The Opuntias are one of the largest genus of cacti. Most of them have flat, disc-shaped segments but there are small round jointed species and others with cylindrical segments. Only a few produce flowers unless they are in a very sunny position all the year round. They are slow growing, with many branches that are dotted with yellow, barbed bristles. They seldom develop flowers in the home.
Water moderately during the Spring and Summer. During the Winter give the plants only enough to prevent the potting mixture from becoming completely dry.
Give a high potash, tomato type fertilizer once a month throughout the active growth season.
Use a good porous potting mixture. Add 1 part of coarse sand or perlite to every 4 parts of soil-based or peat-based mixture. Most Opuntias need to be re-potted annually. Always examine its roots in Spring to determine wheter it needs re-potting.
In Spring or Summer remove a stem segment. Dust end of cutting and cut end of stem with hormone rooting powder containing fungicide. Allow it to dry for about 2-3 days. Insert cutting in a 2-3 inch pot of the recommended potting mixture for Opuntias.
Opuntias need as much direct sunlight as they can get all the year round.
Be careful not to splash water on the segmented kinds. Drops of water can spot the stems permanently. This is important with Opuntia Robusta.
Many of the Opuntias grown in pots sometimes need extra support. If the plant starts to sag over the side of the pot, insert a stake in the potting mixture and attach the plant to it.
Most plant cells look like little boxes full of green disks. The disks are called chloroplasts. Other organelles inside a plant cell include a nucleus (where the DNA is kept), a large central vacuole (where water and other materials are stored) and a complex internal skeleton or cytoskeleton made of various proteins.