagation is where the group repays its keep. A leaf of Echeveria or Graptopetalum will produce roots and a plantlet from a single cell layer at the cut end, and a stem cutting of any of them roots in a week. That is vegetative cloning on the cheapest possible terms, and it is why the trade can sell named forms at low prices. The rest of the Crassulaceae here runs to Hylotelephium spectabile, Sedum selskianum and Sedum rupestre.
Uses & Benefits
In the garden they are plants for the places where nothing else works: a hot wall, a gravel bed, a shallow bowl, a windowsill. They need a substrate that drains within seconds and a watering regime of soak and dry. The commonest cause of death is not drought but water at the root in cold weather, and the second is compost that holds it.
Indoors, light is the limiting factor and most failures are etiolation: the plant stretches toward a window, the growth becomes pale and weak, and the shape is lost for good. A south-facing windowsill in winter and a bright position in summer will keep most of them compact. Rotating the pot weekly helps, at the cost of a leaning plant.
A few are edible, and the group includes some real foods: the prickly pear, the dragon fruit, and the ice plant of South Africa. Most are not, and several are toxic, including the euphorbias with their milky sap and the kalanchoes with their cardiac glycosides. Eat nothing from a mixed collection unless you know exactly what it is.
Growing from Seed
Sow on the surface of a gritty, sterilised mix at twenty to twenty-five degrees, and do not cover the seed, which needs light. Germination takes one to four weeks and is uneven. Water from below and keep the pot humid but not wet. The seedlings are tiny and slow, and should stay in the seed pot a full season before potting on.
Pot into a mix of two parts grit, one part loam and one part leaf mould, or into a commercial cactus compost with extra grit. Water thoroughly and then let the pot dry completely before watering again. Feed once in spring with a dilute low-nitrogen fertiliser. Never water in the dormant season, which for most is winter.
Take leaf or stem cuttings in spring or summer, let the cut surface callous for a few days, and lay them on dry grit until roots appear. Then pot and water lightly. Division works for clumping forms such as sempervivum and aloe. Keep everything frost-free in winter unless you know the species is hardy, and check the label.
Our Take
The category is a convenience and it hides a lot of difference. A lithops and a prickly pear are both succulents and they want opposite treatment: one needs a summer drought and a winter wet, the other the reverse. Anyone who treats the group as a single thing will kill half of it. The label is a starting point, not an instruction.
Start with the easy ones: sempervivum outdoors, echeveria on a windowsill, sedum in a gravel bed. Learn the soak-and-dry rhythm and the difference between a plant that is thirsty and one that is rotting. After that the group opens up, and it ranks among the few that can be propagated for nothing from a leaf.
Related Reading
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